PathwaysAlternative pathwayCleavageHeat-labile componentProteinsCascadeFragmentsEffectorPathogensLectin pathwayInnateAntigenInflammationReceptorsConvertaseCytotoxicPeptidesHomologousAnaphylatoxinsMembraneSystemBindMoleculeCleaveProteinUnderstoodEhrlichBiologicalBindsComponentBoundCellsTypesSmallRelease
Pathways9
- There are three pathways of activation, each of which leads to the formation of C3a and C3b, which is involved in antigen opsonization. (wikipedia.org)
- Learn about the three pathways lead to complement activation and some of their key inhibitors. (abcam.com)
- 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)
- 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 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)
- 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)
- The classical and alternative complement pathways. (wikidoc.org)
- There are three types of complement cascade, the classical and alternative pathways and the Mannan-binding lectin pathway. (vetsci.co.uk)
- Activation of the complement pathways. (medscape.com)
Alternative pathway5
- The alternative pathway of complement activation is typically always active at low levels in blood plasma through a process called tick-over, in which C3 spontaneously hydrolyzes into its active form, C3(H2O). (wikipedia.org)
- The alternative pathway of complement activation is in a constant state of low-level activation (known as tickover). (abcam.com)
- In a similar manner to the classical pathway, the alternative pathway works by forming the MAC (membrane attack complex). (vetsci.co.uk)
- However in the alternative pathway the complement cascade does not require that an antibody binds to the antigen. (vetsci.co.uk)
- Depending on the nature of complement activators, the classic pathway, the alternative pathway, or the more recently discovered lectin pathway is activated predominantly to produce C3 convertase. (medscape.com)
Cleavage3
- C3a formation occurs through activation and cleavage of complement component 3 in a reaction catalyzed by C3-convertase. (wikipedia.org)
- Following these cleavage events, complement pathway activation continues as in the classical pathway. (abcam.com)
- Both provide a path to the cleavage of C3 which is a central event in complement activation. (vetsci.co.uk)
Heat-labile component2
- The complement system is a heat-labile component of blood that confers bactericidal properties. (abcam.com)
- 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)
Proteins6
- The complement system consists of a number of small proteins found in the blood, normally circulating as inactive zymogens . (wikidoc.org)
- When stimulated by one of several triggers, proteases in the system cleave specific proteins to release cytokines and initiate an amplifying cascade of further cleavages. (wikidoc.org)
- Over 20 proteins and protein fragments make up the complement system, including serum proteins, serosal proteins, and cell membrane receptors. (wikidoc.org)
- The complement system or complement cascade as it is also known is a complex system of multiple proteins involved in inflammation and immunological response. (vetsci.co.uk)
- The complement system as understood today is a multimolecular system composed of more than 32 proteins and consisting of serum proteins, serosal proteins, and cell membrane receptors that bind to complement fragments. (medscape.com)
- The complement system consists of 7 serum and 9 membrane regulatory proteins, 1 serosal regulatory protein, and 8 cell membrane receptors that bind complement fragments. (medscape.com)
Cascade8
- 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 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 end result of this activation cascade is massive amplification of the response and activation of the cell-killing membrane attack complex . (wikidoc.org)
- The complement system is known as a cascade because of the triggering and amplification of further components of the system. (vetsci.co.uk)
- The whole complement cascade can be triggered in its entirety in a matter of microseconds. (vetsci.co.uk)
- During the activation process the smaller 'a' subcomponent peptides which are formed, mediate many of the other effects caused by the complement cascade, for example acting as chemoattractants. (vetsci.co.uk)
- The complement system functions as an interactive sequence, with one reaction leading to another in the form of a cascade. (medscape.com)
Fragments5
- C1q mediates the classical pathway by activating the C1 complex, which cleaves C4 and C2 into smaller fragments (C4a, C4b, C2a, and C2b). (wikipedia.org)
- These effects may involve either the whole complement, or only individual components or fragments. (dadamo.com)
- 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)
- 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)
- This is mediated through fragments of complement components. (dadamo.com)
Effector1
- C3a is an effector of the complement system with a range of functions including T cell activation and survival, angiogenesis stimulation, chemotaxis, mast cell degranulation, and macrophage activation. (wikipedia.org)
Pathogens2
- The complement system helps clear pathogens from an organism. (dadamo.com)
- Kupffer cells and other macrophage cell types help clear complement-coated pathogens. (wikidoc.org)
Lectin pathway2
- 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)
- C-reactive protein (CRP, not shown) leads to classic pathway activation analogous to lectin pathway activation by MBL and ficolins. (medscape.com)
Innate3
- The complement system is an integral part of the innate immune system but also augments adaptive immune responses. (wjgnet.com)
- The actions of the complement system affect both innate immunity and acquired immunity. (dadamo.com)
- The innate immune system comprises physical, chemical, and biological barriers (e.g., the skin , gastric acid , commensal organisms ) and both cellular (e.g., granulocytes , natural killer cells , mast cells ) and humoral ( complement system ) defense mechanisms . (amboss.com)
Antigen1
- Ehrlich believed that each antigen-specific amboceptor had its own specific complement, while Bordet believed that there is only one type of complement. (wikidoc.org)
Inflammation4
- 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)
- Complement activation occurs in progressive chronic kidney disease and may contribute to the chronic inflammation that is characteristically found in the kidney. (wjgnet.com)
- It is therefore possible that inhibiting complement activation would reduce inflammation, lead to reduced fibrosis and preservation of renal function. (wjgnet.com)
- The complement system is a potent mechanism for initiating and amplifying inflammation. (dadamo.com)
Receptors2
- From the functional standpoint, complement receptors can be divided into two types: the adherent type and the other receptors. (dadamo.com)
- Adherence reaction mediated through the CR receptors on phagocytes lead to stimulation of phagocytosis, activation of metabolism and secretory function and movement of phagocytes into the inflammatory site. (dadamo.com)
Convertase5
- This activation induces a conformational change in the thioester domain of C3(H2O) that allows it to bind to a plasma protein called Factor B. This complex is then cleaved by Factor D, a serine protease, to form C3b(H2O)Bb, or fluid-phase C3-convertase. (wikipedia.org)
- C2a remains associated with C4b to form the classical pathway C3 convertase (C4b2a). (abcam.com)
- C2a in the convertase complex cleaves C3 releasing C3a and C3b. (abcam.com)
- The latter binds to the C3 convertase complex to form C4b2a3b, the classical pathway C5 convertase. (abcam.com)
- In the first phase, a series of specific interactions leads to formation of intrinsic complement proteinase, termed C3 convertase. (medscape.com)
Cytotoxic2
- The result of cytotoxic complement reaction may be beneficial for the body (elimination of the infectious agent or damaged cells) or harmful (damage to autologous normal cells by immunopathological reactions). (dadamo.com)
- Classical cytotoxic immunosuppressants act by inhibiting DNA synthesis. (lookformedical.com)
Peptides1
- Anaphylatoxins are small complement peptides that induce proinflammatory responses in tissues. (wikipedia.org)
Homologous1
- C3a has a regulatory process and a structure homologous to complement component C5a, with which it shares 36% of its sequence identity. (wikipedia.org)
Anaphylatoxins1
- Anaphylatoxins are proteolytic products of the serine proteases of the complement system: C3a, C4a and C5a. (dadamo.com)
Membrane2
- 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)
- 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)
System3
- The complement system influence the activity of numerous cells, tissues and physiological mechanism of the body. (dadamo.com)
- The term "complement" was introduced by Paul Ehrlich in the late 1890s, as part of his larger theory of the immune system. (wikidoc.org)
- The components of the complement system can be found throughout the body in fluids, providing the body with a systemic means of protection. (vetsci.co.uk)
Bind1
- 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)
Molecule1
- 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)
Cleave1
- The binding of MBL to mannose and N-acetyl glucosamine in micro-organisms leads to the activation of MASPs, which subsequently cleave C4 and C2. (abcam.com)
Protein2
- A complement protein attacking an invader. (wikidoc.org)
- The important protein components of complement are number C1 to C9 (they are numbered in their order of discovery however and not their order of action as you will see later). (vetsci.co.uk)
Understood1
- 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)
Ehrlich1
- Ehrlich and Morgan termed this factor complement. (medscape.com)
Biological1
- Antibodies depend on complement for many of their biological activities. (vetsci.co.uk)
Binds1
- The C1qrs complex binds with the C4b and C2b subcomponents, releasing C4a and C2a. (vetsci.co.uk)
Component2
- The complement component C1 has three sub-components, q, r and s. (vetsci.co.uk)
- The bound C3b activates the next complement component C5, which again splits up into the subcomponents C5a and C5b upon activation. (vetsci.co.uk)
Bound2
- The classical pathway of complement activation is initiated when the C1 complex, made up of C1r and C1s serine proteases, recognizes the Fc region of IgM or IgG antibodies bound to a pathogen. (wikipedia.org)
- C1q attaches to antibodies bound on the pathogen surface, leading to the activation of C1s. (abcam.com)
Cells1
- Others may act through activation of T-CELLS or by inhibiting the activation of HELPER CELLS. (lookformedical.com)
Types1
- Binding of factor H to C3b increases its inactivation by factor I. Properdin stabilizes it, preventing its inactivation by factors H and I. The alternate pathway does not result in a truly nonspecific activation of complement because it requires specific types of compounds for activation. (medscape.com)
Small1
- Upon activation certain components may split into sub components, usually the small components are named with an 'a' e.g. (vetsci.co.uk)
Release1
- This results in the release of C2b and C2a. (abcam.com)