A specific mannose-binding member of the collectin family of lectins. It binds to carbohydrate groups on invading pathogens and plays a key role in the MANNOSE-BINDING LECTIN COMPLEMENT PATHWAY.
A class of C-type lectins that target the carbohydrate structures found on invading pathogens. Binding of collectins to microorganisms results in their agglutination and enhanced clearance. Collectins form trimers that may assemble into larger oligomers. Each collectin polypeptide chain consists of four regions: a relatively short N-terminal region, a collagen-like region, an alpha-helical coiled-coil region, and carbohydrate-binding region.
Complement activation triggered by the interaction of microbial POLYSACCHARIDES with serum MANNOSE-BINDING LECTIN resulting in the activation of MANNOSE-BINDING PROTEIN-ASSOCIATED SERINE PROTEASES. As in the classical pathway, MASPs cleave COMPLEMENT C4 and COMPLEMENT C2 to form C3 CONVERTASE (C4B2A) and the subsequent C5 CONVERTASE (C4B2A3B) leading to cleavage of COMPLEMENT C5 and assembly of COMPLEMENT MEMBRANE ATTACK COMPLEX.
A hexose or fermentable monosaccharide and isomer of glucose from manna, the ash Fraxinus ornus and related plants. (From Grant & Hackh's Chemical Dictionary, 5th ed & Random House Unabridged Dictionary, 2d ed)
Complement activation initiated by the interaction of microbial ANTIGENS with COMPLEMENT C3B. When COMPLEMENT FACTOR B binds to the membrane-bound C3b, COMPLEMENT FACTOR D cleaves it to form alternative C3 CONVERTASE (C3BBB) which, stabilized by COMPLEMENT FACTOR P, is able to cleave multiple COMPLEMENT C3 to form alternative C5 CONVERTASE (C3BBB3B) leading to cleavage of COMPLEMENT C5 and the assembly of COMPLEMENT MEMBRANE ATTACK COMPLEX.
Complement activation initiated by the binding of COMPLEMENT C1 to ANTIGEN-ANTIBODY COMPLEXES at the COMPLEMENT C1Q subunit. This leads to the sequential activation of COMPLEMENT C1R and COMPLEMENT C1S subunits. Activated C1s cleaves COMPLEMENT C4 and COMPLEMENT C2 forming the membrane-bound classical C3 CONVERTASE (C4B2A) and the subsequent C5 CONVERTASE (C4B2A3B) leading to cleavage of COMPLEMENT C5 and the assembly of COMPLEMENT MEMBRANE ATTACK COMPLEX.
A subclass of lectins that are specific for CARBOHYDRATES that contain MANNOSE.
Proteins that share the common characteristic of binding to carbohydrates. Some ANTIBODIES and carbohydrate-metabolizing proteins (ENZYMES) also bind to carbohydrates, however they are not considered lectins. PLANT LECTINS are carbohydrate-binding proteins that have been primarily identified by their hemagglutinating activity (HEMAGGLUTININS). However, a variety of lectins occur in animal species where they serve diverse array of functions through specific carbohydrate recognition.
The sequential activation of serum COMPLEMENT PROTEINS to create the COMPLEMENT MEMBRANE ATTACK COMPLEX. Factors initiating complement activation include ANTIGEN-ANTIBODY COMPLEXES, microbial ANTIGENS, or cell surface POLYSACCHARIDES.
The genetic constitution of the individual, comprising the ALLELES present at each GENETIC LOCUS.
A glycoprotein that is central in both the classical and the alternative pathway of COMPLEMENT ACTIVATION. C3 can be cleaved into COMPLEMENT C3A and COMPLEMENT C3B, spontaneously at low level or by C3 CONVERTASE at high level. The smaller fragment C3a is an ANAPHYLATOXIN and mediator of local inflammatory process. The larger fragment C3b binds with C3 convertase to form C5 convertase.
A subcomponent of complement C1, composed of six copies of three polypeptide chains (A, B, and C), each encoded by a separate gene (C1QA; C1QB; C1QC). This complex is arranged in nine subunits (six disulfide-linked dimers of A and B, and three disulfide-linked homodimers of C). C1q has binding sites for antibodies (the heavy chain of IMMUNOGLOBULIN G or IMMUNOGLOBULIN M). The interaction of C1q and immunoglobulin activates the two proenzymes COMPLEMENT C1R and COMPLEMENT C1S, thus initiating the cascade of COMPLEMENT ACTIVATION via the CLASSICAL COMPLEMENT PATHWAY.
The regular and simultaneous occurrence in a single interbreeding population of two or more discontinuous genotypes. The concept includes differences in genotypes ranging in size from a single nucleotide site (POLYMORPHISM, SINGLE NUCLEOTIDE) to large nucleotide sequences visible at a chromosomal level.
A class of animal lectins that bind specifically to beta-galactoside in a calcium-independent manner. Members of this class are distiguished from other lectins by the presence of a conserved carbohydrate recognition domain. The majority of proteins in this class bind to sugar molecules in a sulfhydryl-dependent manner and are often referred to as S-type lectins, however this property is not required for membership in this class.
Serum glycoproteins participating in the host defense mechanism of COMPLEMENT ACTIVATION that creates the COMPLEMENT MEMBRANE ATTACK COMPLEX. Included are glycoproteins in the various pathways of complement activation (CLASSICAL COMPLEMENT PATHWAY; ALTERNATIVE COMPLEMENT PATHWAY; and LECTIN COMPLEMENT PATHWAY).
A glycoprotein that is important in the activation of CLASSICAL COMPLEMENT PATHWAY. C4 is cleaved by the activated COMPLEMENT C1S into COMPLEMENT C4A and COMPLEMENT C4B.
A latent susceptibility to disease at the genetic level, which may be activated under certain conditions.
Serum serine proteases which participate in COMPLEMENT ACTIVATION. They are activated when complexed with the MANNOSE-BINDING LECTIN, therefore also known as Mannose-binding protein-Associated Serine Proteases (MASPs). They cleave COMPLEMENT C4 and COMPLEMENT C2 to form C4b2a, the CLASSICAL PATHWAY C3 CONVERTASE.
A glycine-rich, heat-labile serum glycoprotein that contains a component of the C3 CONVERTASE ALTERNATE PATHWAY (C3bBb). Bb, a serine protease, is generated when factor B is cleaved by COMPLEMENT FACTOR D into Ba and Bb.
Protein or glycoprotein substances of plant origin that bind to sugar moieties in cell walls or membranes. Some carbohydrate-metabolizing proteins (ENZYMES) from PLANTS also bind to carbohydrates, however they are not considered lectins. Many plant lectins change the physiology of the membrane of BLOOD CELLS to cause agglutination, mitosis, or other biochemical changes. They may play a role in plant defense mechanisms.
A component of the CLASSICAL COMPLEMENT PATHWAY. C2 is cleaved by activated COMPLEMENT C1S into COMPLEMENT C2B and COMPLEMENT C2A. C2a, the COOH-terminal fragment containing a SERINE PROTEASE, combines with COMPLEMENT C4B to form C4b2a (CLASSICAL PATHWAY C3 CONVERTASE) and subsequent C4b2a3b (CLASSICAL PATHWAY C5 CONVERTASE).
Transport proteins that carry specific substances in the blood or across cell membranes.
The larger fragment generated from the cleavage of COMPLEMENT C3 by C3 CONVERTASE. It is a constituent of the ALTERNATIVE PATHWAY C3 CONVERTASE (C3bBb), and COMPLEMENT C5 CONVERTASES in both the classical (C4b2a3b) and the alternative (C3bBb3b) pathway. C3b participates in IMMUNE ADHERENCE REACTION and enhances PHAGOCYTOSIS. It can be inactivated (iC3b) or cleaved by various proteases to yield fragments such as COMPLEMENT C3C; COMPLEMENT C3D; C3e; C3f; and C3g.
The first complement component to act in the activation of CLASSICAL COMPLEMENT PATHWAY. It is a calcium-dependent trimolecular complex made up of three subcomponents: COMPLEMENT C1Q; COMPLEMENT C1R; and COMPLEMENT C1S at 1:2:2 ratios. When the intact C1 binds to at least two antibodies (involving C1q), C1r and C1s are sequentially activated, leading to subsequent steps in the cascade of COMPLEMENT ACTIVATION.
A multifunctional galactin initially discovered as a macrophage antigen that binds to IMMUNOGLOBULIN E, and as 29-35-kDa lectin that binds LAMININ. It is involved in a variety of biological events including interactions with galactose-containing glycoconjugates, cell proliferation, CELL DIFFERENTIATION, and APOPTOSIS.
C5 plays a central role in both the classical and the alternative pathway of COMPLEMENT ACTIVATION. C5 is cleaved by C5 CONVERTASE into COMPLEMENT C5A and COMPLEMENT C5B. The smaller fragment C5a is an ANAPHYLATOXIN and mediator of inflammatory process. The major fragment C5b binds to the membrane initiating the spontaneous assembly of the late complement components, C5-C9, into the MEMBRANE ATTACK COMPLEX.
Serum proteins that negatively regulate the cascade process of COMPLEMENT ACTIVATION. Uncontrolled complement activation and resulting cell lysis is potentially dangerous for the host. The complement system is tightly regulated by inactivators that accelerate the decay of intermediates and certain cell surface receptors.
A serum protein which is important in the ALTERNATIVE COMPLEMENT ACTIVATION PATHWAY. This enzyme cleaves the COMPLEMENT C3B-bound COMPLEMENT FACTOR B to form C3bBb which is ALTERNATIVE PATHWAY C3 CONVERTASE.
Serine proteases that cleave COMPLEMENT C3 into COMPLEMENT C3A and COMPLEMENT C3B, or cleave COMPLEMENT C5 into COMPLEMENT C5A and COMPLEMENT C5B. These include the different forms of C3/C5 convertases in the classical and the alternative pathways of COMPLEMENT ACTIVATION. Both cleavages take place at the C-terminal of an ARGININE residue.
A 53-kDa protein that is a positive regulator of the alternate pathway of complement activation (COMPLEMENT ACTIVATION PATHWAY, ALTERNATIVE). It stabilizes the ALTERNATIVE PATHWAY C3 CONVERTASE (C3bBb) and protects it from rapid inactivation, thus facilitating the cascade of COMPLEMENT ACTIVATION and the formation of MEMBRANE ATTACK COMPLEX. Individuals with mutation in the PFC gene exhibit properdin deficiency and have a high susceptibility to infections.
Molecules on the surface of some B-lymphocytes and macrophages, that recognize and combine with the C3b, C3d, C1q, and C4b components of complement.
An important soluble regulator of the alternative pathway of complement activation (COMPLEMENT ACTIVATION PATHWAY, ALTERNATIVE). It is a 139-kDa glycoprotein expressed by the liver and secreted into the blood. It binds to COMPLEMENT C3B and makes iC3b (inactivated complement 3b) susceptible to cleavage by COMPLEMENT FACTOR I. Complement factor H also inhibits the association of C3b with COMPLEMENT FACTOR B to form the C3bB proenzyme, and promotes the dissociation of Bb from the C3bBb complex (COMPLEMENT C3 CONVERTASE, ALTERNATIVE PATHWAY).
A product of COMPLEMENT ACTIVATION cascade, regardless of the pathways, that forms transmembrane channels causing disruption of the target CELL MEMBRANE and cell lysis. It is formed by the sequential assembly of terminal complement components (COMPLEMENT C5B; COMPLEMENT C6; COMPLEMENT C7; COMPLEMENT C8; and COMPLEMENT C9) into the target membrane. The resultant C5b-8-poly-C9 is the "membrane attack complex" or MAC.
The large fragment formed when COMPLEMENT C4 is cleaved by COMPLEMENT C1S. The membrane-bound C4b binds COMPLEMENT C2A, a SERINE PROTEASE, to form C4b2a (CLASSICAL PATHWAY C3 CONVERTASE) and subsequent C4b2a3b (CLASSICAL PATHWAY C5 CONVERTASE).
A 105-kDa serum glycoprotein with significant homology to the other late complement components, C7-C9. It is a polypeptide chain cross-linked by 32 disulfide bonds. C6 is the next complement component to bind to the membrane-bound COMPLEMENT C5B in the assembly of MEMBRANE ATTACK COMPLEX. It is encoded by gene C6.
Endogenous proteins that inhibit or inactivate COMPLEMENT C3B. They include COMPLEMENT FACTOR H and COMPLEMENT FACTOR I (C3b/C4b inactivator). They cleave or promote the cleavage of C3b into inactive fragments, and thus are important in the down-regulation of COMPLEMENT ACTIVATION and its cytolytic sequence.
Enzymes that activate one or more COMPLEMENT PROTEINS in the complement system leading to the formation of the COMPLEMENT MEMBRANE ATTACK COMPLEX, an important response in host defense. They are enzymes in the various COMPLEMENT ACTIVATION pathways.
Compounds that negatively regulate the cascade process of COMPLEMENT ACTIVATION. Uncontrolled complement activation and resulting cell lysis is potentially dangerous for the host.
A screening assay for circulating COMPLEMENT PROTEINS. Diluted SERUM samples are added to antibody-coated ERYTHROCYTES and the percentage of cell lysis is measured. The values are expressed by the so called CH50, in HEMOLYTIC COMPLEMENT units per milliliter, which is the dilution of serum required to lyse 50 percent of the erythrocytes in the assay.
A 63-kDa serum glycoprotein encoded by gene C9. Monomeric C9 (mC9) binds the C5b-8 complex to form C5b-9 which catalyzes the polymerization of C9 forming C5b-p9 (MEMBRANE ATTACK COMPLEX) and transmembrane channels leading to lysis of the target cell. Patients with C9 deficiency suffer from recurrent bacterial infections.
The smaller fragment generated from the cleavage of complement C3 by C3 CONVERTASE. C3a, a 77-amino acid peptide, is a mediator of local inflammatory process. It induces smooth MUSCLE CONTRACTION, and HISTAMINE RELEASE from MAST CELLS and LEUKOCYTES. C3a is considered an anaphylatoxin along with COMPLEMENT C4A; COMPLEMENT C5A; and COMPLEMENT C5A, DES-ARGININE.
Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.
A 206-amino-acid fragment in the alpha chain (672-1663) of C3b. It is generated when C3b is inactivated (iC3b) and its alpha chain is cleaved by COMPLEMENT FACTOR I into C3c (749-954), and C3dg (955-1303) in the presence COMPLEMENT FACTOR H.
Serum proteins that inhibit, antagonize, or inactivate COMPLEMENT C1 or its subunits.
The minor fragment formed when C5 convertase cleaves C5 into C5a and COMPLEMENT C5B. C5a is a 74-amino-acid glycopeptide with a carboxy-terminal ARGININE that is crucial for its spasmogenic activity. Of all the complement-derived anaphylatoxins, C5a is the most potent in mediating immediate hypersensitivity (HYPERSENSITIVITY, IMMEDIATE), smooth MUSCLE CONTRACTION; HISTAMINE RELEASE; and migration of LEUKOCYTES to site of INFLAMMATION.
Proteins that bind to particles and cells to increase susceptibility to PHAGOCYTOSIS, especially ANTIBODIES bound to EPITOPES that attach to FC RECEPTORS. COMPLEMENT C3B may also participate.
The destruction of ERYTHROCYTES by many different causal agents such as antibodies, bacteria, chemicals, temperature, and changes in tonicity.
A 302-amino-acid fragment in the alpha chain (672-1663) of C3b. It is generated when C3b is inactivated (iC3b) and its alpha chain is cleaved by COMPLEMENT FACTOR I into C3c, and C3dg (955-1303) in the presence COMPLEMENT FACTOR H. Serum proteases further degrade C3dg into C3d (1002-1303) and C3g (955-1001).
The natural bactericidal property of BLOOD due to normally occurring antibacterial substances such as beta lysin, leukin, etc. This activity needs to be distinguished from the bactericidal activity contained in a patient's serum as a result of antimicrobial therapy, which is measured by a SERUM BACTERICIDAL TEST.
Molecular sites on or in some B-lymphocytes and macrophages that recognize and combine with COMPLEMENT C3B. The primary structure of these receptors reveal that they contain transmembrane and cytoplasmic domains, with their extracellular portion composed entirely of thirty short consensus repeats each having 60 to 70 amino acids.
Serologic tests based on inactivation of complement by the antigen-antibody complex (stage 1). Binding of free complement can be visualized by addition of a second antigen-antibody system such as red cells and appropriate red cell antibody (hemolysin) requiring complement for its completion (stage 2). Failure of the red cells to lyse indicates that a specific antigen-antibody reaction has taken place in stage 1. If red cells lyse, free complement is present indicating no antigen-antibody reaction occurred in stage 1.
A 77-kDa subcomponent of complement C1, encoded by gene C1S, is a SERINE PROTEASE existing as a proenzyme (homodimer) in the intact complement C1 complex. Upon the binding of COMPLEMENT C1Q to antibodies, the activated COMPLEMENT C1R cleaves C1s into two chains, A (heavy) and B (light, the serine protease), linked by disulfide bonds yielding the active C1s. The activated C1s, in turn, cleaves COMPLEMENT C2 and COMPLEMENT C4 to form C4b2a (CLASSICAL C3 CONVERTASE).
A plasma serine proteinase that cleaves the alpha-chains of C3b and C4b in the presence of the cofactors COMPLEMENT FACTOR H and C4-binding protein, respectively. It is a 66-kDa glycoprotein that converts C3b to inactivated C3b (iC3b) followed by the release of two fragments, C3c (150-kDa) and C3dg (41-kDa). It was formerly called KAF, C3bINF, or enzyme 3b inactivator.
A serum protein that regulates the CLASSICAL COMPLEMENT ACTIVATION PATHWAY. It binds as a cofactor to COMPLEMENT FACTOR I which then hydrolyzes the COMPLEMENT C4B in the CLASSICAL PATHWAY C3 CONVERTASE (C4bC2a).
Zymosan is a polysaccharide derived from the cell walls of Saccharomyces cerevisiae, commonly used in research as an immunostimulant to induce inflammation and study phagocytosis, complement activation, and oxidative burst in neutrophils and macrophages.
Phosphoric acid esters of mannose.
A receptor that is specific for IGF-II and mannose-6-phosphate. The receptor is a 250-kDa single chain polypeptide which is unrelated in structure to the type 1 IGF receptor (RECEPTOR, IGF TYPE 1) and does not have a tyrosine kinase domain.
The engulfing and degradation of microorganisms; other cells that are dead, dying, or pathogenic; and foreign particles by phagocytic cells (PHAGOCYTES).
The smaller fragment formed when complement C4 is cleaved by COMPLEMENT C1S. It is an anaphylatoxin that causes symptoms of immediate hypersensitivity (HYPERSENSITIVITY, IMMEDIATE) but its activity is weaker than that of COMPLEMENT C3A or COMPLEMENT C5A.
The larger fragment generated from the cleavage of C5 by C5 CONVERTASE that yields COMPLEMENT C5A and C5b (beta chain + alpha' chain, the residual alpha chain, bound by disulfide bond). C5b remains bound to the membrane and initiates the spontaneous assembly of the late complement components to form C5b-8-poly-C9, the MEMBRANE ATTACK COMPLEX.
A serine protease that is the complex of COMPLEMENT C3B and COMPLEMENT FACTOR BB. It cleaves multiple COMPLEMENT C3 into COMPLEMENT C3A (anaphylatoxin) and COMPLEMENT C3B in the ALTERNATIVE COMPLEMENT ACTIVATION PATHWAY.

Mannan binding lectin in febrile adults: no correlation with microbial infection and complement activation. (1/88)

AIMS: To study the role of the mannan binding lectin (MBL) pathway of complement activation in the host defence to microbial infection in vivo, and the role of MBL in infectious mortality in non-selected patients. METHODS: A prospective observational study on 177 hospitalised medical patients with new onset fever. The presence, origin, and microbial cause of infection, the circulating MBL and complement activation product 3a (C3a), and the 28 day hospital course were determined. RESULTS: The patients had median MBL values similar to healthy blood donors: 18% of the patients and 14% of the blood donors had MBL deficiency, with values below 0.1 microg/ml. Median C3a was higher in patients with microbiologically confirmed infection than in those without, whereas there was no difference in MBL values or frequency of deficiency among patient groups with or without positive local cultures or bacteraemia. The mortality rate was 8% and the outcome groups did not differ in MBL. In febrile adults hospitalised in internal medicine wards, microbial infection induces complement activation, independently of MBL. CONCLUSIONS: The results argue against a predominant role for the MBL pathway of complement activation and a deficiency of MBL predisposing to serious and invasive microbial infection in non-selected adults.  (+info)

Human mannose-binding lectin and L-ficolin function as specific pattern recognition proteins in the lectin activation pathway of complement. (2/88)

The innate immune response in vertebrates and invertebrates requires the presence of pattern recognition receptors or proteins that recognize microbial cell components including lipopolysaccharide, bacterial peptidoglycan (PGN), and fungal 1,3-beta-D-glucan. We reported previously that PGN and 1,3-beta-D-glucan recognition proteins from insect hemolymph were able to induce the activation of the prophenoloxidase-activating system, one of the major invertebrate innate immune reactions. The goal of this study was to characterize the biochemical properties and effects of the human counterparts of these molecules. Soluble pattern recognition proteins were purified from human serum and identified as human mannose-binding lectin (MBL) and L-ficolin. The use of specific microbial cell component-coupled columns demonstrated that MBL and L-ficolin bind to PGN and 1,3-beta-D-glucan, respectively. Purified MBL and L-ficolin were associated with MBL-associated serine proteases-1 and -2 (MASPs) and small MBL-associated protein as determined by Western blot analysis. Finally, the binding of purified MBL/MASP and L-ficolin/MASP complexes to PGN and 1,3-beta-D-glucan, respectively, resulted in the activation of the lectin-complement pathway. These results indicate that human PGN and 1,3-beta-D-glucan recognition proteins function as complement-activating lectins.  (+info)

Role of mannose-binding lectin in the innate defense against Candida albicans: enhancement of complement activation, but lack of opsonic function, in phagocytosis by human dendritic cells. (3/88)

Mannose-binding lectin (MBL) is a serum collectin believed to be of importance in innate immunity. We have investigated the role of MBL in the first-line defense against Candida albicans, an opportunistic fungal pathogen. MBL bound C. albicans via its lectin domain, resulting in agglutination of the organisms upon their outgrowth of hyphae. In a human in vitro MBL system, deposition of C4 fragments on C. albicans was increased when exogenous MBL was added to serum samples from MBL-deficient individuals. Similar enhancement of deposition of iC3b also was observed. MBL and enhanced opsonic C3 fragments mediated by MBL did not facilitate opsonophagocytosis of the organisms by monocyte-derived dendritic cells (DCs). However, MBL was found to inhibit the growth of C. albicans independently of complement activation, although, with complement activation, further inhibition was observed. We concluded that MBL plays an important role in the first-line defense against C. albicans without the need for opsonophagocytosis by DCs, in which a direct interaction of MBL with C. albicans results in agglutination and accelerated complement activation via the lectin pathway, leading to inhibition of growth.  (+info)

Role of L-ficolin/mannose-binding lectin-associated serine protease complexes in the opsonophagocytosis of type III group B streptococci. (4/88)

Serotype III group B streptococci (GBS) are a common cause of neonatal sepsis and meningitis. Although deficiency in maternal capsular polysaccharide (CPS)-specific IgG correlates with susceptibility of neonates to the GBS infection, serum deficient in CPS-specific IgG mediates significant opsonophagocytosis. This IgG-independent opsonophagocytosis requires activation of the complement pathway, a process requiring the presence of both Ca(2+) and Mg(2+), and is significantly reduced by chelating Ca(2+) with EGTA. In these studies, we defined a role of L-ficolin/mannose-binding lectin-associated serine protease (MASP) complexes in Ca(2+)-dependent, Ab-independent opsonophagocytosis of serotype III GBS. Incubation of GBS with affinity-purified L-ficolin/MASP complexes and C1q-depleted serum deficient in CPS-specific Ab supported opsonophagocytic killing, and this killing was inhibited by fluid-phase N-acetylglucosamine, the ligand for L-ficolin. Binding of L-ficolin was proportional to the CPS content of individual strains, and opsonophagocytic killing and C4 activation were inhibited by fluid-phase CPS, suggesting that L-ficolin binds to CPS. Sialic acid is known to inhibit alternative complement pathway activation, and, as expected, the bactericidal index (percentage of bacteria killed) for individual strains was inversely proportional to the sialic acid content of the CPS, and L-ficolin-initiated opsonophagocytic killing was significantly increased by addition of CPS-specific IgG2, which increased activation of the alternative pathway. We conclude that binding of L-ficolin/MASP complexes to the CPS generates C3 convertase C4b2a, which deposits C3b on GBS. C3b deposited by this lectin pathway forms alternative pathway C3 convertase C3bBb whose activity is enhanced by CPS-specific IgG2, leading to increased opsonophagocytic killing by further deposition of C3b on the GBS.  (+info)

Deficiency of the mannan-binding lectin pathway of complement and poor outcome in cystic fibrosis: bacterial colonization may be decisive for a relationship. (5/88)

In cystic fibrosis (CF) prognosis concerning lung damage development is highly variable and difficult to predict. Mannan-binding lectin (MBL) deficiency has been reported to be associated with poor outcome in CF lung disease. MBL is a recognition molecule of the MBL pathway of the complement system and is encoded by a gene characterized by a high degree of polymorphism. Some genotypes result in low serum concentrations of MBL. MBL-associated serine protease 2 (MASP-2) is another protein belonging to the MBL pathway. A mutation resulting in low levels of MASP-2 in serum has been described recently. In the present study, 112 CF patients aged 4-54 years were investigated for MBL and MASP-2 genotypes, serum levels of MBL and MASP-2 and the MBL pathway function in serum. No correlation to reduced lung function or need for lung transplantation was seen, either for MBL deficiency, MASP-2 gene mutation or reduced MBL pathway function. However, in the 27 patients colonized with Staphylococcus aureus, MBL-deficient genotypes were associated with decreased lung function. As expected, MBL pathway function in serum was reduced both in MBL-deficient patients and in patients carrying a mutant MASP-2 allele. An unexpected finding was that CF patients had higher serum levels of MBL than healthy controls when corrected for MBL genotype. In conclusion, MBL pathway function was affected both by MBL and by MASP-2 genotypes. However, MBL or MASP-2 levels in serum did not affect the clinical outcome in the cohort of CF patients studied.  (+info)

Composition of the lectin pathway of complement in Gallus gallus: absence of mannan-binding lectin-associated serine protease-1 in birds. (6/88)

The lectin pathway of complement is activated by multimolecular complexes that recognize and bind to microbial polysaccharides. These complexes comprise a multimeric carbohydrate recognition subunit (either mannan-binding lectin (MBL) or a ficolin), three MBL-associated serine proteases (MASP-1, -2, and -3), and MAp19 (a truncated product of the MASP-2 gene). In this study we report the cloning of chicken MASP-2, MASP-3, and MAp19 and the organization of their genes and those for chicken MBL and a novel ficolin. Mammals usually possess two MBL genes and two or three ficolin genes, but chickens have only one of each, both of which represent the undiversified ancestors of the mammalian genes. The primary structure of chicken MASP-2 is 54% identical with those of the human and mouse MASP-2, and the organization of its gene is the same as in mammals. MASP-3 is even more conserved; chicken MASP-3 shares approximately 75% of its residues with human and Xenopus MASP-3. It is more widely expressed than other lectin pathway components, suggesting a possible function of MASP-3 different from those of the other components. In mammals, MASP-1 and MASP-3 are alternatively spliced products of a single structural gene. We demonstrate the absence of MASP-1 in birds, possibly caused by the loss of MASP-1-specific exons during phylogeny. Despite the lack of MASP-1-like enzymatic activity in sera of chicken and other birds, avian lectin pathway complexes efficiently activate C4.  (+info)

Gastrointestinal ischemia-reperfusion injury is lectin complement pathway dependent without involving C1q. (7/88)

Complement activation plays an important role in local and remote tissue injury associated with gastrointestinal ischemia-reperfusion (GI/R). The role of the classical and lectin complement pathways in GI/R injury was evaluated using C1q-deficient (C1q KO), MBL-A/C-deficient (MBL-null), complement factor 2- and factor B-deficient (C2/fB KO), and wild-type (WT) mice. Gastrointestinal ischemia (20 min), followed by 3-h reperfusion, induced intestinal and lung injury in C1q KO and WT mice, but not in C2/fB KO mice. Addition of human C2 to C2/fB KO mice significantly restored GI/R injury, demonstrating that GI/R injury is mediated via the lectin and/or classical pathway. Tissue C3 deposition in C1q KO and WT, but not C2/fB KO, mice after GI/R demonstrated that complement was activated in C1q KO mice. GI/R significantly increased serum alanine aminotransferase, gastrointestinal barrier dysfunction, and neutrophil infiltration into the lung and gut in C1q KO and WT, but not C2/fB KO, mice. MBL-null mice displayed little gut injury after GI/R, but lung injury was present. Addition of recombinant human MBL (rhuMBL) to MBL-null mice significantly increased injury compared with MBL-null mice after GI/R and was reversed by anti-MBL mAb treatment. However, MBL-null mice were not protected from secondary lung injury after GI/R. These data demonstrate that C2 and MBL, but not C1q, are necessary for gut injury after GI/R. Lung injury in mice after GI/R is MBL and C1q independent, but C2 dependent, suggesting a potential role for ficolins in this model.  (+info)

Mannose-binding lectin is a regulator of inflammation that accompanies myocardial ischemia and reperfusion injury. (8/88)

The mannose-binding lectin (MBL), a circulating pattern recognition molecule, recognizes a wide range of infectious agents with resultant initiation of the complement cascade in an Ab-independent manner. MBL recognizes infectious non-self and altered self in the guise of apoptotic and necrotic cells. In this study, we demonstrate that mice lacking MBL, and hence are devoid of MBL-dependent lectin pathway activation but have fully active alternative and classical complement pathways, are protected from cardiac reperfusion injury with resultant preservation of cardiac function. Significantly, mice that lack a major component of the classical complement pathway initiation complex (C1q) but have an intact MBL complement pathway, are not protected from injury. These results suggest that the MBL-dependent pathway of complement activation is a key regulator of myocardial reperfusion ischemic injury. MBL is an example of a pattern recognition molecule that plays a dual role in modifying inflammatory responses to sterile and infectious injury.  (+info)

Mannose-Binding Lectin (MBL) is a protein that belongs to the collectin family and plays a crucial role in the innate immune system. It's primarily produced by the liver and secreted into the bloodstream. MBL binds to carbohydrate structures, such as mannose, found on the surface of various microorganisms, including bacteria, viruses, fungi, and parasites.

Once MBL binds to these microorganisms, it activates the complement system through the lectin pathway, which leads to the destruction of the pathogens by opsonization (marking for phagocytosis) or direct lysis. Additionally, MBL can also initiate other immune responses, such as inflammation and immune cell activation, helping to protect the host from infections.

Deficiencies in MBL have been associated with increased susceptibility to certain infectious diseases, autoimmune disorders, and allergies. However, more research is needed to fully understand the complex role of MBL in human health and disease.

Collectins are a group of proteins that belong to the collectin family, which are involved in the innate immune system. They are composed of a collagen-like region and a carbohydrate recognition domain (CRD), which allows them to bind to specific sugars on the surface of microorganisms, cells, and particles. Collectins play a crucial role in the defense against pathogens by promoting the clearance of microbes, modulating inflammation, and regulating immune responses.

Some examples of collectins include:

* Surfactant protein A (SP-A) and surfactant protein D (SP-D), which are found in the lungs and help to maintain the stability of the lung lining and protect against respiratory infections.
* Mannose-binding lectin (MBL), which is a serum protein that binds to mannose sugars on the surface of microorganisms, activating the complement system and promoting phagocytosis.
* Collectin liver 1 (CL-L1) and collectin kidney 1 (CL-K1), which are found in the liver and kidneys, respectively, and play a role in the clearance of apoptotic cells and immune complexes.

Deficiencies or mutations in collectins can lead to increased susceptibility to infections, autoimmune diseases, and other disorders.

The Mannose-Binding Lectin (MBL) pathway is a part of the complement system, which is a group of proteins that play a crucial role in the body's immune defense against infectious agents. The MBL pathway is an alternative activation pathway of the complement system, which can be initiated without the need for antibodies.

MBL is a protein found in blood plasma and other bodily fluids. It recognizes and binds to specific sugars (mannose and fucose) found on the surface of many microorganisms, including bacteria, viruses, fungi, and parasites. When MBL binds to these sugars, it triggers a series of proteolytic cleavage events that activate the complement components C4 and C2, forming the C3 convertase (C4b2a).

The C3 convertase then cleaves the complement component C3 into C3a and C3b. C3b can bind to the surface of microorganisms, leading to their opsonization (coating) and subsequent phagocytosis by immune cells. Additionally, C3b can also trigger the formation of the membrane attack complex (MAC), which creates a pore in the membrane of microorganisms, leading to their lysis and death.

Overall, the MBL pathway plays an essential role in innate immunity, providing a rapid and effective defense against invading microorganisms.

Mannose is a simple sugar (monosaccharide) that is similar in structure to glucose. It is a hexose, meaning it contains six carbon atoms. Mannose is a stereoisomer of glucose, meaning it has the same chemical formula but a different structural arrangement of its atoms.

Mannose is not as commonly found in foods as other simple sugars, but it can be found in some fruits, such as cranberries, blueberries, and peaches, as well as in certain vegetables, like sweet potatoes and turnips. It is also found in some dietary fibers, such as those found in beans and whole grains.

In the body, mannose can be metabolized and used for energy, but it is also an important component of various glycoproteins and glycolipids, which are molecules that play critical roles in many biological processes, including cell recognition, signaling, and adhesion.

Mannose has been studied as a potential therapeutic agent for various medical conditions, including urinary tract infections (UTIs), because it can inhibit the attachment of certain bacteria to the cells lining the urinary tract. Additionally, mannose-binding lectins have been investigated for their potential role in the immune response to viral and bacterial infections.

The alternative complement pathway is one of the three initiating pathways of the complement system, which is a part of the innate immune system that helps to clear pathogens and damaged cells from the body. The other two pathways are the classical and lectin pathways.

The alternative pathway is continuously activated at a low level, even in the absence of infection or injury, through the spontaneous cleavage of complement component C3 into C3a and C3b by the protease factor D in the presence of magnesium ions. The generated C3b can then bind covalently to nearby surfaces, including pathogens and host cells.

On self-surfaces, regulatory proteins like decay-accelerating factor (DAF) or complement receptor 1 (CR1) help to prevent the formation of the alternative pathway convertase and thus further activation of the complement system. However, on foreign surfaces, the C3b can recruit more complement components, forming a complex called the alternative pathway convertase (C3bBb), which cleaves additional C3 molecules into C3a and C3b.

The generated C3b can then bind to the surface and participate in the formation of the membrane attack complex (MAC), leading to the lysis of the target cell. The alternative pathway plays a crucial role in the defense against gram-negative bacteria, fungi, and parasites, as well as in the clearance of immune complexes and apoptotic cells. Dysregulation of the alternative complement pathway has been implicated in several diseases, including autoimmune disorders and atypical hemolytic uremic syndrome (aHUS).

The "Classical Complement Pathway" is one of the three pathways that make up the complement system, which is a part of the immune system in humans and other animals. The complement system helps to enhance the ability of antibodies and phagocytic cells to clear pathogens from the body.

The Classical Complement Pathway is initiated by the binding of the first component of the complement system, C1, to an activator surface, such as an antigen-antibody complex. Activation of C1 results in the sequential activation of other components of the complement system, including C4 and C2, which form the C3 convertase (C4b2a). The C3 convertase cleaves the third component of the complement system, C3, into C3a and C3b. C3b then binds to the activator surface and forms a complex with other components of the complement system, leading to the formation of the membrane attack complex (MAC), which creates a pore in the membrane of the target cell, causing its lysis.

The Classical Complement Pathway plays an important role in the immune response to pathogens and can also contribute to inflammation and tissue damage in certain diseases, such as autoimmune disorders and allergies.

Mannose-binding lectins (MBLs) are a group of proteins that belong to the collectin family and play a crucial role in the innate immune system. They are primarily produced by the liver and secreted into the bloodstream. MBLs have a specific affinity for mannose sugar residues found on the surface of various microorganisms, including bacteria, viruses, fungi, and parasites.

The primary function of MBLs is to recognize and bind to these mannose-rich structures, which triggers the complement system's activation through the lectin pathway. This process leads to the destruction of the microorganism by opsonization (coating the microbe to enhance phagocytosis) or direct lysis. MBLs also have the ability to neutralize certain viruses and inhibit the replication of others, further contributing to their antimicrobial activity.

Deficiencies in MBL levels or function have been associated with an increased susceptibility to infections, particularly in children and older adults. However, the clinical significance of MBL deficiency remains a subject of ongoing research.

Lectins are a type of proteins that bind specifically to carbohydrates and have been found in various plant and animal sources. They play important roles in biological recognition events, such as cell-cell adhesion, and can also be involved in the immune response. Some lectins can agglutinate certain types of cells or precipitate glycoproteins, while others may have a more direct effect on cellular processes. In some cases, lectins from plants can cause adverse effects in humans if ingested, such as digestive discomfort or allergic reactions.

Complement activation is the process by which the complement system, a part of the immune system, is activated to help eliminate pathogens and damaged cells from the body. The complement system consists of a group of proteins that work together to recognize and destroy foreign substances.

Activation of the complement system can occur through three different pathways: the classical pathway, the lectin pathway, and the alternative pathway. Each pathway involves a series of proteolytic reactions that ultimately result in the formation of the membrane attack complex (MAC), which creates a pore in the membrane of the target cell, leading to its lysis and removal.

The classical pathway is typically activated by the binding of antibodies to antigens on the surface of a pathogen or damaged cell. The lectin pathway is activated by the recognition of specific carbohydrate structures on the surface of microorganisms. The alternative pathway can be spontaneously activated and serves as an amplification loop for both the classical and lectin pathways.

Complement activation plays a crucial role in the immune response, but uncontrolled or excessive activation can also lead to tissue damage and inflammation. Dysregulation of complement activation has been implicated in various diseases, including autoimmune disorders, inflammatory conditions, and neurodegenerative diseases.

Genotype, in genetics, refers to the complete heritable genetic makeup of an individual organism, including all of its genes. It is the set of instructions contained in an organism's DNA for the development and function of that organism. The genotype is the basis for an individual's inherited traits, and it can be contrasted with an individual's phenotype, which refers to the observable physical or biochemical characteristics of an organism that result from the expression of its genes in combination with environmental influences.

It is important to note that an individual's genotype is not necessarily identical to their genetic sequence. Some genes have multiple forms called alleles, and an individual may inherit different alleles for a given gene from each parent. The combination of alleles that an individual inherits for a particular gene is known as their genotype for that gene.

Understanding an individual's genotype can provide important information about their susceptibility to certain diseases, their response to drugs and other treatments, and their risk of passing on inherited genetic disorders to their offspring.

Complement C3 is a protein that plays a central role in the complement system, which is a part of the immune system that helps to clear pathogens and damaged cells from the body. Complement C3 can be activated through three different pathways: the classical pathway, the lectin pathway, and the alternative pathway. Once activated, it breaks down into two fragments, C3a and C3b.

C3a is an anaphylatoxin that helps to recruit immune cells to the site of infection or injury, while C3b plays a role in opsonization, which is the process of coating pathogens or damaged cells with proteins to make them more recognizable to the immune system. Additionally, C3b can also activate the membrane attack complex (MAC), which forms a pore in the membrane of target cells leading to their lysis or destruction.

In summary, Complement C3 is an important protein in the complement system that helps to identify and eliminate pathogens and damaged cells from the body through various mechanisms.

Complement C1q is a protein that is part of the complement system, which is a group of proteins in the blood that help to eliminate pathogens and damaged cells from the body. C1q is the first component of the classical complement pathway, which is activated by the binding of C1q to antibodies that are attached to the surface of a pathogen or damaged cell.

C1q is composed of six identical polypeptide chains, each containing a collagen-like region and a globular head region. The globular heads can bind to various structures, including the Fc regions of certain antibodies, immune complexes, and some types of cells. When C1q binds to an activating surface, it triggers a series of proteolytic reactions that lead to the activation of other complement components and the formation of the membrane attack complex (MAC), which can punch holes in the membranes of pathogens or damaged cells, leading to their destruction.

In addition to its role in the immune system, C1q has also been found to have roles in various physiological processes, including tissue remodeling, angiogenesis, and the clearance of apoptotic cells. Dysregulation of the complement system, including abnormalities in C1q function, has been implicated in a variety of diseases, including autoimmune disorders, inflammatory diseases, and neurodegenerative conditions.

Genetic polymorphism refers to the occurrence of multiple forms (called alleles) of a particular gene within a population. These variations in the DNA sequence do not generally affect the function or survival of the organism, but they can contribute to differences in traits among individuals. Genetic polymorphisms can be caused by single nucleotide changes (SNPs), insertions or deletions of DNA segments, or other types of genetic rearrangements. They are important for understanding genetic diversity and evolution, as well as for identifying genetic factors that may contribute to disease susceptibility in humans.

Galectins are a family of animal lectins (carbohydrate-binding proteins) that bind specifically to beta-galactosides. They play important roles in various biological processes, including inflammation, immune response, cancer progression, and development. Galectins are widely distributed in various tissues and organ systems, and they can be found both intracellularly and extracellularly.

There are 15 known mammalian galectins, which are classified into three groups based on their structure: prototype (Gal-1, -2, -5, -7, -10, -13, -14, and -16), chimera-type (Gal-3), and tandem-repeat type (Gal-4, -6, -8, -9, and -12). Each galectin has a unique set of functions, but they often work together to regulate cellular processes.

Abnormal expression or function of galectins has been implicated in various diseases, including cancer, fibrosis, and autoimmune disorders. Therefore, galectins are considered potential targets for the development of new therapeutic strategies.

The complement system is a group of proteins found in the blood and on the surface of cells that when activated, work together to help eliminate pathogens such as bacteria, viruses, and fungi from the body. The proteins are normally inactive in the bloodstream. When they encounter an invading microorganism or foreign substance, a series of reactions take place leading to the activation of the complement system. Activation results in the production of effector molecules that can punch holes in the cell membranes of pathogens, recruit and activate immune cells, and help remove debris and dead cells from the body.

There are three main pathways that can lead to complement activation: the classical pathway, the lectin pathway, and the alternative pathway. Each pathway involves a series of proteins that work together in a cascade-like manner to amplify the response and generate effector molecules. The three main effector molecules produced by the complement system are C3b, C4b, and C5b. These molecules can bind to the surface of pathogens, marking them for destruction by other immune cells.

Complement proteins also play a role in the regulation of the immune response. They help to prevent excessive activation of the complement system, which could damage host tissues. Dysregulation of the complement system has been implicated in a number of diseases, including autoimmune disorders and inflammatory conditions.

In summary, Complement System Proteins are a group of proteins that play a crucial role in the immune response by helping to eliminate pathogens and regulate the immune response. They can be activated through three different pathways, leading to the production of effector molecules that mark pathogens for destruction. Dysregulation of the complement system has been linked to various diseases.

Complement C4 is a protein that plays a crucial role in the complement system, which is a part of the immune system that helps to clear pathogens and damaged cells from the body. Complement C4 is involved in the early stages of the complement activation cascade, where it helps to identify and tag foreign or abnormal cells for destruction by other components of the immune system.

Specifically, Complement C4 can be cleaved into two smaller proteins, C4a and C4b, during the complement activation process. C4b then binds to the surface of the target cell and helps to initiate the formation of the membrane attack complex (MAC), which creates a pore in the cell membrane and leads to lysis or destruction of the target cell.

Deficiencies or mutations in the Complement C4 gene can lead to various immune disorders, including certain forms of autoimmune diseases and susceptibility to certain infections.

Genetic predisposition to disease refers to an increased susceptibility or vulnerability to develop a particular illness or condition due to inheriting specific genetic variations or mutations from one's parents. These genetic factors can make it more likely for an individual to develop a certain disease, but it does not guarantee that the person will definitely get the disease. Environmental factors, lifestyle choices, and interactions between genes also play crucial roles in determining if a genetically predisposed person will actually develop the disease. It is essential to understand that having a genetic predisposition only implies a higher risk, not an inevitable outcome.

Mannose-binding protein-associated serine proteases (MASPs) are a group of enzymes that are associated with mannose-binding lectin (MBL), a protein involved in the innate immune system's response to pathogens. MASPs are responsible for activating the complement system, which is a part of the immune system that helps to eliminate pathogens and damaged cells from the body.

MASPs are proteases, meaning they cleave other proteins at specific sites. There are two main types of MASPs, MASP-1 and MASP-2, which are activated by the binding of MBL to carbohydrate structures on the surface of pathogens. Once activated, MASP-1 and MASP-2 cleave complement components C4 and C2, leading to the formation of the C3 convertase enzyme complex, which ultimately results in the activation of the complement system.

MASPs have also been shown to play a role in other physiological processes, such as tissue remodeling and inflammation. Mutations in MASP genes have been associated with various immune disorders, including recurrent infections, autoimmune diseases, and inflammatory conditions.

Complement Factor B is a protein that plays a crucial role in the complement system, which is a part of the immune system that helps to eliminate pathogens and damaged cells from the body. Specifically, Factor B is a component of the alternative pathway of the complement system, which provides a rapid and amplified response to microbial surfaces.

Factor B is cleaved by another protease called Factor D into two fragments, Ba and Bb. The formation of the C3 convertase (C3bBb) is essential for the activation of the alternative pathway. This complex can cleave and activate more C3 molecules, leading to a cascade of reactions that result in the formation of the membrane attack complex (MAC), which forms pores in the membranes of target cells, causing their lysis and elimination.

Deficiencies or mutations in Complement Factor B can lead to various complement-mediated diseases, such as atypical hemolytic uremic syndrome (aHUS) and age-related macular degeneration (AMD).

Plant lectins are proteins or glycoproteins that are abundantly found in various plant parts such as seeds, leaves, stems, and roots. They have the ability to bind specifically to carbohydrate structures present on cell membranes, known as glycoconjugates. This binding property of lectins is reversible and non-catalytic, meaning it does not involve any enzymatic activity.

Lectins play several roles in plants, including defense against predators, pathogens, and herbivores. They can agglutinate red blood cells, stimulate the immune system, and have been implicated in various biological processes such as cell growth, differentiation, and apoptosis (programmed cell death). Some lectins also exhibit mitogenic activity, which means they can stimulate the proliferation of certain types of cells.

In the medical field, plant lectins have gained attention due to their potential therapeutic applications. For instance, some lectins have been shown to possess anti-cancer properties and are being investigated as potential cancer treatments. However, it is important to note that some lectins can be toxic or allergenic to humans and animals, so they must be used with caution.

Complement C2 is a protein that plays a crucial role in the complement system, which is a part of the immune system that helps to eliminate pathogens and damaged cells from the body. Specifically, C2 is a component of the classical complement pathway, which is activated by the binding of antibodies to antigens on the surface of foreign particles or cells.

When the classical pathway is activated, C2 is cleaved into two fragments: C2a and C2b. C2a then binds to C4b to form the C3 convertase (C4b2a), which cleaves C3 into C3a and C3b. C3b can then go on to form the membrane attack complex, which creates a pore in the membrane of the target cell, leading to its lysis.

In summary, Complement C2 is a protein that helps to activate the complement system and destroy foreign particles or cells through the formation of the C3 convertase and the membrane attack complex.

Carrier proteins, also known as transport proteins, are a type of protein that facilitates the movement of molecules across cell membranes. They are responsible for the selective and active transport of ions, sugars, amino acids, and other molecules from one side of the membrane to the other, against their concentration gradient. This process requires energy, usually in the form of ATP (adenosine triphosphate).

Carrier proteins have a specific binding site for the molecule they transport, and undergo conformational changes upon binding, which allows them to move the molecule across the membrane. Once the molecule has been transported, the carrier protein returns to its original conformation, ready to bind and transport another molecule.

Carrier proteins play a crucial role in maintaining the balance of ions and other molecules inside and outside of cells, and are essential for many physiological processes, including nerve impulse transmission, muscle contraction, and nutrient uptake.

Complement C3b is a protein fragment that plays a crucial role in the complement system, which is a part of the immune system that helps to clear pathogens and damaged cells from the body. C3b is generated during the activation of the complement system, particularly via the classical, lectin, and alternative pathways.

Once formed, C3b can bind covalently to the surface of microbes or other target particles, marking them for destruction by other components of the immune system. Additionally, C3b can interact with other proteins in the complement system to generate the membrane attack complex (MAC), which forms pores in the membranes of targeted cells, leading to their lysis and removal.

In summary, Complement C3b is a vital protein fragment involved in the recognition, tagging, and elimination of pathogens and damaged cells during the immune response.

Complement C1 is a protein complex that plays a crucial role in the complement system, which is a part of the immune system that helps to eliminate pathogens and damaged cells from the body. The complement system consists of a group of proteins that work together to destroy microbes and remove debris.

Complement C1 is composed of three subunits: C1q, C1r, and C1s. When activated, C1q binds to the surface of a pathogen or damaged cell, leading to the activation of C1r and C1s. Activated C1r then cleaves and activates C1s, which in turn cleaves and activates other complement components, ultimately resulting in the formation of the membrane attack complex (MAC), a protein structure that forms a pore in the membrane of the target cell, leading to its lysis and destruction.

Defects in the complement component C1 can lead to immune disorders, such as hereditary angioedema, which is characterized by recurrent episodes of swelling in various parts of the body.

Galectin-3 is a type of protein belonging to the galectin family, which binds to carbohydrates (sugars) and plays a role in various biological processes such as inflammation, immune response, and cancer. It is also known as Mac-2 binding protein or LGALS3.

Galectin-3 is unique among galectins because it can form oligomers (complexes of multiple subunits) and has a wide range of functions in the body. It is involved in cell adhesion, proliferation, differentiation, apoptosis (programmed cell death), and angiogenesis (formation of new blood vessels).

In the context of disease, Galectin-3 has been implicated in several pathological conditions such as fibrosis, heart failure, and cancer. High levels of Galectin-3 have been associated with poor prognosis in patients with heart failure, and it is considered a potential biomarker for this condition. In addition, Galectin-3 has been shown to promote tumor growth, angiogenesis, and metastasis, making it a target for cancer therapy.

Complement C5 is a protein that plays a crucial role in the complement system, which is a part of the immune system that helps to eliminate pathogens and damaged cells from the body. The complement system is a complex series of biochemical reactions that help to identify and destroy foreign substances, such as bacteria and viruses.

Complement C5 is one of several proteins in the complement system that are activated in a cascading manner in response to an activating event, such as the binding of an antibody to a pathogen. Once activated, Complement C5 can be cleaved into two smaller proteins, C5a and C5b.

C5a is a powerful anaphylatoxin, which means it can cause the release of histamine from mast cells and basophils, leading to inflammation and increased vascular permeability. It also acts as a chemoattractant, drawing immune cells to the site of infection or injury.

C5b, on the other hand, plays a role in the formation of the membrane attack complex (MAC), which is a protein structure that can punch holes in the membranes of pathogens, leading to their lysis and destruction.

Overall, Complement C5 is an important component of the immune system's response to infection and injury, helping to eliminate pathogens and damaged cells from the body.

Complement inactivator proteins are a group of regulatory proteins that help to control and limit the activation of the complement system, which is a part of the immune system. The complement system is a complex series of biochemical reactions that help to eliminate pathogens and damaged cells from the body. However, if not properly regulated, the complement system can also cause damage to healthy tissues and contribute to the development of various diseases.

Complement inactivator proteins work by inhibiting specific components of the complement system, preventing them from activating and causing an immune response. Some examples of complement inactivator proteins include:

1. C1 inhibitor (C1INH): This protein regulates the activation of the classical pathway of the complement system by inhibiting the C1 complex, which is a group of proteins that initiate this pathway.
2. Decay-accelerating factor (DAF or CD55): This protein regulates the activation of both the classical and alternative pathways of the complement system by accelerating the decay of the C3/C5 convertases, which are enzymes that activate the complement components C3 and C5.
3. Membrane cofactor protein (MCP or CD46): This protein regulates the activation of the alternative pathway of the complement system by serving as a cofactor for the cleavage and inactivation of C3b, a component of the C3 convertase.
4. Factor H: This protein also regulates the activation of the alternative pathway of the complement system by acting as a cofactor for the cleavage and inactivation of C3b, and by preventing the formation of the C3 convertase.

Deficiencies or dysfunction of complement inactivator proteins can lead to various diseases, including hereditary angioedema (C1INH deficiency), atypical hemolytic uremic syndrome (factor H deficiency or dysfunction), and age-related macular degeneration (complement component overactivation).

Complement Factor D is a protein that plays a crucial role in the complement system, which is a part of the immune system that helps to clear pathogens and damaged cells from the body. Specifically, Factor D is a serine protease that is involved in the alternative pathway of the complement system.

In this pathway, Factor D helps to cleave another protein called Factor B, which then activates a complex called the C3 convertase. The C3 convertase cleaves complement component 3 (C3) into C3a and C3b, leading to the formation of the membrane attack complex (MAC), which creates a pore in the membrane of the target cell, causing its lysis and removal from the body.

Deficiencies or mutations in Complement Factor D can lead to an impaired alternative pathway and increased susceptibility to certain infections, particularly those caused by Neisseria bacteria. Additionally, abnormal regulation of the complement system has been implicated in a variety of diseases, including autoimmune disorders, inflammatory conditions, and neurodegenerative diseases.

Complement C3-C5 convertases are proteins that play a crucial role in the activation of the complement system, which is a part of the immune system. The complement system helps to eliminate pathogens and damaged cells from the body by marking them for destruction and attracting immune cells to the site of infection or injury.

The C3-C5 convertases are formed during the activation of the complement component 3 (C3) protein, which is a central player in the complement system. The formation of the C3-C5 convertase involves two main steps:

1. C3 convertase formation: In this step, a complex of proteins called the C3 convertase is formed by the cleavage of C3 into C3a and C3b fragments. This complex can then cleave additional C3 molecules into C3a and C3b fragments, amplifying the complement response.
2. C5 convertase formation: In this step, the C3b fragment from the C3 convertase binds to another protein called C4b2a, forming a new complex called the C5 convertase. The C5 convertase can then cleave the C5 protein into C5a and C5b fragments.

The C5b fragment goes on to form the membrane attack complex (MAC), which creates a pore in the membrane of the target cell, leading to its lysis or destruction. The C3a and C5a fragments are small proteins called anaphylatoxins that can cause inflammation and attract immune cells to the site of infection or injury.

Overall, the formation of Complement C3-C5 convertases is a critical step in the activation of the complement system and plays a key role in the body's defense against pathogens and damaged cells.

Properdin is defined as a positive regulatory protein in the complement system, which is a part of the immune system. It plays a crucial role in the alternative pathway of complement activation. Properdin stabilizes the C3 convertase (C3bBb), preventing its decay and increasing the efficiency of the alternative pathway. This results in the production of the membrane attack complex, which leads to the lysis of foreign cells or pathogens. Deficiencies in properdin can lead to an increased susceptibility to bacterial infections.

Complement receptors are proteins found on the surface of various cells in the human body, including immune cells and some non-immune cells. They play a crucial role in the complement system, which is a part of the innate immune response that helps to eliminate pathogens and damaged cells from the body. Complement receptors bind to complement proteins or fragments that are generated during the activation of the complement system. This binding triggers various intracellular signaling events that can lead to diverse cellular responses, such as phagocytosis, inflammation, and immune regulation.

There are several types of complement receptors, including:

1. CR1 (CD35): A receptor found on erythrocytes, B cells, neutrophils, monocytes, macrophages, and glomerular podocytes. It functions in the clearance of immune complexes and regulates complement activation.
2. CR2 (CD21): Expressed mainly on B cells and follicular dendritic cells. It facilitates antigen presentation, B-cell activation, and immune regulation.
3. CR3 (CD11b/CD18, Mac-1): Present on neutrophils, monocytes, macrophages, and some T cells. It mediates cell adhesion, phagocytosis, and intracellular signaling.
4. CR4 (CD11c/CD18, p150,95): Expressed on neutrophils, monocytes, macrophages, and dendritic cells. It is involved in cell adhesion, phagocytosis, and intracellular signaling.
5. C5aR (CD88): Found on various immune cells, including neutrophils, monocytes, macrophages, mast cells, eosinophils, and dendritic cells. It binds to the complement protein C5a and mediates chemotaxis, degranulation, and inflammation.
6. C5L2 (GPR77): Present on various cell types, including immune cells. Its function is not well understood but may involve regulating C5a-mediated responses or acting as a receptor for other ligands.

These receptors play crucial roles in the immune response and inflammation by mediating various functions such as chemotaxis, phagocytosis, cell adhesion, and intracellular signaling. Dysregulation of these receptors has been implicated in several diseases, including autoimmune disorders, infections, and cancer.

Complement Factor H is a protein involved in the regulation of the complement system, which is a part of the immune system that helps to clear pathogens and damaged cells from the body. Specifically, Complement Factor H helps to regulate the activation and deactivation of the complement component C3b, preventing excessive or unwanted activation of the complement system and protecting host tissues from damage.

Complement Factor H is a crucial protein in maintaining the balance between the protective effects of the complement system and the potential for harm to the body's own cells and tissues. Deficiencies or mutations in Complement Factor H have been associated with several diseases, including age-related macular degeneration (AMD), atypical hemolytic uremic syndrome (aHUS), and C3 glomerulopathy.

The Complement Membrane Attack Complex (MAC), also known as the Terminal Complement Complex (TCC), is a protein structure that forms in the final stages of the complement system's immune response. The complement system is a part of the innate immune system that helps to eliminate pathogens and damaged cells from the body.

The MAC is composed of several proteins, including C5b, C6, C7, C8, and multiple subunits of C9, which assemble on the surface of target cells. The formation of the MAC creates a pore-like structure in the cell membrane, leading to disruption of the membrane's integrity and ultimately causing cell lysis or damage.

The MAC plays an important role in the immune response by helping to eliminate pathogens that have evaded other immune defenses. However, uncontrolled activation of the complement system and formation of the MAC can also contribute to tissue damage and inflammation in various diseases, such as autoimmune disorders, age-related macular degeneration, and ischemia-reperfusion injury.

Complement C4b is a protein fragment that is formed during the activation of the complement system, which is a part of the immune system. The complement system helps to eliminate pathogens and damaged cells from the body by tagging them for destruction and attracting immune cells to the site of infection or injury.

C4b is generated when the C4 protein is cleaved into two smaller fragments, C4a and C4b, during the activation of the classical or lectin pathways of the complement system. C4b then binds covalently to the surface of the target cell or pathogen, forming a complex with other complement proteins that can create a membrane attack complex (MAC) and cause cell lysis.

C4b can also act as an opsonin, coating the surface of the target cell or pathogen and making it easier for immune cells to recognize and phagocytose them. Additionally, C4b can activate the alternative pathway of the complement system, leading to further amplification of the complement response.

Complement C6 is a protein that plays a crucial role in the complement system, which is a part of the immune system that helps to eliminate pathogens and damaged cells from the body. Specifically, C6 is a component of the membrane attack complex (MAC), which is a group of proteins that work together to form a pore in the membrane of target cells, leading to their lysis or destruction.

The complement system is activated through several different pathways, including the classical pathway, the lectin pathway, and the alternative pathway. Once activated, these pathways converge at the level of C3, which is cleaved into C3a and C3b fragments. C3b can then bind to the surface of target cells and initiate the formation of the MAC.

C6 is one of several proteins that are required for the formation of the MAC. When C6 binds to C7, it undergoes a conformational change that allows it to interact with C8 and form a stable complex. This complex then recruits additional C9 molecules, which polymerize to form the pore in the target cell membrane.

Deficiencies in complement components, including C6, can lead to increased susceptibility to certain types of infections, as well as autoimmune disorders and other medical conditions.

Complement C3b inactivator proteins, also known as complement regulators or decay-accelerating factor (DAF), are a group of proteins that play a crucial role in regulating the complement system. The complement system is a part of the immune system that helps to eliminate pathogens and damaged cells from the body.

The complement C3b inactivator proteins include two main types: complement receptor 1 (CR1) and decay-accelerating factor (DAF). These proteins work by regulating the formation of the membrane attack complex (MAC), a protein structure that forms pores in the cell membrane, leading to cell lysis.

Complement C3b inactivator proteins bind to C3b and C4b components of the complement system, preventing them from forming the MAC. By doing so, they help to prevent excessive activation of the complement system, which can damage healthy cells and tissues.

Deficiencies or dysfunction of complement C3b inactivator proteins have been associated with several diseases, including autoimmune disorders, inflammatory diseases, and infectious diseases. Therefore, understanding the role of these proteins in regulating the complement system is essential for developing new therapies to treat these conditions.

Complement activating enzymes are proteins that play a crucial role in the activation of the complement system, which is a part of the immune system. The complement system is a complex series of biochemical reactions that help to eliminate pathogens and damaged cells from the body.

There are several types of complement activating enzymes, including:

1. Classical pathway activators: These include the C1, C4, and C2 components of the complement system. When activated, they trigger a series of reactions that lead to the formation of the membrane attack complex (MAC), which creates a pore in the membrane of the target cell, leading to its lysis.
2. Alternative pathway activators: These include factors B, D, and P. They are constantly active at low levels and can be activated by surfaces that are not normally found in the body, such as bacterial cell walls. Once activated, they also trigger the formation of the MAC.
3. Lectin pathway activators: These include mannose-binding lectin (MBL) and ficolins. They bind to carbohydrates on the surface of microbes and activate the complement system through the MBL-associated serine proteases (MASPs).

Overall, complement activating enzymes play a critical role in the immune response by helping to identify and eliminate pathogens and damaged cells from the body.

Complement inactivating agents are substances or drugs that inhibit the complement system, which is a part of the immune system responsible for the recognition and elimination of foreign substances and microorganisms. The complement system consists of a group of proteins that work together to help eliminate pathogens from the body.

Complement inactivating agents are used in medical settings to prevent or treat various conditions associated with excessive or unwanted activation of the complement system, such as inflammation, autoimmune diseases, and transplant rejection. These agents can inhibit different components of the complement pathway, including C1 esterase inhibitors, C3 convertase inhibitors, and C5a receptor antagonists.

Examples of complement inactivating agents include eculizumab, ravulizumab, and Alexion's Ultomiris, which are monoclonal antibodies that target C5, a protein involved in the final steps of the complement pathway. These drugs have been approved for the treatment of paroxysmal nocturnal hemoglobinuria (PNH), atypical hemolytic uremic syndrome (aHUS), and other complement-mediated diseases.

Other complement inactivating agents include C1 esterase inhibitors, such as Berinert and Ruconest, which are used to treat hereditary angioedema (HAE). These drugs work by inhibiting the activation of the classical pathway of the complement system, thereby preventing the release of inflammatory mediators that can cause swelling and pain.

Overall, complement inactivating agents play an important role in the treatment of various complement-mediated diseases, helping to reduce inflammation, prevent tissue damage, and improve patient outcomes.

A Complement Hemolytic Activity Assay is a laboratory test used to measure the functionality and activity level of the complement system, which is a part of the immune system. The complement system is a group of proteins that work together to help eliminate pathogens from the body.

The assay measures the ability of the complement system to lyse (break open) red blood cells. This is done by mixing the patient's serum (the liquid portion of the blood) with antibody-coated red blood cells and incubating them together. The complement proteins in the serum will then bind to the antibodies on the red blood cells and cause them to lyse.

The degree of hemolysis (red blood cell lysis) is directly proportional to the activity level of the complement system. By measuring the amount of hemolysis, the assay can determine whether the complement system is functioning properly and at what level of activity.

This test is often used to diagnose or monitor complement-mediated diseases such as autoimmune disorders, infections, and some types of cancer. It may also be used to evaluate the effectiveness of treatments that target the complement system.

Complement C9 is a protein that plays a crucial role in the complement system, which is a part of the immune system that helps to eliminate pathogens and damaged cells from the body. Specifically, C9 is one of the components of the membrane attack complex (MAC), which is a protein structure that forms pores in the membranes of target cells, leading to their lysis or destruction.

When activated, C9 polymerizes and inserts itself into the cell membrane, forming a transmembrane pore that disrupts the membrane's integrity and causes the cell to lyse. This process is an essential part of the complement system's ability to destroy pathogens and clear damaged cells from the body.

Defects in the C9 gene can lead to a rare genetic disorder called complement component 9 deficiency, which is characterized by recurrent bacterial infections and immune complex-mediated diseases. Additionally, mutations in the C9 gene have been associated with an increased risk of age-related macular degeneration (AMD), a leading cause of blindness in older adults.

Complement C3a is a protein fragment that is generated during the activation of the complement system, which is a part of the immune system. The complement system helps to eliminate pathogens and damaged cells from the body by marking them for destruction and attracting immune cells to the site of infection or injury.

C3a is produced when the third component of the complement system (C3) is cleaved into two smaller fragments, C3a and C3b, during the complement activation cascade. C3a is a potent anaphylatoxin, which means it can cause the release of histamine and other mediators from mast cells and basophils, leading to inflammation, increased vascular permeability, and smooth muscle contraction.

C3a also has chemotactic properties, meaning it can attract immune cells such as neutrophils and monocytes to the site of complement activation. Additionally, C3a can modulate the activity of various immune cells, including dendritic cells, T cells, and B cells, and play a role in the regulation of the adaptive immune response.

It's important to note that while C3a has important functions in the immune response, uncontrolled or excessive activation of the complement system can lead to tissue damage and inflammation, contributing to the pathogenesis of various diseases such as autoimmune disorders, inflammatory diseases, and allergies.

Molecular sequence data refers to the specific arrangement of molecules, most commonly nucleotides in DNA or RNA, or amino acids in proteins, that make up a biological macromolecule. This data is generated through laboratory techniques such as sequencing, and provides information about the exact order of the constituent molecules. This data is crucial in various fields of biology, including genetics, evolution, and molecular biology, allowing for comparisons between different organisms, identification of genetic variations, and studies of gene function and regulation.

Complement C3c is a protein component of the complement system, which is a part of the immune system that helps to clear pathogens and damaged cells from the body. Complement C3c is formed when the third component of the complement system (C3) is cleaved into two smaller proteins, C3a and C3b, during the complement activation process.

C3b can then be further cleaved into C3c and C3dg. C3c is a stable fragment that remains in the circulation and can be measured in blood tests as a marker of complement activation. It plays a role in the opsonization of pathogens, which means it coats them to make them more recognizable to immune cells, and helps to initiate the membrane attack complex (MAC), which forms a pore in the cell membrane of pathogens leading to their lysis or destruction.

Abnormal levels of C3c may indicate an underlying inflammatory or immune-mediated condition, such as infection, autoimmune disease, or cancer.

Complement C1 Inactivator proteins are a part of the complement system, which is a group of proteins in the blood that play a crucial role in the body's immune defense system. Specifically, Complement C1 Inactivator proteins are responsible for regulating the activation of the first component of the complement system, C1.

The complement system is activated in response to the presence of foreign substances such as bacteria or viruses in the body. The activation of C1 leads to a cascade of reactions that result in the destruction of the foreign substance. However, if this process is not properly regulated, it can lead to damage to the body's own cells and tissues.

Complement C1 Inactivator proteins help to prevent this by regulating the activation of C1. They do this by binding to and inhibiting the activity of C1, preventing it from initiating the complement cascade. A deficiency in Complement C1 Inactivator proteins can lead to a condition called hereditary angioedema, which is characterized by recurrent episodes of swelling in various parts of the body.

Complement C5a is a protein fragment that is generated during the activation of the complement system, which is a part of the immune system. The complement system helps to eliminate pathogens and damaged cells from the body by tagging them for destruction and attracting immune cells to the site of infection or injury.

C5a is formed when the fifth component of the complement system (C5) is cleaved into two smaller fragments, C5a and C5b, during the complement activation cascade. C5a is a potent pro-inflammatory mediator that can attract and activate various immune cells, such as neutrophils, monocytes, and eosinophils, to the site of infection or injury. It can also increase vascular permeability, promote the release of histamine, and induce the production of reactive oxygen species, all of which contribute to the inflammatory response.

However, excessive or uncontrolled activation of the complement system and generation of C5a can lead to tissue damage and inflammation, contributing to the pathogenesis of various diseases, such as sepsis, acute respiratory distress syndrome (ARDS), and autoimmune disorders. Therefore, targeting C5a or its receptors has been explored as a potential therapeutic strategy for these conditions.

Opsonins are proteins found in the blood that help enhance the immune system's response to foreign substances, such as bacteria and viruses. They do this by coating the surface of these pathogens, making them more recognizable to immune cells like neutrophils and macrophages. This process, known as opsonization, facilitates the phagocytosis (engulfing and destroying) of the pathogen by these immune cells.

There are two main types of opsonins:

1. IgG antibodies: These are a type of antibody produced by the immune system in response to an infection. They bind to specific antigens on the surface of the pathogen, marking them for destruction by phagocytic cells.
2. Complement proteins: The complement system is a group of proteins that work together to help eliminate pathogens. When activated, the complement system can produce various proteins that act as opsonins, including C3b and C4b. These proteins bind to the surface of the pathogen, making it easier for phagocytic cells to recognize and destroy them.

In summary, opsonin proteins are crucial components of the immune system's response to infections, helping to mark foreign substances for destruction by immune cells like neutrophils and macrophages.

Hemolysis is the destruction or breakdown of red blood cells, resulting in the release of hemoglobin into the surrounding fluid (plasma). This process can occur due to various reasons such as chemical agents, infections, autoimmune disorders, mechanical trauma, or genetic abnormalities. Hemolysis may lead to anemia and jaundice, among other complications. It is essential to monitor hemolysis levels in patients undergoing medical treatments that might cause this condition.

Complement C3d is a protein fragment that is formed during the activation of the complement system, which is a part of the immune system. The complement system helps to eliminate pathogens such as bacteria and viruses from the body by tagging them for destruction and attracting immune cells to the site of infection.

C3d is a cleavage product of complement component C3, which is one of the central proteins in the complement system. When C3 is activated, it is cleaved into two fragments: C3a and C3b. C3b can then be further cleaved into C3d and C3c.

C3d plays a role in the activation of the immune system by helping to link the complement system with the adaptive immune response. It does this by binding to receptors on B cells, which are a type of white blood cell that produces antibodies. This interaction can help to stimulate the production of antibodies and enhance the immune response to pathogens.

C3d has also been implicated in the development of certain autoimmune diseases, as it can contribute to the formation of immune complexes that can cause tissue damage.

Blood bactericidal activity refers to the ability of an individual's blood to kill or inhibit the growth of bacteria. This is an important aspect of the body's immune system, as it helps to prevent infection and maintain overall health. The bactericidal activity of blood can be influenced by various factors, including the presence of antibodies, white blood cells (such as neutrophils), and complement proteins.

In medical terms, the term "bactericidal" specifically refers to an agent or substance that is capable of killing bacteria. Therefore, when we talk about blood bactericidal activity, we are referring to the collective ability of various components in the blood to kill or inhibit the growth of bacteria. This is often measured in laboratory tests as a way to assess a person's immune function and their susceptibility to infection.

It's worth noting that not all substances in the blood are bactericidal; some may simply inhibit the growth of bacteria without killing them. These substances are referred to as bacteriostatic. Both bactericidal and bacteriostatic agents play important roles in maintaining the body's defense against infection.

Complement receptor 3b (CR3b or CD11b/CD18) is not a medical definition itself, but I can provide you with the relevant information regarding this term.

Complement receptor 3 (CR3) is a heterodimeric receptor consisting of two subunits, CD11b (also known as Mac-1 or CR3 alpha) and CD18 (also known as beta2 integrin). There are two forms of the CD11b/CD18 heterodimer: CR3a (CD11b/CD18) and CR3b (CD11b/CD18'). The difference between these two forms lies in the conformation of the CD11b subunit.

Complement receptor 3b (CR3b or CD11b/CD18') is a less common form of the CR3 receptor, which is primarily expressed on myeloid cells such as monocytes, macrophages, and neutrophils. CR3b has a higher affinity for complement component C3b and its fragments iC3b and C3dg compared to CR3a.

CR3b plays a role in various immune functions, including:

1. Phagocytosis: Binding of C3b or its fragments to CR3b facilitates the recognition and uptake of opsonized pathogens by phagocytes.
2. Adhesion: The integrin component of CR3b mediates cell-cell and cell-matrix interactions, contributing to leukocyte migration and recruitment to sites of inflammation or infection.
3. Intracellular signaling: Activation of CR3b can lead to intracellular signaling events that modulate immune responses, such as the release of pro-inflammatory cytokines and reactive oxygen species.

In summary, Complement receptor 3b (CR3b or CD11b/CD18') is a less common form of CR3 primarily expressed on myeloid cells that binds complement component C3b and its fragments with high affinity, mediating phagocytosis, adhesion, and intracellular signaling.

Complement fixation tests are a type of laboratory test used in immunology and serology to detect the presence of antibodies in a patient's serum. These tests are based on the principle of complement activation, which is a part of the immune response. The complement system consists of a group of proteins that work together to help eliminate pathogens from the body.

In a complement fixation test, the patient's serum is mixed with a known antigen and complement proteins. If the patient has antibodies against the antigen, they will bind to it and activate the complement system. This results in the consumption or "fixation" of the complement proteins, which are no longer available to participate in a secondary reaction.

A second step involves adding a fresh source of complement proteins and a dye-labeled antibody that recognizes a specific component of the complement system. If complement was fixed during the first step, it will not be available for this secondary reaction, and the dye-labeled antibody will remain unbound. Conversely, if no antibodies were present in the patient's serum, the complement proteins would still be available for the second reaction, leading to the binding of the dye-labeled antibody.

The mixture is then examined under a microscope or using a spectrophotometer to determine whether the dye-labeled antibody has bound. If it has not, this indicates that the patient's serum contains antibodies specific to the antigen used in the test, and a positive result is recorded.

Complement fixation tests have been widely used for the diagnosis of various infectious diseases, such as syphilis, measles, and influenza. However, they have largely been replaced by more modern serological techniques, like enzyme-linked immunosorbent assays (ELISAs) and nucleic acid amplification tests (NAATs), due to their increased sensitivity, specificity, and ease of use.

Complement C1s is a protein that plays a crucial role in the complement system, which is a part of the immune system that helps to clear pathogens and damaged cells from the body. Specifically, C1s is a component of the first protein complex in the classical complement pathway, called C1.

C1 is composed of three subunits: C1q, C1r, and C1s. When C1 encounters an activating surface, such as an antibody-antigen complex or certain types of viruses and bacteria, it undergoes a conformational change that allows C1r to cleave and activate C1s. Activated C1s then goes on to cleave and activate other components in the complement pathway, leading to the generation of the membrane attack complex (MAC) and subsequent lysis of the target cell.

Deficiencies or mutations in the genes encoding complement proteins, including C1s, can lead to various immune disorders and increased susceptibility to infections.

Complement Factor I is a protein involved in the regulation of the complement system, which is a part of the immune system that helps to clear pathogens and damaged cells from the body. Specifically, Complement Factor I is a serine protease that regulates the complement component C3b by cleaving it into inactive fragments, thereby preventing the excessive activation of the complement system and protecting host tissues from damage.

Complement Factor I functions in conjunction with other regulatory proteins, such as complement receptor 1 (CR1) and membrane cofactor protein (MCP), to control the activity of the complement system at various stages. Deficiencies or mutations in Complement Factor I have been associated with several diseases, including atypical hemolytic uremic syndrome (aHUS), age-related macular degeneration (AMD), and systemic lupus erythematosus (SLE).

Complement C4b-binding protein (C4bp) is a regulatory protein in the complement system, which is a part of the immune system that helps to clear pathogens and damaged cells from the body. C4bp regulates the complement system by binding to and inhibiting the activity of C4b, an activated component of the classical and lectin pathways of the complement system. By doing so, C4bp helps to prevent excessive or inappropriate activation of the complement system, which could otherwise lead to tissue damage and inflammation.

C4bp is a complex protein that consists of several subunits, including a central α-chain and multiple β-chains. It is produced by liver cells and can also be found on the surface of some cells in the body. Mutations in the genes encoding C4bp have been associated with certain immune disorders, such as systemic lupus erythematosus (SLE) and atypical hemolytic uremic syndrome (aHUS).

Zymosan is a type of substance that is derived from the cell walls of yeast and some types of fungi. It's often used in laboratory research as an agent to stimulate inflammation, because it can activate certain immune cells (such as neutrophils) and cause them to release pro-inflammatory chemicals.

In medical terms, Zymosan is sometimes used as a tool for studying the immune system and inflammation in experimental settings. It's important to note that Zymosan itself is not a medical condition or disease, but rather a research reagent with potential applications in understanding human health and disease.

I'm sorry for any confusion, but "Mannosephosphates" is not a widely recognized or established term in medicine or biochemistry. It seems that this term may be a combination of "mannose," which is a type of sugar (monosaccharide), and "phosphates," which are compounds containing phosphorus. However, without more context, it's difficult to provide an accurate medical definition for this term.

In biochemistry, mannose can be linked to phosphate groups in various ways, such as in the context of mannose-1-phosphate or mannose-6-phosphate, which are involved in different metabolic pathways. If you could provide more information about where you encountered this term, I might be able to give a more precise definition or explanation.

IGF-2 (Insulin-like Growth Factor 2) receptor is a type of transmembrane protein that plays a role in cell growth, differentiation, and survival. Unlike other receptors in the insulin and IGF family, IGF-2 receptor does not mediate the activation of intracellular signaling pathways upon binding to its ligand (IGF-2). Instead, it acts as a clearance receptor that facilitates the removal of IGF-2 from circulation by transporting it to lysosomes for degradation.

The IGF-2 receptor is also known as cation-independent mannose-6-phosphate receptor (CI-M6PR) because it can also bind and transport mannose-6-phosphate-containing enzymes to lysosomes for degradation.

Mutations in the IGF-2 receptor gene have been associated with certain types of cancer, as well as developmental disorders such as Beckwith-Wiedemann syndrome.

Phagocytosis is the process by which certain cells in the body, known as phagocytes, engulf and destroy foreign particles, bacteria, or dead cells. This mechanism plays a crucial role in the immune system's response to infection and inflammation. Phagocytes, such as neutrophils, monocytes, and macrophages, have receptors on their surface that recognize and bind to specific molecules (known as antigens) on the target particles or microorganisms.

Once attached, the phagocyte extends pseudopodia (cell extensions) around the particle, forming a vesicle called a phagosome that completely encloses it. The phagosome then fuses with a lysosome, an intracellular organelle containing digestive enzymes and other chemicals. This fusion results in the formation of a phagolysosome, where the engulfed particle is broken down by the action of these enzymes, neutralizing its harmful effects and allowing for the removal of cellular debris or pathogens.

Phagocytosis not only serves as a crucial defense mechanism against infections but also contributes to tissue homeostasis by removing dead cells and debris.

Complement C4a is a protein fragment or cleavage product generated during the activation of the complement system, which is a part of the immune system. The complement system helps to eliminate pathogens and damaged cells by marking them for destruction and direct lysis. Complement component 4 (C4) is one of the key proteins in this cascade, and it gets cleaved into C4a and C4b during the activation process.

C4a is a small anaphylatoxin with a molecular weight of approximately 9 kDa. It has chemotactic properties, meaning it can attract immune cells like neutrophils to the site of complement activation. Additionally, C4a can induce histamine release from mast cells and basophils, contributing to local inflammation. However, its precise physiological role in the immune response is not entirely clear, and dysregulation of C4a production has been implicated in several pathological conditions, such as autoimmune diseases and allergies.

Complement C5b is a protein complex that forms during the activation of the complement system, which is a part of the immune system. The complement system helps to eliminate pathogens and damaged cells from the body by marking them for destruction and attracting immune cells to the site of infection or injury.

The complement component C5 is cleaved into two fragments, C5a and C5b, during the activation of the complement system. C5a is a small peptide that acts as a chemoattractant, drawing immune cells to the site of inflammation. C5b, on the other hand, forms a complex with other complement components (C6, C7, C8, and C9) to create the membrane attack complex (MAC). The MAC inserts itself into the membrane of the target cell, forming a pore that disrupts the cell's integrity and leads to its lysis or destruction.

Therefore, Complement C5b is an important protein involved in the immune response, specifically in the terminal phase of complement activation, which results in the formation of the MAC and subsequent destruction of target cells.

Complement C3 Convertase, Alternative Pathway is a complex enzyme composed of the proteins C3b and Bb. It plays a crucial role in the alternative pathway of the complement system, which is a part of the innate immune system that helps to defend the body against invading pathogens.

The alternative pathway is continuously activated at a low level, and C3 Convertase is responsible for amplifying this activation. It does so by cleaving the complement component C3 into C3a and C3b. The C3b then binds to the surface of the pathogen and can form additional C3 Convertases, leading to a positive feedback loop that results in the rapid accumulation of complement components on the surface of the pathogen.

This accumulation of complement components helps to mark the pathogen for destruction by other immune cells, such as neutrophils and macrophages. Additionally, the cleavage products C3a and C5a generated during this process can act as anaphylatoxins, inducing inflammation and attracting more immune cells to the site of infection.

Regulation of Complement C3 Convertase is critical to prevent damage to host tissues. Several regulatory proteins, such as factor H and decay-accelerating factor (DAF), help to limit the formation and activity of C3 Convertase on host cells and tissues. Dysregulation of the complement system, including the alternative pathway and Complement C3 Convertase, has been implicated in a variety of diseases, including autoimmune disorders, inflammatory diseases, and infectious diseases.

The lectin pathway of complement is activated by mannose-binding lectin (MBL) which binds to N-acetylglucosamine. N- ... "Involvement of lectin pathway activation in the complement killing of Giardia intestinalis". Biochemical and Biophysical ... The classical pathway of complement is activated by antibodies specific against Giardia.[citation needed] Antibodies inhibit ... parasite replication and also induce parasite death via the classical pathway of complement.[citation needed] Infection with ...
"The emerging roles of mannose-binding lectin-associated serine proteases (MASPs) in the lectin pathway of complement and beyond ... Mannose-binding protein-associated serine protease are serine proteases involved in the complement system. Types include: MASP1 ... "Molecular characterization of a novel serine protease involved in activation of the complement system by mannose-binding ... MASP2 mannan-binding lectin Dobó, József; Pál, Gábor; Cervenak, László; Gál, Péter (November 2016). " ...
CLR proteins that bind to peptidoglycan include MBL (mannose binding lectin), ficolins, Reg3A (regeneration gene family protein ... In mammals, they initiate the lectin-pathway of the complement cascade. The role of TLRs in direct recognition of peptidoglycan ... They can also bind to LPS and other molecules by using binding sites outside of the peptidoglycan-binding groove. After ... C-type lectins are a diverse superfamily of mainly Ca2+-dependent proteins that bind a variety of carbohydrates (including the ...
The lectin pathway starts with mannose-binding lectin (MBL) or ficolin binding to certain sugars. In this pathway, mannose- ... Classical complement pathway Alternative complement pathway Mannan-binding lectin Wallis R, Mitchell DA, Schmid R, Schwaeble WJ ... The lectin pathway or lectin complement pathway is a type of cascade reaction in the complement system, similar in structure to ... In contrast to the classical complement pathway, the lectin pathway does not recognize an antibody bound to its target. ...
The lectin pathway is homologous to the classical pathway, but with the opsonin, mannose-binding lectin (MBL), and ficolins, ... the classical complement pathway, the alternative complement pathway, and the lectin pathway. The alternative pathway accounts ... The mannose-binding lectin pathway can be activated by C3 hydrolysis or antigens without the presence of antibodies (non- ... Alternative Complement Pathway) Inflammation - by attracting macrophages and neutrophils. (Lectin pathway) Most of the proteins ...
Collectins (e.g. mannose-binding lectin and surfactant protein A) bind the altered surface sugars on apoptotic cell and enable ... components of complement pathways (e.g. C1q, C3b) and other molecules found in extracellular space. ... lectins (binding the altered sugars), the receptor tyrosine kinase MER (recognizing GAS-6), LRP1 (interacts with calreticulin ... Besides complement particles C1q and C3b which help to opsonize the apoptotic cells, also thrombospondin, pentraxins (C- ...
... complement pathway, classical MeSH G04.610.255.849 - complement pathway, mannose-binding lectin MeSH G04.610.270.070 - antibody ... binding sites, antibody MeSH G04.610.143.281 - cross reactions MeSH G04.610.143.545 - hemolysis MeSH G04.610.143.612 - ...
The lectin pathway is activated when pattern-recognition receptors, like mannan-binding lectin or ficolins, recognize and bind ... These bound receptors then complex with Mannose-Binding Lectin-Associated Serine Proteases (MASPs), which have proteolytic ... Degn, Søren E.; Thiel, Steffen; Jensenius, Jens C. (2007-01-01). "New perspectives on mannan-binding lectin-mediated complement ... The classical pathway of complement activation is initiated when the C1 complex, made up of C1r and C1s serine proteases, ...
"Selective inhibition of the lectin pathway of complement with phage display selected peptides against mannose-binding lectin- ... Petersen SV, Thiel S, Jensenius JC (August 2001). "The mannan-binding lectin pathway of complement activation: biology and ... MASP-1 is a serine protease that functions as a component of the lectin pathway of complement activation. The complement ... the mannose-binding lectin and the ficolins. This protein is directly involved in complement activation because MASP-1 ...
"Selective inhibition of the lectin pathway of complement with phage display selected peptides against mannose-binding lectin- ... MASP1 (protein) Mannan-binding lectin Mannan-binding lectin pathway (lectin pathway) GRCh38: Ensembl release 89: ... Petersen SV, Thiel S, Jensenius JC (2001). "The mannan-binding lectin pathway of complement activation: biology and disease ... Mannan-binding lectin serine protease 2 also known as mannose-binding protein-associated serine protease 2 (MASP-2) is an ...
... the classical complement pathway, the alternate complement pathway, and the mannose-binding lectin pathway. The classical ... 12 of which are directly involved in the complement pathways. The complement system is involved in the activities of both ... The complement system consists of more than 35 soluble and cell-bound proteins, ... The B cell waits for a helper T cell (TH) to bind to the complex. This binding will activate the TH cell, which then releases ...
The lectin pathway is triggered when mannose-binding lectin (MBL) or ficolin aka specific pattern recognition receptors bind to ... Each of the three pathways ensures that complement will still be functional if one pathway ceases to work or a foreign invader ... consists of three pathways that are activated in distinct ways. The classical pathway is triggered when IgG or IgM is bound to ... This binding results in the activation of a signaling pathway which allows for the transcription factor NF-κB to enter the ...
... hence preventing cleavage of C4 and C2 mannan-binding lectin lectin pathway Degn SE, Hansen AG, Steffensen R, Jacobsen C, ... Mannose-binding lectin-associated protein of 44 kDa (MAp44) is a protein arising from the human MASP1 gene. MASP-1, MASP-3 and ... protein associated with pattern recognition molecules of the complement system and regulating the lectin pathway of complement ... MAp44 has been suggested to act as a competitive inhibitor of lectin pathway activation, by displacing MASP-2 from MBL, ...
... and the lectin pathway. One way the most-recently discovered lectin pathway is activated is through mannose-binding lectin ... Binding of MBL to a micro-organism results in activation of the lectin pathway of the complement system. Another important ... Mannose-binding lectin (MBL), also called mannan-binding lectin or mannan-binding protein (MBP), is a lectin that is ... The complement system can be activated through three pathways: the classical pathway, the alternative pathway, ...
IgM antibodies also bind to PC. Collectin molecules such as mannose-binding lectin (MBL), surfactant protein A (SP-A), and SP-D ... C3b can spontaneously bind to pathogen surfaces through the alternative complement pathway. Furthermore, pentraxins can ... Mannose-binding lectins, or ficolins, along with pentraxins and collectins are able to recognize certain types of carbohydrates ... Complement proteins involved in innate opsonization include C4b, C3b and iC3b. In the alternative pathway of complement ...
"Mannose-binding lectin deficiency". Genetics Home Reference. U.S. National Library of Medicine. v t e (Articles with short ... MBL deficiency is a pathology of the innate immune system involving Mannan-binding lectin pathway components such as MBL2. It ... description, Short description matches Wikidata, Short description is different from Wikidata, Complement deficiency, All stub ...
... in response to binding to CRP or immunoglobulin, and in the lectin pathway it is driven by mannose binding lectin and its ... lectin, and alternative pathways. Cleavage of complement C3 by a free floating convertase, thrombin, plasmin or even a ... Binding β1H to C3b increases C3bINA binding, while factor B binding prevents C3bINA binding and is competitive with β1H binding ... C4 binding protein (C4BP) interferes with the assembly of the membrane-bound C3 convertase of the classical pathway. C4BP is a ...
Both genes encode proteins of the lectin complement pathway, which plays a role in the complement system of innate, or non- ... "Mannose binding lectin (MBL) and HIV". Molecular Immunology. 42 (2): 145-52. doi:10.1016/j.molimm.2004.06.015. PMID 15488604. ... The protein is a type of connectin called a mannan-binding lectin, which plays a role in innate immunity by binding to ... "Mutations in lectin complement pathway genes COLEC11 and MASP1 cause 3MC syndrome". Nature Genetics. 43 (3): 197-203. doi: ...
"Entrez Gene: LMAN1 lectin, mannose-binding, 1". Khoriaty R, Vasievich MP, Ginsburg D (July 2012). "The COPII pathway and ... 1994). "Complement activation upon binding of mannan-binding protein to HIV envelope glycoproteins". AIDS. 7 (10): 1307-13. doi ... 2003). "High mannose glycans and sialic acid on gp120 regulate binding of mannose-binding lectin (MBL) to HIV type 1". AIDS Res ... The protein is a mannose-specific lectin and is a member of a novel family of plant lectin homologs in the secretory pathway of ...
The extracellular domain of the receptors contains a lectin-like complement-binding domain. Recognition by complement receptors ... Mannose and other pathogen-associated sugars, such as fucose, are recognised by the mannose receptor. Eight lectin-like domains ... Non-opsonic receptors include lectin-type receptors, Dectin receptor, or scavenger receptors. Some phagocytic pathways require ... Among these are receptors that recognise the Fc part of bound IgG antibodies, deposited complement or receptors, that recognise ...
... s are linked with activation of lectin pathway of complement activation. At the beginning, there is a binding of ... Nine types of collectins have been defined: MBL = mannan-binding lectin (mannose-binding lectin) SP-A = surfactant protein A SP ... "The mannan-binding lectin-associated serine proteases (MASPs) and MAp19: four components of the lectin pathway activation ... "The mannan-binding lectin-associated serine proteases (MASPs) and MAp19: four components of the lectin pathway activation ...
Lectin: starts when lectins bind to mannose on bacteria Elements of the complement cascade can be found in many non-mammalian ... "Activation of the human complement alternative pathway by Listeria monocytogenes: evidence for direct binding and proteolysis ... The three different complement systems are classical, alternative and lectin. Classical: starts when antibody binds to bacteria ... The complement system is a biochemical cascade of the immune system that helps, or "complements", the ability of antibodies to ...
... and activate the lectin pathway of the complement cascade. Specifically, ficolins bind to acetyl groups present in certain ... they initiate the proteolytic complement cascade, facilitated by the mannose-binding protein-associated serine proteases (MASPs ... "Lectin-complement pathway molecules are decreased in patients with cirrhosis and constitute the risk of bacterial infections". ... that bind to acetyl groups present in the carbohydrates of bacterial surfaces and mediate activation of the lectin pathway of ...
... system Complement system Classical complement pathway Mannan-binding lectin pathway Alternate complement pathway Complement ... TLR1 TLR2 TLR3 TLR4 TLR5 TLR6 TLR7 TLR8 TLR9 TLR10 TLR11 TLR12 TLR13 C-type lectin receptors (CLRs) Group 1 CLRs - Mannose ... C4a C2 Mannan-binding lectin pathway MASP1 / MASP2 Mannan-binding lectin Alternative complement pathway Factor B Factor D ... see complement proteins section) Collectins Mannan-binding lectin (MBL) Surfactant protein A (SP-A) Surfactant protein D (SP-D ...
Examples include the genes coding for the proteins TNFα, mannan-binding lectin, CTLA4, TGFβ, DC-SIGN, PLCE1, and particular ... the C-type lectins called DC-SIGN, mannose receptor and CLEC5A. DC-SIGN, a non-specific receptor for foreign material on ... October 2019). "Carica papaya extract in dengue: a systematic review and meta-analysis". BMC Complement Altern Med (Review). 19 ... through the innate immune system by augmenting the production of a large group of proteins mediated by the JAK-STAT pathway. ...
Lectin mannose binding 2 LNCR3 encoding protein Lung cancer susceptibility 3 LPCAT1: Lysophosphatidylcholine acyltransferase 1 ... Complement C1q tumor necrosis factor-related protein 3 C5orf45: Chromosome 5 open reading frame 45 C5orf47: encoding protein ... encodes G protein-coupled receptor protein signaling pathway YIPF5: Yip1 domain family member 5 YTHDC2: encoding protein YTH ... Purine-rich element-binding protein A PWWP2A: encoding protein PWWP domain containing 2A RANBP3L: encoding protein RAN binding ...
Matsushita M, Fujita T (December 1992). "Activation of the classical complement pathway by mannose-binding protein in ... mannose-binding lectin-associated serine protease-2, p100, mannan-binding lectin-associated serine peptidase 2) is an enzyme. ... and after Arg76 in complement component C4 (-Gly-Leu-Gln-Arg-Ala-Leu-Glu-Ile) This mannan-binding lectin (MBL) recognizes ... "A second serine protease associated with mannan-binding lectin that activates complement". Nature. 386 (6624): 506-10. doi: ...
Once bound to the ligands MBL and Ficolin oligomers recruit MASP1 and MASP2 and initiate the lectin pathway of complement ... Dommett RM, Klein N, Turner MW (September 2006). "Mannose-binding lectin in innate immunity: past, present and future". Tissue ... One very important collectin is mannan-binding lectin (MBL), a major PRR of the innate immune system that binds to a wide range ... It recognizes and binds to repeated mannose units on the surfaces of infectious agents and its activation triggers endocytosis ...
IgM can bind complement component C1 and activate the classical pathway, leading to opsonization of antigens and cytolysis. IgM ... lectin binding, various chromatographic systems, and enzymatic sensitivity (reviewed in). The structure of the oligosaccharides ... and high mannose-differ among the sites.[citation needed] The multimeric structure of IgM is shown schematically in Figure 1. ... This binding depends on the J chain. Two other Fc receptors that bind IgM-Fcα/µ-R and Fcµ-R -- have been detected. Fcα/µ-R, ...
"Association of Mannose-Binding Lectin Gene Polymorphism but Not of Mannose-Binding Serine Protease 2 with Chronic Severe Aortic ... it triggers the activation of multiple pathways that stimulate further pro-inflammatory cytokine secretion. Mannose-binding ... Kaplan, MH; Bolande, R; Rakita, L; Blair, J (1964). "Presence of Bound Immunoglobulins and Complement in the Myocardium in ... This inflammation occurs through direct attachment of complement and Fc receptor-mediated recruitment of neutrophils and ...
We explored the role of complement in immunity to Giardia using mice deficient in mannose-binding lectin (Mbl2) or complement ... Complement Activation by Giardia duodenalis Parasites through the Lectin Pathway Contributes to Mast Cell Responses and ... These data suggest that complement is a key factor in the innate recognition of Giardia and that recruitment of mast cells and ...
The lectin pathway of complement is activated by mannose-binding lectin (MBL) which binds to N-acetylglucosamine. N- ... "Involvement of lectin pathway activation in the complement killing of Giardia intestinalis". Biochemical and Biophysical ... The classical pathway of complement is activated by antibodies specific against Giardia.[citation needed] Antibodies inhibit ... parasite replication and also induce parasite death via the classical pathway of complement.[citation needed] Infection with ...
Rather, it might be more similar to complement-mediated TMA syndromes, which are well known to rheumatologists who care for ... complement-mediated thrombotic microangiopathy. Here, the authors present the theory and evidence for this disease model and ... are standard treatments for DIC but are gravely insufficient for any of the TMA disorders that involve disorders of complement ... and complement components in regions of thrombotic microangiopathy (TMA). This disorder is not typical DIC. ...
Common variable immunodeficiency and the complement system; low mannose-binding lectin levels are associated with ... Increased functional capacity in both classic and alternative complement pathways in patients with common variable ... Others reported a strong inverse correlation between mannose-binding lectin levels and the frequency of lower respiratory tract ... Reduced class-switched memory B cells; hypogammaglobulinemia; reduced binding of C3d-containing immune complexes and EBV-gp350 ...
... the classical pathway, the alternative pathway and the mannose-binding lectin (MBL) pathway (Figure 1). All three pathways ... The third complement activation pathway, the lectin-binding pathway, is homologous to the classical pathway except that it is ... The lectin complement pathway is homologous to the classical pathway, with the exception that it is activated by the binding of ... Orange boxes highlight regulatory complement proteins. MBL: Mannose-binding lectin; MAC: Membrane attack complex; DAF: Decay ...
Three activating pathways comprise the complement cascade (classical, mannose-binding lectin, and alternative), and all ... Inhibition of the classical pathway of the complement cascade prevents early dendritic and synaptic degeneration in glaucoma. ... Neurodegeneration by Activation of the Microglial Complement-Phagosome Pathway. J Neurosci. 2014; 34:8546-56. [PMID: 24948809] ... demonstrated that serum sources of complement are dispensable for inducing complement-mediated attack in PD and CNV, while ...
The anti-viral mechanisms of MBL include activation of the lectin complement pathway and coagulation, requiring serum factors. ... Mannose-binding lectin (MBL), a pattern recognition innate immune molecule, inhibits influenza A virus infection in vitro. MBL ... E, Lectin complement pathway activation activity. C4 deposition on virus was expressed as U/ml. Assays were performed in ... From: Lack of the pattern recognition molecule mannose-binding lectin increases susceptibility to influenza A virus infection ...
MBL is a soluble molecule that can activate the lectin pathway of the complement system; deficiency may thus lead to defects in ... the complement system (summary by Garcia-Laorden et al., 2008). Genetic Heterogeneity of Lectin Complement Activation Pathway ... Mannose-binding lectin (MBL) deficiency, defined as MBL protein level of less than 100 ng/ml, is present in about 5% of people ... Chronic infections, due to MBL deficiency; LECTIN COMPLEMENT ACTIVATION PATHWAY, DEFECT IN, 1; Mannose-binding protein ...
Complement System and Immunology; Allergic Disorders - Learn about from the MSD Manuals - Medical Professional Version. ... Lectin pathway activation is antibody-independent; it occurs when mannose-binding lectin (MBL), a serum protein, binds to ... There are 3 pathways of complement activation (see figure Complement activation pathways Complement activation pathways ): ... Complement activation pathways. The classical, lectin, and alternative pathways converge into a final common pathway when C3 ...
The lectin activation pathway is similar to the classical pathway, but it is triggered by the binding of mannose-binding lectin ... activating complement cascades through the lectin pathway.. Some cytokines also bind mast cells and basophils, inducing them to ... and lectin pathways.. The alternative pathway is initiated by the spontaneous activation of the complement protein C3. The ... Opsonins from the complement cascade include C1q, C3b, and C4b. Additional important opsonins include mannose-binding proteins ...
This pathway is activated by binding mannan-binding lectin to mannose residues on the pathogen surface, which activates the MBL ... Lectin pathway. The lectin pathway is homologous to the classical pathway, but with the opsonin, [mannan-binding lectin (MBL)]? ... the classical complement pathway, the alternate complement pathway, and the [Mannan-binding lectin (MBL)]? pathway.[1] ... This new lectin pathway of complement activation is important not only for the killing of microorganisms through the ...
The classical mannose binding lectin activation pathway leads to the C3 convertase C4b2a. These convertases cleave C3 resulting ... Complement C3 alpha chain; Complement C3; Complement C3 beta chain; Complement C3 precursor; Complement C3b alpha chain; ... Complement C3c alpha chain fragment 2; Complement C3c fragment; Complement C3d fragment; Complement C3f fragment; Complement ... C3g fragment; Complement component 3; Complement component 3 precursor; Complement component C3; Complement factor 3; CPAMD1; ...
Is capable of host defense against pathogens, by activating the classical complement pathway independently of the antibody. ... Human mannose-binding protein carbohydrate recognition domain trimerizes through a triple α-helical coiled-coil.. ... Binds mannose and n-acetylglucosamine in a calcium-dependent manner. ... mannose-binding lectin (protein C) 2, soluble (opsonic defect). *Mannose-binding protein C precursor (MBP-C) ...
Genetic variations in MBL2 that reduce circulating levels and alter functional properties of the mannose binding lectin (MBL) ... MBL directly mediates opsonophagocytosis and acvation of the C-type lectin complement pathway by binding microbial mannose and ... Mannose binding lectin (MBL) is an acute phase reactant that is secreted from the liver and is critical in host defenses ... Bernig T, Taylor JG, Foster CB, Staats B, Yeager M, Chanock SJ: Sequence analysis of the mannose-binding lectin (MBL2) gene ...
The classical pathway of complement and the lectin activation pathway of mannose binding converge at C4. C1, MASP-1 and MASP-2 ... Rat complement factor C4 (formerly known as Gg protein) is composed of α, β and γ chains. ...
Mannose-binding lectin-associated serine protease (MASP)-2 plays essential roles in the activation of the lectin complement ... Complement factor H acts as a critical negative regulator of the alternative complement pathway. The association of circulating ... We found that the levels of a protein called factor H, which regulates the complement system, could be a potential biomarker of ... Circulating complement factor H levels are associated with disease severity and relapse in autoimmune hepatitis. ...
Pathway ELISA is a qualitative/semiquantitative test that detects activation of the complement system alternative pathway ... Mannose binding lectin (MBL), a major component of the lectin pathway, is associated with bacterial, fungal and viral infection ... Mouse Classical Complement Pathway ELISA Assay Kit. Pig Lectin Complement Pathway ELISA Assay Kit. ... The classical pathway is initiated by binding of C1q to antibody complexes, whereas the alternative and lectin pathway are ...
... are important proteins in the lectin pathway of the immune system. Polymorphism of MBL and MASP-2 genes may affect the serum ... Mannose-binding lectin (MBL) and MBL-associated serine proteases 2 (MASP-2) ... Matsushita M, Endo Y, Fujita T. Cutting edge: complement-activating complex of ficolin and mannose-binding lectin-associated ... Mannose-binding lectin (MBL) and MBL-associated serine proteases 2 (MASP-2) are important proteins in the lectin pathway of the ...
Complement system. Mannose-binding lectin (MBL) is a soluble pattern recognition receptor of the collectin group that activates ... that enhances phagocytosis and activates the lectin pathway of complement activation after binding to lipoteichoic acid or Gram ... Mannose-binding lectin and mannose-binding lectin-associated serine protease 2 in susceptibility, severity, and outcome of ... the lectin complement pathway after binding to a microorganism. Structural mutations in exon 1 of the MBL2 gene resulting in ...
... including genes involved in the Mannose Binding Lectin (MBL) Complement pathway of innate immunity. We hypothesize that the ... When auxin enters the cell, it binds to a receptor protein; this receptor then binds to a repressor protein which typically ... althouth several of the same hexon residues that mediate FX binding also mediate FVII binding to hexon. Furthermore, we found ... and then follow up on those specific pathways to clarify the mechanisms underlying DR. If these pathways are conserved, ...
... will prevent downstream activation of only the classical pathway leaving the alternative and mannose-binding lectin pathways ... C1q is the first complement cascade molecule in the classical pathway and binds pathogenic autoantibodies to initiate the ... 17 25 that may focus on and bind to axonal and nodal membranes whilst the Miller Fisher symptoms (MFS) variant is normally ... 12 13 15 22 Inhibition of C5 nevertheless does not get rid of the production of early LY2886721 complement activation products ...
The salivary scavenger and agglutinin binds MBL and regulates the lectin. pathway of complement in solution and on surfaces. ... Furthermore, differential binding was observed also to known endogenous ligands C1q, mannose-binding lectin, and secretory IgA ... Thus, SALSA has a dual complement activation modifying function. It activates the lectin pathway when bound to a surface and ... The salivary scavenger and agglutinin (SALSA) binds MBL and regulates the lectin pathway of complement in solution and on ...
... which can be split into terminal and proximal complement inhibitors. Many novel terminal complement inhibitors are now in ... which can be split into terminal and proximal complement inhibitors. Many novel terminal complement inhibitors are now in ... At the moment there are three strategies of proximal complement inhibition: anti-C3 agents, anti-factor D agents and anti- ... Indeed, we envision a new scenario of therapeutic complement inhibition, where proximal inhibitors (either anti-C3, anti-FD or ...
Complement Pathway, Classical G12.425.255.698 G12.274.698 Complement Pathway, Mannose-Binding Lectin G12.425.255.849 G12.274. ... Complement Activation G12.425.255 G12.274 Complement Pathway, Alternative G12.425.255.695 G12.274.695 ... Complement 3b D23.50.301.264.35.608 D23.50.301.264.35.618 D23.101.100.110.608 D23.101.100.110.618 Receptors, Complement 3d ... Transferrin-Binding Protein A D12.776.543.750.850.249.500 D12.776.543.750.800.249.500 Transferrin-Binding Protein B D12.776. ...
Complement Pathway, Classical G12.425.255.698 G12.274.698 Complement Pathway, Mannose-Binding Lectin G12.425.255.849 G12.274. ... Complement Activation G12.425.255 G12.274 Complement Pathway, Alternative G12.425.255.695 G12.274.695 ... Complement 3b D23.50.301.264.35.608 D23.50.301.264.35.618 D23.101.100.110.608 D23.101.100.110.618 Receptors, Complement 3d ... Transferrin-Binding Protein A D12.776.543.750.850.249.500 D12.776.543.750.800.249.500 Transferrin-Binding Protein B D12.776. ...
Complement Pathway, Classical G12.425.255.698 G12.274.698 Complement Pathway, Mannose-Binding Lectin G12.425.255.849 G12.274. ... Complement Activation G12.425.255 G12.274 Complement Pathway, Alternative G12.425.255.695 G12.274.695 ... Complement 3b D23.50.301.264.35.608 D23.50.301.264.35.618 D23.101.100.110.608 D23.101.100.110.618 Receptors, Complement 3d ... Transferrin-Binding Protein A D12.776.543.750.850.249.500 D12.776.543.750.800.249.500 Transferrin-Binding Protein B D12.776. ...
Complement Pathway, Classical G12.425.255.698 G12.274.698 Complement Pathway, Mannose-Binding Lectin G12.425.255.849 G12.274. ... Complement Activation G12.425.255 G12.274 Complement Pathway, Alternative G12.425.255.695 G12.274.695 ... Complement 3b D23.50.301.264.35.608 D23.50.301.264.35.618 D23.101.100.110.608 D23.101.100.110.618 Receptors, Complement 3d ... Transferrin-Binding Protein A D12.776.543.750.850.249.500 D12.776.543.750.800.249.500 Transferrin-Binding Protein B D12.776. ...
Complement Pathway, Classical G12.425.255.698 G12.274.698 Complement Pathway, Mannose-Binding Lectin G12.425.255.849 G12.274. ... Complement Activation G12.425.255 G12.274 Complement Pathway, Alternative G12.425.255.695 G12.274.695 ... Complement 3b D23.50.301.264.35.608 D23.50.301.264.35.618 D23.101.100.110.608 D23.101.100.110.618 Receptors, Complement 3d ... Transferrin-Binding Protein A D12.776.543.750.850.249.500 D12.776.543.750.800.249.500 Transferrin-Binding Protein B D12.776. ...
  • The complement system consists of more than 35 soluble and cell-bound proteins, 12 of which are directly involved in the complement pathways. (dadamo.com)
  • The complement system consist of a complex family of proteins and receptors which are found in the circulation, in tissues and other body-fluids. (eaglebio.com)
  • Complement activation proceeds in a sequential fashion through the proteolytic cleavage of a series of proteins leading to the generation of activated products that mediate various biological activities through their interaction with specific cellular receptors and other serum proteins. (eaglebio.com)
  • Mannose-binding lectin (MBL) and MBL-associated serine proteases 2 (MASP-2) are important proteins in the lectin pathway of the immune system. (biomedcentral.com)
  • The complement system consists of a number of small proteins found in the blood, normally circulating as inactive zymogens . (wikidoc.org)
  • Over 20 proteins and protein fragments make up the complement system, including serum proteins, serosal proteins, and cell membrane receptors. (wikidoc.org)
  • Here we investigated if a panel of complement proteins and activation products would provide useful biomarkers for severity of AH and aid in predicting 90 days mortality. (umassmed.edu)
  • APPROACH and RESULTS: Plasma samples collected at time of diagnosis from 254 patients with moderate and severe AH recruited from four medical centers and 31 healthy individuals were used to quantify complement proteins by ELISA and Luminex arrays. (umassmed.edu)
  • 10 This distinction is not absolute because genetic defects in complement proteins have been identified in secondary TMA. (jrheum.org)
  • Interferon(s), which include(s) a group of proteins that are produced by virally infected cells, can bind to noninfected cells and produce a generalized antiviral state. (brmi.online)
  • The article mentions, "Complement activation may occur early during SARS-CoV-2 infection by the direct interaction of viral proteins with mannose- binding lectin and ficolin pathway. (acquaintpublications.com)
  • In a cascade of proteolytic cleavage events, MASP-2 activates complement proteins C4 and C2 to form C4b2a (classical C3 convertase), thereby converging the lectin pathway with the classical pathway of complement activation. (escholarship.org)
  • Further, MASP-2 activity is regulated by several factors, including the serine protease inhibitor C1INH and by interaction with other proteins of the lectin complement pathway. (escholarship.org)
  • These genes provide instructions for making proteins that are involved in a series of steps called the lectin complement pathway. (medlineplus.gov)
  • CD59 can be a membrane-bound inhibitor from the terminal pathway that prevents the development and membrane insertion from the Mac pc by binding the terminal go with proteins (C8 and C9) because they unfold. (biotech2012.org)
  • The plasma proteins element H (fH) and C4-binding protein Ozagrel hydrochloride inhibit the choice and traditional go with pathways respectively both in the liquid stage and on cell areas after their connection. (biotech2012.org)
  • Host cells are covered from strike by GW843682X GW843682X the supplement program by plasma and membrane-bound regulatory substances that inactivate supplement proteins. (researchdataservice.com)
  • C3 convertases are deactivated by dissociation mediated by surface area proteins such as for example GW843682X Decay-Accelerating Aspect (DAF) and Supplement Receptor-1 (CR1) in addition to soluble aspect H. These protein bind to C3b and displace Bb [9]. (researchdataservice.com)
  • The complement system consists of a complex network of several plasma proteins that interact with each other and cell surface proteins. (medscape.com)
  • Increased CH 50 , C3, and C4 values may occur in the context of systemic inflammation as complement proteins are synthesized as part of the acute-phase response in connective-tissue diseases including, but not limited to, SLE and rheumatoid arthritis (RA), severe bacterial and viral infections, and other diseases such as cancer, diabetes mellitus, and myocardial infarction. (medscape.com)
  • C3b binds to other complement proteins on the cell membrane to finally form the membrane attach complex (MAC), which ultimately leads to opening pores in the cell membrane and promoting cell lysis. (medscape.com)
  • Most complement system proteins are synthesized in the liver, although monocytes and macrophages are also a minor source. (medscape.com)
  • The complement system is an integral part of the innate immune system but also augments adaptive immune responses. (wjgnet.com)
  • Mannose-binding lectin deficiency is a condition that affects the immune system. (nih.gov)
  • People with this condition have low levels (deficiency) of an immune system protein called mannose-binding lectin in their blood. (nih.gov)
  • The term "complement" was introduced by Paul Ehrlich in the late 1890s, as part of his larger theory of the immune system. (wikidoc.org)
  • Ehrlich therefore named this heat-labile component "complement", because it is something in the blood which "complements" the cells of the immune system. (wikidoc.org)
  • Complement, a critical component of the innate immune system, contributes to uncontrolled inflammatory responses leading to liver injury, but is also involved in hepatic regeneration. (umassmed.edu)
  • The complement pathways are also a part of the defensive measures of the innate immune system. (brmi.online)
  • MASP-2 (mannose/mannan binding lectin (MBL) associated serine protease-2) is a serum protein predominantly synthesized by the liver as a ~75kDa protein and is one of the key molecules of the innate immune system. (escholarship.org)
  • Genetic deficiencies of complement components certainly are a common denominator of infectious and immune system diseases. (cell-signaling-pathways.com)
  • After birth, the lectin complement pathway is involved in the immune system. (medlineplus.gov)
  • Researchers suggest that similar pathways in the immune system can compensate for problems in the lectin complement pathway, which explains why immune system abnormalities are not part of 3MC syndrome. (medlineplus.gov)
  • Classical pathway activation is normally is certainly and antibody-dependent initiated when C1q binds for an immune system complicated. (biotech2012.org)
  • The traditional pathway (CP) is set up mainly once the C1 complicated binds towards the Fc region of certain antibody isotypes in immune system complexes. (researchdataservice.com)
  • If left to propagate, the accumulation of C3b triggers cleavage of C5 to produce C5a and C5b, with the latter inducing the assembly of a membrane attack complex (MAC) that binds to cell surfaces, forming transmembrane channels that cause cytolysis or apoptosis of the target cells. (molvis.org)
  • C3 cleavage may result in formation of the membrane attack complex (MAC), the cytotoxic component of the complement system. (msdmanuals.com)
  • Protein MASP-2 and MAp19 encoded by MASP-2 genes both can bind with MBL, generate MBL-MASP compound, and then activate C4-C9 components in the complement system, generating membrane attack complex and opsonin as well as other inflammatory cytokines promoting the killing of pathogenic microorganisms [ 10 , 11 ]. (biomedcentral.com)
  • C5b initiates the membrane attack pathway , which results in the membrane attack complex (MAC), consisting of C5b, C6 , C7 , C8 , and polymeric C9 . (wikidoc.org)
  • The functions of complement include the attraction of inflammatory cells, opsonization to promote phagocytosis, immune complex clearance and direct microbial killing through the formation of the membrane attack complex (MAC). (abcam.com)
  • The deficiency can be, in nearly all cases, SRT3190 due to SRT3190 homozygosity for C2 genes having deletions in exon 6, leading to complete lack of C2, or in some instances due to additional C2 gene mutations [8,9] The alternative activation pathway, which is usually C3 dependent, is generally intact in C2 deficiency and can trigger formation of the membrane attack complex (MAC) independently of C2 [4]. (cell-signaling-pathways.com)
  • Three activating pathways comprise the complement cascade (classical, mannose-binding lectin, and alternative), and all converge on the proteolytic cleavage of C3 to generate an arsenal of inflammatory mediators, including the opsonin C3b and the anaphylatoxin C3a. (molvis.org)
  • The classical, lectin, and alternative pathways converge into a final common pathway when C3 convertase (C3 con) cleaves C3 into C3a and C3b. (msdmanuals.com)
  • The classical pathway of complement and the lectin activation pathway of mannose binding converge at C4. (creative-biolabs.com)
  • The three pathways, designated classical, lectin and alternative pathway, converge at a central component into a final common pathway. (eaglebio.com)
  • All pathways converge at C3 activation with the next cleavage of C5. (biotech2012.org)
  • Alterations in the alternative pathway, like properdin or ficolin deficiency, increase the susceptibility to infection. (eaglebio.com)
  • Thus, we hypothesized that the endogenous mannose-binding lectin (MBL)/ficolin-associated protein-1 (MAP-1) that inhibits complement activation in vitro also could be an in vivo regulator by attenuating myocardial schema/reperfusion injury and thrombogenesis when used at pharmacological doses in wild-type mice. (regionh.dk)
  • Thus, we hypothesized that the endogenous mannose-binding lectin (MBL)/ficolin-associated protein-1 (MAP-1) that inhibits complement activation in vitro also could be an in vivo regulator by attenuating myocardial schema/reperfusion injury and thrombogenesis when used at pharmacological doses in wild-type mice.METHODS AND RESULTS: In 2 mouse models, MAP-1 preserves cardiac function, decreases infarct size, decreases C3 deposition, inhibits MBL deposition, and prevents thrombogenesis. (regionh.dk)
  • It is mainly bound to multimeric protein complexes, such as MBL , the three ficolins ( M-ficolin , L-ficolin and H-ficolin ) and collectin kidney 1 (CL-K1, alias CL-11). (escholarship.org)
  • We detected rapid binding of mannan-binding lectin, H-ficolin, and L-ficolin to the surface of T. cruzi, and found that serum depleted of these molecules failed to kill parasites. (herts.ac.uk)
  • Mannose-binding lectin (MBL) deficiency, defined as MBL protein level of less than 100 ng/ml, is present in about 5% of people of European descent and in about 10% of sub-Saharan Africans. (nih.gov)
  • deficiency may thus lead to defects in the complement system (summary by Garcia-Laorden et al. (nih.gov)
  • People with mannose-binding lectin deficiency can develop infections of the upper respiratory tract and other body systems. (nih.gov)
  • Infants and young children with mannose-binding lectin deficiency seem to be more susceptible to infections than affected adults, but adults can also develop recurrent infections. (nih.gov)
  • Background Go with C2 deficiency is the most common genetically determined complete complement deficiency and is associated with a number of diseases. (cell-signaling-pathways.com)
  • In this study, we considered C2 replacement as a therapeutic target to explore the feasibility of restoring the complement pathway in cases of C2 deficiency. (cell-signaling-pathways.com)
  • Anaphylatoxins are proteolytic products of the serine proteases of the complement system: C3a, C4a and C5a. (dadamo.com)
  • According to research findings, after the pathogenic microorganism invades the body, mannose-binding lectin (MBL) binds with mannan residues on its surface, and activate MBL-associated serine Proteases (MASPs) and the lectin pathway of the complement system, generating non-specific immune responses [ 8 , 9 ]. (biomedcentral.com)
  • Mannan-binding lectin (MBL) and MBL-associated serine proteases (MASPs) are involved in the initial step of the lectin pathway of complement activation. (abcam.com)
  • Lectin pathway initiation complexes are composed of multimolecular carbohydrate recognition subcomponents and 3 lectin pathway-specific serine proteases. (regionh.dk)
  • Pattern-recognition molecules such as mannose-binding lectin (MBL), collectins, and ficolins-collectively termed lectins-bind to DAMPs on injured host cells, forming activation complexes with MBL-associated serine proteases 1, 2, and 3 (MASP-1, MASP-2, and MASP-3). (biomedcentral.com)
  • It is central to the alternative pathway that leads to the C3 convertase C3bBb. (biossusa.com)
  • The classical mannose binding lectin activation pathway leads to the C3 convertase C4b2a. (biossusa.com)
  • The three pathways all generate homologous variants of the protease C3-convertase . (wikidoc.org)
  • In all three pathways, a C3-convertase cleaves and activates component C3 , creating C3a and C3b and causing a cascade of further cleavage and activation events. (wikidoc.org)
  • C2a remains associated with C4b to form the classical pathway C3 convertase (C4b2a). (abcam.com)
  • The latter binds to the C3 convertase complex to form C4b2a3b, the classical pathway C5 convertase. (abcam.com)
  • Go with component C2 features as an integral regulator in the first activation phase from the traditional pathway and participates in the forming of the traditional pathway C3 convertase C4b2a [4]. (cell-signaling-pathways.com)
  • Particularly, when mannose-binding lectin (MBL) or ficolins in complicated with MBL-associated serine protease (MASP) substances bind to relevant carbohydrate substances, this qualified prospects to activation of MASP-2 which in turn may cleave both C2 and C4 therefore developing the same C3 convertase as with traditional pathway activation [5]. (cell-signaling-pathways.com)
  • T. cruzi infectious stages resist complement-mediated killing by expressing surface receptors, which dissociate or prevent C3 convertase formation. (herts.ac.uk)
  • The choice pathway is turned on by spontaneous hydrolysis of C3 to a cleavage item (C3b analog) that binds element B (fB) resulting in formation of the choice pathway C3 convertase. (biotech2012.org)
  • MBL directly mediates opsonophagocytosis and acvation of the C-type lectin complement pathway by binding microbial mannose and N-acetylglucosamine surface residues. (biomedcentral.com)
  • The lectin-mediated pathway is normally turned on by mannose-binding lectin getting together with mannose residues on microbial areas. (researchdataservice.com)
  • The complement system is activated via 3 different mechanisms: (1) the classical pathway, which is activated by antibody-antigen complexes, (2) the alternative pathway, which is activated by microbial cell surfaces in the absence of antibodies, and (3) the lectin pathway, which is activated by mannose residues on microbes. (medscape.com)
  • Deficiencies of go with the different parts of the traditional activation pathway, C1, C4 and C2, all result in improved susceptibility to bacterial attacks [2] and improved threat of developing autoimmune disease, especially systemic lupus SRT3190 erythematosus (SLE) [3]. (cell-signaling-pathways.com)
  • The complement system helps clear pathogens from an organism. (dadamo.com)
  • Is capable of host defense against pathogens, by activating the classical complement pathway independently of the antibody. (lu.se)
  • Mannose binding lectin (MBL) is an acute phase reactant that is secreted from the liver and is critical in host defenses against a spectrum of bacterial, fungal, viral, and parasitic pathogens. (biomedcentral.com)
  • The classical pathway is initiated by binding of C1q to antibody complexes, whereas the alternative and lectin pathway are activated in an antibody-independent fashion through the interaction of complement components with respectively specific carbohydrate groups and lipopolysaccharides (LPS) on the surface of foreign pathogens. (eaglebio.com)
  • C3b binds to the surface of pathogens leading to greater internalization by phagocytic cells by opsonization . (wikidoc.org)
  • Kupffer cells and other macrophage cell types help clear complement-coated pathogens. (wikidoc.org)
  • 8 , 11 - 14 Numerous stimuli can drive the activation of the complement system, including apoptotic debris, pathogens, and antibody-antigen complexes, in addition to ischemia-reperfusion injuries associated with organ transplantation. (jrheum.org)
  • 4 , 13 Complement plays a crucial role in host defense against foreign bodies by promoting phagocyte-mediated clearance of cell debris through activation of an inflammatory response, opsonization of pathogens, and lysis of susceptible bacteria and cells. (jrheum.org)
  • Therefore, C2 can be an important element of both the traditional as well as the lectin pathways of go with activation and it is involved in 1st line protection against microbial disease that is needed for recognition and clearance from the invading pathogens [6]. (cell-signaling-pathways.com)
  • It binds to carbohydrates on the surface of mannose-rich pathogens and mediates clearing by phagocytosis or complement activation (Nepomuceno et al. (springeropen.com)
  • The lectin pathway can be triggered when mannose binding protein (MBL) or ficolins bind to conserved carbohydrate constructions. (biotech2012.org)
  • Different fragments, released from individual components during complement activation, operate by a non-cytolytic mechanism through specific receptors present on various cell types. (dadamo.com)
  • From the functional standpoint, complement receptors can be divided into two types: the adherent type and the other receptors. (dadamo.com)
  • Adherent receptors mediate adherence of cells and other particles with bound C3b or C4b fragments and are known as CR1 to CR5. (dadamo.com)
  • The second group of receptors reacts with small complement fragments (C4a, C3a, C5a) as well as with C1q, Ba, Bb and factor H. Stimulation of these receptors results in various biological effects (chemotaxis, secretion of vasoactive amines, mediators of the inflammatory and anaphylactic reaction etc. (dadamo.com)
  • These receptors, which we now call "antibodies", were called by Ehrlich "amboceptors" to emphasize their bifunctional binding capacity: they recognize and bind to a specific antigen, but they also recognize and bind to the heat-labile antimicrobial component of fresh serum. (wikidoc.org)
  • These complexes serve as pathogen receptors, which are further bound to MASP-1 , a serine protease. (escholarship.org)
  • CR1 on erythrocytes may bind circulating immune complexes (that had activated complement) and transport them to the liver where the immune complexes are partially degraded and thus become more soluble. (dadamo.com)
  • Binding of these complexes to their appropriate pathogenic ligands auto-activates MASP-1. (escholarship.org)
  • The immune complexes are deposited throughout the body, potentially causing localized inflammatory reactions in joints and kidneys, and ultimately leading to renal disease from chronic activation of the complement system [10]. (cell-signaling-pathways.com)
  • We explored the role of complement in immunity to Giardia using mice deficient in mannose-binding lectin (Mbl2) or complement factor 3a receptor (C3aR). (nih.gov)
  • Activated complement factor 3, specifically, stimulates platelets through C3a receptor signaling and thereby amplifies thrombus formation. (acquaintpublications.com)
  • In addition, we demonstrate that the infectious stage of T. cruzi inhibits the lectin pathway activation and complement killing expressing the complement C2 receptor inhibitor trispanning (CRIT) protein. (herts.ac.uk)
  • Upon the occupancy of ACE2 by SARS-CoV-2, the increased serum level of free Angiotensin II (Ang II) due to a reduction of ACE2-mediated degradation promotes activation of the NF-kappa B pathway via Ang II type 1 receptor (AT1R), followed by interleukin-6 (IL-6) production. (kegg.jp)
  • Clinical and experimental proof suggests the pathogenic systems in GBS consist of supplement fixation by these autoantibodies resulting in traditional pathway activation. (liveconscience.com)
  • C1q is the first complement cascade molecule in the classical pathway and binds pathogenic autoantibodies to initiate the cascade. (liveconscience.com)
  • These two latter pathogenic mechanisms are the target of novel strategies of anti-complement treatments, which can be split into terminal and proximal complement inhibitors. (frontiersin.org)
  • Dysregulation of the complement cascade contributes to a variety of retinal dystrophies, including age-related macular degeneration (AMD). (molvis.org)
  • The activation of an immune cascade known as the complement system is a crucial factor in the etiology of age-related macular degeneration (AMD). (molvis.org)
  • The current dogma of CFH function is to downregulate the complement cascade, by inhibiting cleavage of C3, limiting the generation of byproducts that spur inflammation. (molvis.org)
  • The complement system is an enzyme cascade that helps defend against infection. (msdmanuals.com)
  • C3 is a central factor in the complement cascade. (biossusa.com)
  • Activation of the complement cascade, with the formation of the effector MAC unit, results in cytotoxic and cytolytic reactions. (dadamo.com)
  • The main functions of the complement cascade and its role in the acute inflammatory reaction are summarized in Table 1. (dadamo.com)
  • The ELISA contains a positive control which can be used as control to ensure that the alternative complement cascade has run completely. (eaglebio.com)
  • In this report we specifically examine the role of the classical complement cascade by using a mouse monoclonal antibody that inhibits the function of C1q. (liveconscience.com)
  • C1 is the first molecule in the classical complement cascade and comprises C1q and two molecules of C1r and C1s respectively. (abcam.com)
  • Activation of the lectin pathway may also trigger the coagulation cascade via MASP-2 cleavage of prothrombin to thrombin. (biomedcentral.com)
  • Together, activation of complement and the coagulation cascade lead to a procoagulant state that may result in development of HSCT-TMA. (biomedcentral.com)
  • The classical pathway is triggered by activation of the C1-complex (which consists of one molecule C1q and two molecules C1r and C1s), either by C1q's binding to antibodies from classes M and G, complexed with antigens , or by its binding C1q to the surface of the pathogen. (wikidoc.org)
  • Alternate pathway activation occurs when components of microbial cell surfaces (eg, yeast walls, bacterial cell wall lipopolysaccharide [endotoxin]) or immunoglobulin (eg, nephritic factor, aggregated IgA) cleave small amounts of C3. (msdmanuals.com)
  • Markers of complement activation were also differentially evident, with C5a increased and the soluble terminal complement complex (sC5b9) decreased in AH. (umassmed.edu)
  • C3 (H2O) binds soluble aspect B (fB). (researchdataservice.com)
  • Bound fB is normally GW843682X cleaved by serine protease aspect D into soluble Ba peptide and the bigger Bb fragment. (researchdataservice.com)
  • Taking into consideration a previous research demonstrating a significant part for the traditional pathway to advertise SCI chances are that the choice pathway plays a crucial part in amplifying traditional pathway initiated go with activation. (biotech2012.org)
  • Newer studies show that C1q insufficiency and C1-inhibitor are protecting in types of SCI 9 11 indicating a significant part for the traditional pathway. (biotech2012.org)
  • Genetic variations in MBL2 that reduce circulating levels and alter functional properties of the mannose binding lectin (MBL) have been associated with many autoimmune and infectious diseases. (biomedcentral.com)
  • After residual ethanol evaporated, the gene for tumor necrosis factor superfamily, member 2 tissues were digested overnight at 56°C in 200 L Buffer (offi cial symbol TNF ) and the mannose-binding lectin gene PKD with 20 L proteinase K (QIAGEN, Valencia, CA, (offi cial symbol MBL2 ). (cdc.gov)
  • Mannose binding lectin gene 2 ( MBL2 ) polymorphisms are reported to be associated with various diseases. (springeropen.com)
  • Out of these, 4 SNPs from 3′ UTR were found to play role in miRNA binding, 7 SNPs from 5′ near and intronic region were predicted to involve in transcription factor binding and expression of MBL2 gene. (springeropen.com)
  • The system consist of three defined pathways which are activated by a pathway specific panel of molecules. (eaglebio.com)
  • The role of complement dysregulation on vascular endothelial cells has been well established in atypical hemolytic uremic syndrome (aHUS), a thrombotic microangiopathy (TMA) characterized by microangiopathic hemolytic anemia, thrombocytopenia, and target organ injury. (jrheum.org)
  • 7 - 9 A TMA is called "primary" when a genetic or acquired defect in a complement protein is identified (as in atypical hemolytic uremic syndrome [aHUS]) or "secondary" when occurring in the context of another disease process or factor such as infection, autoimmune disease, malignancy, or drugs. (jrheum.org)
  • This is a case of saddle pulmonary embolism in a healthy 20 years old COVID-19 patient who had significant elevation of 50 % complement hemolytic Assay with negative COVID-19 testing by PCR and positive SARS-CoV-2 antibody. (acquaintpublications.com)
  • Based on an article by Maurizio Costabile, the classical complement activation is measured by the 50 % complement hemolytic assay ( CH 50) which tests the functional capacity of serum complement components of the classical pathway to lyse sheep red blood cells pre- coated with rabbit anti-sheep red blood cell antibody [3] . (acquaintpublications.com)
  • It has been previously proposed that purified human C2 could restore classical and lectin complement pathways and hemolytic activity ex-vivo in serum collected from C2-deficient patients [11]. (cell-signaling-pathways.com)
  • The reference ranges for total complement (total hemolytic complement: CH 50 [CH 100 ]), complement C3, and complement C4 are listed below. (medscape.com)
  • CH 50 (total hemolytic complement assay) measures the ability of the serum test sample to lyse 50% of sheep RBCs coated with rabbit immunoglobulin, reflecting the functional status of the classical and terminal complement pathways. (medscape.com)
  • This cleavage activates the terminal complement pathway leading to eventually the formation of the terminal C5b-9 complement complex (TCC). (eaglebio.com)
  • Following these cleavage events, complement pathway activation continues as in the classical pathway. (abcam.com)
  • Furthermore, lectin pathway activation by T. cruzi required the MBL-associated serine protease 2 (MASP2) activity resulting in C2 factor cleavage. (herts.ac.uk)
  • Ozagrel hydrochloride In this procedure the anaphylatoxins C3a and C5a are produced and C5 cleavage initiates the terminal go with pathway that culminates in the forming of the membrane assault complex (Mac pc). (biotech2012.org)
  • Specifically the axonal variant of GBS (severe electric motor axonal neuropathy AMAN) is normally strongly connected with circulating anti-GM1 and GD1a ganglioside antibodies [17 25 that may focus on and bind to axonal and nodal membranes whilst the Miller Fisher symptoms (MFS) variant is normally connected with circulating anti-GQ1b ganglioside antibodies with distinctive tissues specificity for cranial nerves [3]. (liveconscience.com)
  • In the early 20th century, this controversy was resolved when it was understood that complement can act in combination with specific antibodies, or on its own in a non-specific way. (wikidoc.org)
  • The classical complement pathway typically requires antibodies for activation (specific immune response), while the alternative and mannose-binding lectin pathways can be activated by C3 hydrolysis or antigens without the presence of antibodies (non-specific immune response). (wikidoc.org)
  • the classical pathway initiated by antibodies bound to the surface of foreign bodies and the alternative and lectin pathways that provide an antibody-independent mechanism for complement activation, induced by the presence of bacteria and other micro-organisms. (abcam.com)
  • C1q attaches to antibodies bound on the pathogen surface, leading to the activation of C1s. (abcam.com)
  • In addition, the following are also involved: antimicrobial peptides, natural antibodies, the complement system, NK cells, and gamma delta T lymphocytes [ 3 ] . (encyclopedia.pub)
  • Many novel terminal complement inhibitors are now in clinical development: they all target C5 (as eculizumab), potentially paralleling the efficacy and safety profile of eculizumab. (frontiersin.org)
  • Indeed, proximal inhibitors are designed to interfere with early phases of complement activation, eventually preventing C3-mediated extravascular hemolysis in addition to intravascular hemolysis. (frontiersin.org)
  • Indeed, we envision a new scenario of therapeutic complement inhibition, where proximal inhibitors (either anti-C3, anti-FD or anti-FB) may prove effective for the treatment of PNH, either in monotherapy or in combination with anti-C5 agents, eventually leading to drastic improvement of hematological response. (frontiersin.org)
  • Learn about the three pathways lead to complement activation and some of their key inhibitors. (abcam.com)
  • Advancements in the understanding of the etiopathogenesis of aHUS paved the way for the successful development of anticomplement therapies (complement C5 inhibitors), which have revolutionized the treatment of aHUS. (jrheum.org)
  • Several complement inhibitors targeting various complement pathways are in clinical trials for the treatment of HSCT-TMA. (biomedcentral.com)
  • Decay accelerating element (DAF) membrane cofactor protein (MCP) and in rodents Crry are Tetracosactide Acetate membrane-bound inhibitors that function to avoid C3 activation (by any pathway). (biotech2012.org)
  • So CCDS's gene number prediction represents a lower bound on the total number of human protein-coding genes. (wikidoc.org)
  • Here, we present the first evidence that T. cruzi activates the complement lectin pathway. (herts.ac.uk)
  • Pulmonary findings were consistent with significant deposits of terminal complement C5b-9, C4d, and MBL associated serum protease in the microvasculature consistent with sustained systemic activation of complement pathways [7] . (acquaintpublications.com)
  • These data reveal key jobs for the choice and terminal go with pathways in the Ozagrel hydrochloride pathophysiology of SCI. (biotech2012.org)
  • MAP-1 at pharmacological doses represents a novel therapeutic approach for human diseases involving the lectin pathway and its associated MASPs. (regionh.dk)
  • Activation of the classical complement pathway by therapeutic anti-thymocyte globulin preparations rapidly enhances monocyte tissue factor procoagulant activity, according to the article. (acquaintpublications.com)
  • Status of mannose-binding lectin (MBL) and complement system in COVID-19 patients and therapeutic applications of antiviral plant MBLs. (cdc.gov)
  • Here we discuss evidence for the role of lectin pathway activation in endothelial injury-associated complications of HSCT and how targeting complement activity may provide therapeutic benefit for patients with HSCT-TMA. (biomedcentral.com)
  • Biotinylated tracer antibody will bind to the bound samples and control. (eaglebio.com)
  • Streptavidin-peroxidase conjugate will bind to the biotinylated tracer antibody. (eaglebio.com)
  • During classical complement is activation by antigen-antibody complex, CH 50 will be high while complement component deficiencies result in low CH 50. (acquaintpublications.com)
  • Although an ELISA-based method was used, the readout reflects the activity rather than the binding of the transcription factors because the primary antibody provided with this kit is specific for an epitope on the bound and active form of the transcription factor. (syksignaling.com)
  • MBL, a member of the collectins, is an important element in innate immunity and is able to activate the complement activation pathway independent of the classical and alternative pathways. (labmate-online.com)
  • The production of SARS-CoV-2 specific IgM and IgG during approximately the second week of the disease may further activate the complement system via the classical pathway whereas IgA can trigger the MBL pathway per Dr. Marcus Bossman's article [4] . (acquaintpublications.com)
  • Alternative pathway components are often lettered (eg, factor B, factor D) or named (eg, properdin). (msdmanuals.com)
  • The Mouse Alternative Complement Pathway ELISA Assay Kit is a qualitative/ semiquantitative ELISA to be used for the in vitro determination of activation of the alternative pathway of the complement system in serum and plasma samples. (eaglebio.com)
  • The Mouse Alternative Complement Pathway ELISA Assay Kit is for research use only and not to be used for diagnostic procedures. (eaglebio.com)
  • The Mouse Alternative Complement Pathway ELISA Assay Kit measures the alternative pathway activity mediated via LPS. (eaglebio.com)
  • The alternative pathway also acts as an amplification loop of the other pathways. (eaglebio.com)
  • A common way to measure the activity of the classical or alternative pathway is the hemolysis of erythrocytes. (eaglebio.com)
  • The Mouse Alternative Complement Pathway ELISA is a ready-to-use solid-phase enzyme-linked immunosorbent assay based on a sandwich principle with a working time of 3½ hours. (eaglebio.com)
  • Therefore its inhibition will prevent downstream activation of only the classical pathway leaving the alternative and mannose-binding lectin pathways intact to counter bacterial infection [28]. (liveconscience.com)
  • The classical and alternative complement pathways. (wikidoc.org)
  • The alternative pathway of complement activation is in a constant state of low-level activation (known as tickover). (abcam.com)
  • In contrast, components of the alternative pathway, including complement factor Ba (CFBa) and factor D (CFD), were increased. (umassmed.edu)
  • Activation of the complement system occurs through the classical (CP), lectin (LP), or alternative (AP) pathways. (jrheum.org)
  • The complement system is the first line of defence against pathogen infection and can be activated by the classic, alternative and lectin pathways. (herts.ac.uk)
  • In this review we discuss current evidence that complement activation contributes to progression of CKD, how complement could cause renal inflammation and whether complement inhibition would slow progression of renal disease. (wjgnet.com)
  • Human mannose-binding protein carbohydrate recognition domain trimerizes through a triple α-helical coiled-coil. (lu.se)
  • We have recently shown that the lectin pathway-specific carbohydrate recognition subcomponent mannose-binding lectin plays an essential role in the pathophysiology of thrombosis and ischemia/reperfusion injury. (regionh.dk)
  • These data improve our understanding of the impact of C3 inhibition in subretinal inflammation and inform the development of treatments for targeting complement activation in diseases such as AMD. (molvis.org)
  • Anti-complement Treatment for Paroxysmal Nocturnal Hemoglobinuria: Time for Proximal Complement Inhibition? (frontiersin.org)
  • At the moment there are three strategies of proximal complement inhibition: anti-C3 agents, anti-factor D agents and anti-factor B agents. (frontiersin.org)
  • Preliminary data clearly demonstrate that proximal complement inhibition is pharmacologically feasible and apparently safe, and may drastically improve the hematological response to complement inhibition in PNH. (frontiersin.org)
  • CONCLUSIONS: Our results suggest that the natural, endogenous inhibitor MAP-1 effectively inhibits lectin pathway activation in vivo. (regionh.dk)
  • Our findings establish that the complement lectin pathway recognizes T. cruzi and provide molecular insights into how the infectious stage inhibits this activation to resist complement system killing. (herts.ac.uk)
  • Complement deficiencies or other defects in the complement system can easily be screened by running an assay for each pathway in parallel or separately. (eaglebio.com)
  • The complement system is an agent pro-inflammatory host defense mechanism that is part of both the night and adaptive immunity. (acquaintpublications.com)
  • The actions of the complement system affect both innate immunity and acquired immunity. (dadamo.com)
  • The complement system influence the activity of numerous cells, tissues and physiological mechanism of the body. (dadamo.com)
  • The complement system is a potent mechanism for initiating and amplifying inflammation. (dadamo.com)
  • A major component of this response is the complement system. (eaglebio.com)
  • Under certain conditions, the complement system can be unfavorable to the host leading to e.g. autoimmune diseases and infections. (eaglebio.com)
  • The complement system is a heat-labile component of blood that confers bactericidal properties. (abcam.com)
  • The complement system is a tightly regulated, cascading protein network representing a key component linking the innate and humoral immune systems. (jrheum.org)
  • Therefore, a clearer understanding of the role of the complement system in TMA associated with other conditions will help to identify patients who would benefit from these therapies. (jrheum.org)
  • The complement system is a tightly regulated, cascading protein network that performs multiple roles in homeostasis and disease prevention and is a key component of both the innate and the humoral immune systems. (jrheum.org)
  • Per Richard Stienm [1] , on UpToDate, the complement system plays a vital role in instructing the adaptive immune response and removal of damaged cells, tissue regeneration, and angiogenesis. (acquaintpublications.com)
  • According to an article in the American Journal of medicine and critical care by Marcus Bossman, MD at Boston University school of medicine, the complement system is suspected to have a critical role during the development of COVID-19. (acquaintpublications.com)
  • The viral nucleocapsid protein binds to a mannose-binding protein-associated serine protease 2 (MASP-2), a key protease of the MBL pathway leading to overactivation of the complement system and worsening of lung injury. (acquaintpublications.com)
  • Trypanosoma cruzi, the causative agent of Chagas disease, has to evade complement system killing and invade the host cells to progress in infection. (herts.ac.uk)
  • Endothelial injury can trigger activation of the complement system, promoting inflammation and the development of endothelial injury syndromes, ultimately leading to organ damage and failure. (biomedcentral.com)
  • In this article, we review the role of the complement system in HSCT-TMA pathogenesis, with a focus on the lectin pathway. (biomedcentral.com)
  • Endothelial injury triggers activation of the complement system-significantly through the lectin pathway-via altered cell-surface patterns on injured endothelial cells, initiating an inflammatory response [ 7 ]. (biomedcentral.com)
  • Following activation, C3, the central protein of the complement system, is cleaved to form C3b, which is bound to the surface of the microbe where the complement is activated, and C3a, which is systemically released and acts as a chemoattractant for inflammatory cells. (medscape.com)
  • The combined effects of complement activation, dysregulated neutrophilia, endothelial injury, and hypercoagulability appear to be intertwined to drive the severe features of COVID-19. (kegg.jp)
  • In particular, the lectin pathway of complement is activated by damage-associated molecular patterns (DAMPs) on the surface of injured endothelial cells. (biomedcentral.com)
  • Two new ELISA kits for assaying Human Mannose-Binding Lectin (MBL) are now available from Cambridge Bioscience the Human MBL ELISA Mannan Binding Assay and the Human MBL-C4 Activation Complex ELISA. (labmate-online.com)
  • it occurs when mannose-binding lectin (MBL), a serum protein, binds to mannose, fucose, or N -acetylglucosamine groups on bacterial cell walls, yeast walls, or viruses. (msdmanuals.com)
  • A further complicating factor is the cross-talk between complement, neutrophils, and coagulation pathways in the pathophysiology of TMA. (jrheum.org)
  • 10 This review aims to provide an assessment of the nature and extent of complement involvement in the underlying pathophysiology of TMA associated with autoimmune diseases that will help to stratify patients for targeted therapy. (jrheum.org)
  • This process is mediated chiefly by C3-convertases that are assembled from complement constituents such as C2, C4, CFB, and CFD in the presence of noxious stimuli. (molvis.org)
  • 2008). Genetic Heterogeneity of Lectin Complement Activation Pathway Defects See also LCAPD2 (613791), caused by variation in the MASP2 gene (605102) on chromosome 1p36, and LCAPD3 (613860), caused by variation in the FCN3 gene (604973) on chromosome 1p36. (nih.gov)
  • COVID-19: disease pathways and gene expression changes predict methylprednisolone can improve outcome in severe cases. (cdc.gov)
  • The choice pathway has an amplification loop for the classical and lectin pathways also. (biotech2012.org)
  • Transgenic parasites overexpressing CRIT were highly resistant to complement-mediated killing. (herts.ac.uk)
  • Mannose binding lectin (MBL), a major component of the lectin pathway, is associated with bacterial, fungal and viral infection. (eaglebio.com)
  • A study on 5 COVID-19 patients with severe symptoms by Cynthia Magro and colleagues [5] further supports the important role complement activation plays in COVID-19 infection [6] . (acquaintpublications.com)
  • Moreover, in a study using virus-infected C3 -/- mice, by Gralinski and colleagues, complement activation was assessed in SARS-CoV infection with C3 activation products in the lung as early as one day after SARS-CoV infection. (acquaintpublications.com)