The process of accumulation of genetic and epigenetic changes over time in individual cells and the effect of the changes on CELL PROLIFERATION.
A group of genetically identical cells all descended from a single common ancestral cell by mitosis in eukaryotes or by binary fission in prokaryotes. Clone cells also include populations of recombinant DNA molecules all carrying the same inserted sequence. (From King & Stansfield, Dictionary of Genetics, 4th ed)
Differential and non-random reproduction of different genotypes, operating to alter the gene frequencies within a population.
Substances that are recognized by the immune system and induce an immune reaction.
LYMPHOCYTE ACTIVATION by a specific ANTIGEN thus triggering clonal expansion of LYMPHOCYTES already capable of mounting an immune response to the antigen.
Substances elaborated by bacteria that have antigenic activity.
Removal, via CELL DEATH, of immature lymphocytes that interact with antigens during maturation. For T-lymphocytes this occurs in the thymus and ensures that mature T-lymphocytes are self tolerant. B-lymphocytes may also undergo clonal deletion.
Proteins, glycoprotein, or lipoprotein moieties on surfaces of tumor cells that are usually identified by monoclonal antibodies. Many of these are of either embryonic or viral origin.
Antigens on surfaces of cells, including infectious or foreign cells or viruses. They are usually protein-containing groups on cell membranes or walls and may be isolated.
IMMUNOGLOBULINS on the surface of B-LYMPHOCYTES. Their MESSENGER RNA contains an EXON with a membrane spanning sequence, producing immunoglobulins in the form of type I transmembrane proteins as opposed to secreted immunoglobulins (ANTIBODIES) which do not contain the membrane spanning segment.
That region of the immunoglobulin molecule that varies in its amino acid sequence and composition, and comprises the binding site for a specific antigen. It is located at the N-terminus of the Fab fragment of the immunoglobulin. It includes hypervariable regions (COMPLEMENTARITY DETERMINING REGIONS) and framework regions.
Lymphoid cells concerned with humoral immunity. They are short-lived cells resembling bursa-derived lymphocytes of birds in their production of immunoglobulin upon appropriate stimulation.
Molecules on the surface of T-lymphocytes that recognize and combine with antigens. The receptors are non-covalently associated with a complex of several polypeptides collectively called CD3 antigens (ANTIGENS, CD3). Recognition of foreign antigen and the major histocompatibility complex is accomplished by a single heterodimeric antigen-receptor structure, composed of either alpha-beta (RECEPTORS, ANTIGEN, T-CELL, ALPHA-BETA) or gamma-delta (RECEPTORS, ANTIGEN, T-CELL, GAMMA-DELTA) chains.
Substances elaborated by viruses that have antigenic activity.
The largest of polypeptide chains comprising immunoglobulins. They contain 450 to 600 amino acid residues per chain, and have molecular weights of 51-72 kDa.
Genes encoding the different subunits of the IMMUNOGLOBULINS, for example the IMMUNOGLOBULIN LIGHT CHAIN GENES and the IMMUNOGLOBULIN HEAVY CHAIN GENES. The heavy and light immunoglobulin genes are present as gene segments in the germline cells. The completed genes are created when the segments are shuffled and assembled (B-LYMPHOCYTE GENE REARRANGEMENT) during B-LYMPHOCYTE maturation. The gene segments of the human light and heavy chain germline genes are symbolized V (variable), J (joining) and C (constant). The heavy chain germline genes have an additional segment D (diversity).
Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.
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.
Lymphocytes responsible for cell-mediated immunity. Two types have been identified - cytotoxic (T-LYMPHOCYTES, CYTOTOXIC) and helper T-lymphocytes (T-LYMPHOCYTES, HELPER-INDUCER). They are formed when lymphocytes circulate through the THYMUS GLAND and differentiate to thymocytes. When exposed to an antigen, they divide rapidly and produce large numbers of new T cells sensitized to that antigen.
The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.
Cell changes manifested by escape from control mechanisms, increased growth potential, alterations in the cell surface, karyotypic abnormalities, morphological and biochemical deviations from the norm, and other attributes conferring the ability to invade, metastasize, and kill.
Mapping of the KARYOTYPE of a cell.
The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment.
Any part or derivative of any protozoan that elicits immunity; malaria (Plasmodium) and trypanosome antigens are presently the most frequently encountered.
Established cell cultures that have the potential to propagate indefinitely.
Polyomavirus antigens which cause infection and cellular transformation. The large T antigen is necessary for the initiation of viral DNA synthesis, repression of transcription of the early region and is responsible in conjunction with the middle T antigen for the transformation of primary cells. Small T antigen is necessary for the completion of the productive infection cycle.
Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.
Antigens determined by leukocyte loci found on chromosome 6, the major histocompatibility loci in humans. They are polypeptides or glycoproteins found on most nucleated cells and platelets, determine tissue types for transplantation, and are associated with certain diseases.
Progressive restriction of the developmental potential and increasing specialization of function that leads to the formation of specialized cells, tissues, and organs.
In vitro method for producing large amounts of specific DNA or RNA fragments of defined length and sequence from small amounts of short oligonucleotide flanking sequences (primers). The essential steps include thermal denaturation of the double-stranded target molecules, annealing of the primers to their complementary sequences, and extension of the annealed primers by enzymatic synthesis with DNA polymerase. The reaction is efficient, specific, and extremely sensitive. Uses for the reaction include disease diagnosis, detection of difficult-to-isolate pathogens, mutation analysis, genetic testing, DNA sequencing, and analyzing evolutionary relationships.
Substances of fungal origin that have antigenic activity.
Differentiation antigens residing on mammalian leukocytes. CD stands for cluster of differentiation, which refers to groups of monoclonal antibodies that show similar reactivity with certain subpopulations of antigens of a particular lineage or differentiation stage. The subpopulations of antigens are also known by the same CD designation.
The major group of transplantation antigens in the mouse.
Any part or derivative of a helminth that elicits an immune reaction. The most commonly seen helminth antigens are those of the schistosomes.
A glycoprotein that is secreted into the luminal surface of the epithelia in the gastrointestinal tract. It is found in the feces and pancreaticobiliary secretions and is used to monitor the response to colon cancer treatment.
Those proteins recognized by antibodies from serum of animals bearing tumors induced by viruses; these proteins are presumably coded for by the nucleic acids of the same viruses that caused the neoplastic transformation.
Antibodies produced by a single clone of cells.
A subclass of HLA-D antigens that consist of alpha and beta chains. The inheritance of HLA-DR antigens differs from that of the HLA-DQ ANTIGENS and HLA-DP ANTIGENS.
A group of antigens that includes both the major and minor histocompatibility antigens. The former are genetically determined by the major histocompatibility complex. They determine tissue type for transplantation and cause allograft rejections. The latter are systems of allelic alloantigens that can cause weak transplant rejection.
Large, transmembrane, non-covalently linked glycoproteins (alpha and beta). Both chains can be polymorphic although there is more structural variation in the beta chains. The class II antigens in humans are called HLA-D ANTIGENS and are coded by a gene on chromosome 6. In mice, two genes named IA and IE on chromosome 17 code for the H-2 antigens. The antigens are found on B-lymphocytes, macrophages, epidermal cells, and sperm and are thought to mediate the competence of and cellular cooperation in the immune response. The term IA antigens used to refer only to the proteins encoded by the IA genes in the mouse, but is now used as a generic term for any class II histocompatibility antigen.
Nuclear antigen with a role in DNA synthesis, DNA repair, and cell cycle progression. PCNA is required for the coordinated synthesis of both leading and lagging strands at the replication fork during DNA replication. PCNA expression correlates with the proliferation activity of several malignant and non-malignant cell types.
Sites on an antigen that interact with specific antibodies.
A glycoprotein that is a kallikrein-like serine proteinase and an esterase, produced by epithelial cells of both normal and malignant prostate tissue. It is an important marker for the diagnosis of prostate cancer.
Differentiation antigens found on thymocytes and on cytotoxic and suppressor T-lymphocytes. CD8 antigens are members of the immunoglobulin supergene family and are associative recognition elements in MHC (Major Histocompatibility Complex) Class I-restricted interactions.
The lipopolysaccharide-protein somatic antigens, usually from gram-negative bacteria, important in the serological classification of enteric bacilli. The O-specific chains determine the specificity of the O antigens of a given serotype. O antigens are the immunodominant part of the lipopolysaccharide molecule in the intact bacterial cell. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)
A trisaccharide antigen expressed on glycolipids and many cell-surface glycoproteins. In the blood the antigen is found on the surface of NEUTROPHILS; EOSINOPHILS; and MONOCYTES. In addition, CD15 antigen is a stage-specific embryonic antigen.
The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.
Carbohydrate antigens expressed by malignant tissue. They are useful as tumor markers and are measured in the serum by means of a radioimmunoassay employing monoclonal antibodies.
A specific HLA-A surface antigen subtype. Members of this subtype contain alpha chains that are encoded by the HLA-A*02 allele family.
An immunoassay utilizing an antibody labeled with an enzyme marker such as horseradish peroxidase. While either the enzyme or the antibody is bound to an immunosorbent substrate, they both retain their biologic activity; the change in enzyme activity as a result of the enzyme-antibody-antigen reaction is proportional to the concentration of the antigen and can be measured spectrophotometrically or with the naked eye. Many variations of the method have been developed.
Complex of at least five membrane-bound polypeptides in mature T-lymphocytes that are non-covalently associated with one another and with the T-cell receptor (RECEPTORS, ANTIGEN, T-CELL). The CD3 complex includes the gamma, delta, epsilon, zeta, and eta chains (subunits). When antigen binds to the T-cell receptor, the CD3 complex transduces the activating signals to the cytoplasm of the T-cell. The CD3 gamma and delta chains (subunits) are separate from and not related to the gamma/delta chains of the T-cell receptor (RECEPTORS, ANTIGEN, T-CELL, GAMMA-DELTA).
Theoretical representations that simulate the behavior or activity of genetic processes or phenomena. They include the use of mathematical equations, computers, and other electronic equipment.
The major immunoglobulin isotype class in normal human serum. There are several isotype subclasses of IgG, for example, IgG1, IgG2A, and IgG2B.
Serological reactions in which an antiserum against one antigen reacts with a non-identical but closely related antigen.
Sets of cell surface antigens located on BLOOD CELLS. They are usually membrane GLYCOPROTEINS or GLYCOLIPIDS that are antigenically distinguished by their carbohydrate moieties.
The process of cumulative change at the level of DNA; RNA; and PROTEINS, over successive generations.
Those hepatitis B antigens found on the surface of the Dane particle and on the 20 nm spherical and tubular particles. Several subspecificities of the surface antigen are known. These were formerly called the Australia antigen.
Polymorphic class I human histocompatibility (HLA) surface antigens present on almost all nucleated cells. At least 20 antigens have been identified which are encoded by the A locus of multiple alleles on chromosome 6. They serve as targets for T-cell cytolytic responses and are involved with acceptance or rejection of tissue/organ grafts.
Membrane glycoproteins consisting of an alpha subunit and a BETA 2-MICROGLOBULIN beta subunit. In humans, highly polymorphic genes on CHROMOSOME 6 encode the alpha subunits of class I antigens and play an important role in determining the serological specificity of the surface antigen. Class I antigens are found on most nucleated cells and are generally detected by their reactivity with alloantisera. These antigens are recognized during GRAFT REJECTION and restrict cell-mediated lysis of virus-infected cells.
Morphologic alteration of small B LYMPHOCYTES or T LYMPHOCYTES in culture into large blast-like cells able to synthesize DNA and RNA and to divide mitotically. It is induced by INTERLEUKINS; MITOGENS such as PHYTOHEMAGGLUTININS, and by specific ANTIGENS. It may also occur in vivo as in GRAFT REJECTION.
Genotypic differences observed among individuals in a population.
55-kDa antigens found on HELPER-INDUCER T-LYMPHOCYTES and on a variety of other immune cell types. CD4 antigens are members of the immunoglobulin supergene family and are implicated as associative recognition elements in MAJOR HISTOCOMPATIBILITY COMPLEX class II-restricted immune responses. On T-lymphocytes they define the helper/inducer subset. CD4 antigens also serve as INTERLEUKIN-15 receptors and bind to the HIV receptors, binding directly to the HIV ENVELOPE PROTEIN GP120.
The property of antibodies which enables them to react with some ANTIGENIC DETERMINANTS and not with others. Specificity is dependent on chemical composition, physical forces, and molecular structure at the binding site.
Human immune-response or Class II antigens found mainly, but not exclusively, on B-lymphocytes and produced from genes of the HLA-D locus. They are extremely polymorphic families of glycopeptides, each consisting of two chains, alpha and beta. This group of antigens includes the -DR, -DQ and -DP designations, of which HLA-DR is most studied; some of these glycoproteins are associated with certain diseases, possibly of immune etiology.
Molecules on the surface of B- and T-lymphocytes that recognize and combine with specific antigens.
The process of cumulative change over successive generations through which organisms acquire their distinguishing morphological and physiological characteristics.
High-molecular weight glycoproteins uniquely expressed on the surface of LEUKOCYTES and their hemopoietic progenitors. They contain a cytoplasmic protein tyrosine phosphatase activity which plays a role in intracellular signaling from the CELL SURFACE RECEPTORS. The CD45 antigens occur as multiple isoforms that result from alternative mRNA splicing and differential usage of three exons.
Antigens of the virion of the HEPATITIS B VIRUS or the Dane particle, its surface (HEPATITIS B SURFACE ANTIGENS), core (HEPATITIS B CORE ANTIGENS), and other associated antigens, including the HEPATITIS B E ANTIGENS.
The processes triggered by interactions of ANTIBODIES with their ANTIGENS.
Test for tissue antigen using either a direct method, by conjugation of antibody with fluorescent dye (FLUORESCENT ANTIBODY TECHNIQUE, DIRECT) or an indirect method, by formation of antigen-antibody complex which is then labeled with fluorescein-conjugated anti-immunoglobulin antibody (FLUORESCENT ANTIBODY TECHNIQUE, INDIRECT). The tissue is then examined by fluorescence microscopy.
Glycoproteins expressed on cortical thymocytes and on some dendritic cells and B-cells. Their structure is similar to that of MHC Class I and their function has been postulated as similar also. CD1 antigens are highly specific markers for human LANGERHANS CELLS.
Class I human histocompatibility (HLA) surface antigens encoded by more than 30 detectable alleles on locus B of the HLA complex, the most polymorphic of all the HLA specificities. Several of these antigens (e.g., HLA-B27, -B7, -B8) are strongly associated with predisposition to rheumatoid and other autoimmune disorders. Like other class I HLA determinants, they are involved in the cellular immune reactivity of cytolytic T lymphocytes.
The production of ANTIBODIES by proliferating and differentiated B-LYMPHOCYTES under stimulation by ANTIGENS.
Serum that contains antibodies. It is obtained from an animal that has been immunized either by ANTIGEN injection or infection with microorganisms containing the antigen.
Immunoglobulins produced in a response to BACTERIAL ANTIGENS.
The introduction of error due to systematic differences in the characteristics between those selected and those not selected for a given study. In sampling bias, error is the result of failure to ensure that all members of the reference population have a known chance of selection in the sample.
Deliberate stimulation of the host's immune response. ACTIVE IMMUNIZATION involves administration of ANTIGENS or IMMUNOLOGIC ADJUVANTS. PASSIVE IMMUNIZATION involves administration of IMMUNE SERA or LYMPHOCYTES or their extracts (e.g., transfer factor, immune RNA) or transplantation of immunocompetent cell producing tissue (thymus or bone marrow).
Antigens expressed primarily on the membranes of living cells during sequential stages of maturation and differentiation. As immunologic markers they have high organ and tissue specificity and are useful as probes in studies of normal cell development as well as neoplastic transformation.
Criteria and standards used for the determination of the appropriateness of the inclusion of patients with specific conditions in proposed treatment plans and the criteria used for the inclusion of subjects in various clinical trials and other research protocols.
The restriction of a characteristic behavior, anatomical structure or physical system, such as immune response; metabolic response, or gene or gene variant to the members of one species. It refers to that property which differentiates one species from another but it is also used for phylogenetic levels higher or lower than the species.
A melanosome-specific protein that plays a role in the expression, stability, trafficking, and processing of GP100 MELANOMA ANTIGEN, which is critical to the formation of Stage II MELANOSOMES. The protein is used as an antigen marker for MELANOMA cells.
A single, unpaired primary lymphoid organ situated in the MEDIASTINUM, extending superiorly into the neck to the lower edge of the THYROID GLAND and inferiorly to the fourth costal cartilage. It is necessary for normal development of immunologic function early in life. By puberty, it begins to involute and much of the tissue is replaced by fat.
The relationships of groups of organisms as reflected by their genetic makeup.
Technique using an instrument system for making, processing, and displaying one or more measurements on individual cells obtained from a cell suspension. Cells are usually stained with one or more fluorescent dyes specific to cell components of interest, e.g., DNA, and fluorescence of each cell is measured as it rapidly transverses the excitation beam (laser or mercury arc lamp). Fluorescence provides a quantitative measure of various biochemical and biophysical properties of the cell, as well as a basis for cell sorting. Other measurable optical parameters include light absorption and light scattering, the latter being applicable to the measurement of cell size, shape, density, granularity, and stain uptake.
Antigens associated with specific proteins of the human adult T-cell immunodeficiency virus (HIV); also called HTLV-III-associated and lymphadenopathy-associated virus (LAV) antigens.
A costimulatory ligand expressed by ANTIGEN-PRESENTING CELLS that binds to CTLA-4 ANTIGEN with high specificity and to CD28 ANTIGEN with low specificity. The interaction of CD80 with CD28 ANTIGEN provides a costimulatory signal to T-LYMPHOCYTES, while its interaction with CTLA-4 ANTIGEN may play a role in inducing PERIPHERAL TOLERANCE.
A sex-specific cell surface antigen produced by the sex-determining gene of the Y chromosome in mammals. It causes syngeneic grafts from males to females to be rejected and interacts with somatic elements of the embryologic undifferentiated gonad to produce testicular organogenesis.
Endogenous tissue constituents that have the ability to interact with AUTOANTIBODIES and cause an immune response.
T-cell receptors composed of CD3-associated alpha and beta polypeptide chains and expressed primarily in CD4+ or CD8+ T-cells. Unlike immunoglobulins, the alpha-beta T-cell receptors recognize antigens only when presented in association with major histocompatibility (MHC) molecules.
An encapsulated lymphatic organ through which venous blood filters.
Nuclear antigens encoded by VIRAL GENES found in HUMAN HERPESVIRUS 4. At least six nuclear antigens have been identified.
Immunologic techniques based on the use of: (1) enzyme-antibody conjugates; (2) enzyme-antigen conjugates; (3) antienzyme antibody followed by its homologous enzyme; or (4) enzyme-antienzyme complexes. These are used histologically for visualizing or labeling tissue specimens.
Differentiation antigens expressed on B-lymphocytes and B-cell precursors. They are involved in regulation of B-cell proliferation.
Immunoglobulin molecules having a specific amino acid sequence by virtue of which they interact only with the ANTIGEN (or a very similar shape) that induced their synthesis in cells of the lymphoid series (especially PLASMA CELLS).
The discipline studying genetic composition of populations and effects of factors such as GENETIC SELECTION, population size, MUTATION, migration, and GENETIC DRIFT on the frequencies of various GENOTYPES and PHENOTYPES using a variety of GENETIC TECHNIQUES.
Elements of limited time intervals, contributing to particular results or situations.
Variant forms of the same gene, occupying the same locus on homologous CHROMOSOMES, and governing the variants in production of the same gene product.
Antigens stimulating the formation of, or combining with heterophile antibodies. They are cross-reacting antigens found in phylogenetically unrelated species.
A class of immunoglobulin bearing mu chains (IMMUNOGLOBULIN MU-CHAINS). IgM can fix COMPLEMENT. The name comes from its high molecular weight and originally being called a macroglobulin.
The hepatitis B antigen within the core of the Dane particle, the infectious hepatitis virion.
A member of the tumor necrosis factor receptor superfamily with specificity for CD40 LIGAND. It is found on mature B-LYMPHOCYTES and some EPITHELIAL CELLS, lymphoid DENDRITIC CELLS. Evidence suggests that CD40-dependent activation of B-cells is important for generation of memory B-cells within the germinal centers. Mutations of the gene for CD40 antigen result in HYPER-IGM IMMUNODEFICIENCY SYNDROME, TYPE 3. Signaling of the receptor occurs through its association with TNF RECEPTOR-ASSOCIATED FACTORS.
A heterogeneous group of immunocompetent cells that mediate the cellular immune response by processing and presenting antigens to the T-cells. Traditional antigen-presenting cells include MACROPHAGES; DENDRITIC CELLS; LANGERHANS CELLS; and B-LYMPHOCYTES. FOLLICULAR DENDRITIC CELLS are not traditional antigen-presenting cells, but because they hold antigen on their cell surface in the form of IMMUNE COMPLEXES for B-cell recognition they are considered so by some authors.
A group of differentiation surface antigens, among the first to be discovered on thymocytes and T-lymphocytes. Originally identified in the mouse, they are also found in other species including humans, and are expressed on brain neurons and other cells.
Binary classification measures to assess test results. Sensitivity or recall rate is the proportion of true positives. Specificity is the probability of correctly determining the absence of a condition. (From Last, Dictionary of Epidemiology, 2d ed)
Technique involving the diffusion of antigen or antibody through a semisolid medium, usually agar or agarose gel, with the result being a precipitin reaction.
The sum of the weight of all the atoms in a molecule.
A multistage process that includes cloning, physical mapping, subcloning, determination of the DNA SEQUENCE, and information analysis.
Immunized T-lymphocytes which can directly destroy appropriate target cells. These cytotoxic lymphocytes may be generated in vitro in mixed lymphocyte cultures (MLC), in vivo during a graft-versus-host (GVH) reaction, or after immunization with an allograft, tumor cell or virally transformed or chemically modified target cell. The lytic phenomenon is sometimes referred to as cell-mediated lympholysis (CML). These CD8-positive cells are distinct from NATURAL KILLER CELLS and NATURAL KILLER T-CELLS. There are two effector phenotypes: TC1 and TC2.
A critical subpopulation of T-lymphocytes involved in the induction of most immunological functions. The HIV virus has selective tropism for the T4 cell which expresses the CD4 phenotypic marker, a receptor for HIV. In fact, the key element in the profound immunosuppression seen in HIV infection is the depletion of this subset of T-lymphocytes.
The complex formed by the binding of antigen and antibody molecules. The deposition of large antigen-antibody complexes leading to tissue damage causes IMMUNE COMPLEX DISEASES.
A critical subpopulation of regulatory T-lymphocytes involved in MHC Class I-restricted interactions. They include both cytotoxic T-lymphocytes (T-LYMPHOCYTES, CYTOTOXIC) and CD8+ suppressor T-lymphocytes.
Proteins prepared by recombinant DNA technology.
Specialized cells of the hematopoietic system that have branch-like extensions. They are found throughout the lymphatic system, and in non-lymphoid tissues such as SKIN and the epithelia of the intestinal, respiratory, and reproductive tracts. They trap and process ANTIGENS, and present them to T-CELLS, thereby stimulating CELL-MEDIATED IMMUNITY. They are different from the non-hematopoietic FOLLICULAR DENDRITIC CELLS, which have a similar morphology and immune system function, but with respect to humoral immunity (ANTIBODY PRODUCTION).
The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.
An albumin obtained from the white of eggs. It is a member of the serpin superfamily.
A glycolipid, cross-species antigen that induces production of antisheep hemolysin. It is present on the tissue cells of many species but absent in humans. It is found in many infectious agents.
A group of the D-related HLA antigens found to differ from the DR antigens in genetic locus and therefore inheritance. These antigens are polymorphic glycoproteins comprising alpha and beta chains and are found on lymphoid and other cells, often associated with certain diseases.
A species of POLYOMAVIRUS originally isolated from Rhesus monkey kidney tissue. It produces malignancy in human and newborn hamster kidney cell cultures.
Laboratory mice that have been produced from a genetically manipulated EGG or EMBRYO, MAMMALIAN.
The species Oryctolagus cuniculus, in the family Leporidae, order LAGOMORPHA. Rabbits are born in burrows, furless, and with eyes and ears closed. In contrast with HARES, rabbits have 22 chromosome pairs.
Members of the class of compounds composed of AMINO ACIDS joined together by peptide bonds between adjacent amino acids into linear, branched or cyclical structures. OLIGOPEPTIDES are composed of approximately 2-12 amino acids. Polypeptides are composed of approximately 13 or more amino acids. PROTEINS are linear polypeptides that are normally synthesized on RIBOSOMES.
The genetic region which contains the loci of genes which determine the structure of the serologically defined (SD) and lymphocyte-defined (LD) TRANSPLANTATION ANTIGENS, genes which control the structure of the IMMUNE RESPONSE-ASSOCIATED ANTIGENS, HUMAN; the IMMUNE RESPONSE GENES which control the ability of an animal to respond immunologically to antigenic stimuli, and genes which determine the structure and/or level of the first four components of complement.
A costimulatory ligand expressed by ANTIGEN-PRESENTING CELLS that binds to CD28 ANTIGEN with high specificity and to CTLA-4 ANTIGEN with low specificity. The interaction of CD86 with CD28 ANTIGEN provides a stimulatory signal to T-LYMPHOCYTES, while its interaction with CTLA-4 ANTIGEN may play a role in inducing PERIPHERAL TOLERANCE.
Immunoglobulins produced in response to VIRAL ANTIGENS.
Genetically identical individuals developed from brother and sister matings which have been carried out for twenty or more generations, or by parent x offspring matings carried out with certain restrictions. All animals within an inbred strain trace back to a common ancestor in the twentieth generation.
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 species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.
Manifestations of the immune response which are mediated by antigen-sensitized T-lymphocytes via lymphokines or direct cytotoxicity. This takes place in the absence of circulating antibody or where antibody plays a subordinate role.
White blood cells formed in the body's lymphoid tissue. The nucleus is round or ovoid with coarse, irregularly clumped chromatin while the cytoplasm is typically pale blue with azurophilic (if any) granules. Most lymphocytes can be classified as either T or B (with subpopulations of each), or NATURAL KILLER CELLS.
A collection of cloned peptides, or chemically synthesized peptides, frequently consisting of all possible combinations of amino acids making up an n-amino acid peptide.
The major interferon produced by mitogenically or antigenically stimulated LYMPHOCYTES. It is structurally different from TYPE I INTERFERON and its major activity is immunoregulation. It has been implicated in the expression of CLASS II HISTOCOMPATIBILITY ANTIGENS in cells that do not normally produce them, leading to AUTOIMMUNE DISEASES.
An inhibitory T CELL receptor that is closely related to CD28 ANTIGEN. It has specificity for CD80 ANTIGEN and CD86 ANTIGEN and acts as a negative regulator of peripheral T cell function. CTLA-4 antigen is believed to play role in inducing PERIPHERAL TOLERANCE.
A technique that combines protein electrophoresis and double immunodiffusion. In this procedure proteins are first separated by gel electrophoresis (usually agarose), then made visible by immunodiffusion of specific antibodies. A distinct elliptical precipitin arc results for each protein detectable by the antisera.
The specific failure of a normally responsive individual to make an immune response to a known antigen. It results from previous contact with the antigen by an immunologically immature individual (fetus or neonate) or by an adult exposed to extreme high-dose or low-dose antigen, or by exposure to radiation, antimetabolites, antilymphocytic serum, etc.
Proteins found in any species of bacterium.
Immunoglobulins produced in a response to PROTOZOAN ANTIGENS.
The genetic constitution of the individual, comprising the ALLELES present at each GENETIC LOCUS.
A component of the B-cell antigen receptor that is involved in B-cell antigen receptor heavy chain transport to the PLASMA MEMBRANE. It is expressed almost exclusively in B-LYMPHOCYTES and serves as a useful marker for B-cell NEOPLASMS.
Cells artificially created by fusion of activated lymphocytes with neoplastic cells. The resulting hybrid cells are cloned and produce pure MONOCLONAL ANTIBODIES or T-cell products, identical to those produced by the immunologically competent parent cell.
Electrophoresis in which a polyacrylamide gel is used as the diffusion medium.
Glycoprotein members of the immunoglobulin superfamily which participate in T-cell adhesion and activation. They are expressed on most peripheral T-lymphocytes, natural killer cells, and thymocytes, and function as co-receptors or accessory molecules in the T-cell receptor complex.
A melanosome-associated protein that plays a role in the maturation of the MELANOSOME.
Sialylated Lewis blood group carbohydrate antigen found in many adenocarcinomas of the digestive tract, especially pancreatic tumors.
The selection or choice of sexual partner in animals. Often this reproductive preference is based on traits in the potential mate, such as coloration, size, or behavioral boldness. If the chosen ones are genetically different from the rejected ones, then NATURAL SELECTION is occurring.
Sensitive tests to measure certain antigens, antibodies, or viruses, using their ability to agglutinate certain erythrocytes. (From Stedman, 26th ed)
Production of new arrangements of DNA by various mechanisms such as assortment and segregation, CROSSING OVER; GENE CONVERSION; GENETIC TRANSFORMATION; GENETIC CONJUGATION; GENETIC TRANSDUCTION; or mixed infection of viruses.
Diagnostic procedures involving immunoglobulin reactions.
Histochemical localization of immunoreactive substances using labeled antibodies as reagents.
The phenomenon of target cell destruction by immunologically active effector cells. It may be brought about directly by sensitized T-lymphocytes or by lymphoid or myeloid "killer" cells, or it may be mediated by cytotoxic antibody, cytotoxic factor released by lymphoid cells, or complement.
Antibodies that react with self-antigens (AUTOANTIGENS) of the organism that produced them.
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 group of dominantly and independently inherited antigens associated with the ABO blood factors. They are glycolipids present in plasma and secretions that may adhere to the erythrocytes. The phenotype Le(b) is the result of the interaction of the Le gene Le(a) with the genes for the ABO blood groups.
A CELL CYCLE and tumor growth marker which can be readily detected using IMMUNOCYTOCHEMISTRY methods. Ki-67 is a nuclear antigen present only in the nuclei of cycling cells.
Antigens which may directly stimulate B lymphocytes without the cooperation of T lymphocytes.
A procedure consisting of a sequence of algebraic formulas and/or logical steps to calculate or determine a given task.
DNA molecules capable of autonomous replication within a host cell and into which other DNA sequences can be inserted and thus amplified. Many are derived from PLASMIDS; BACTERIOPHAGES; or VIRUSES. They are used for transporting foreign genes into recipient cells. Genetic vectors possess a functional replicator site and contain GENETIC MARKERS to facilitate their selective recognition.
Costimulatory T-LYMPHOCYTE receptors that have specificity for CD80 ANTIGEN and CD86 ANTIGEN. Activation of this receptor results in increased T-cell proliferation, cytokine production and promotion of T-cell survival.
Immunoglobulins produced in a response to HELMINTH ANTIGENS.
A tumor necrosis factor receptor subtype found in a variety of tissues and on activated LYMPHOCYTES. It has specificity for FAS LIGAND and plays a role in regulation of peripheral immune responses and APOPTOSIS. Multiple isoforms of the protein exist due to multiple ALTERNATIVE SPLICING. The activated receptor signals via a conserved death domain that associates with specific TNF RECEPTOR-ASSOCIATED FACTORS in the CYTOPLASM.
Extrachromosomal, usually CIRCULAR DNA molecules that are self-replicating and transferable from one organism to another. They are found in a variety of bacterial, archaeal, fungal, algal, and plant species. They are used in GENETIC ENGINEERING as CLONING VECTORS.
Glycoproteins found on the membrane or surface of cells.
Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.
Glycoproteins expressed on all mature T-cells, thymocytes, and a subset of mature B-cells. Antibodies specific for CD5 can enhance T-cell receptor-mediated T-cell activation. The B-cell-specific molecule CD72 is a natural ligand for CD5. (From Abbas et al., Cellular and Molecular Immunology, 2d ed, p156)
Recombinant proteins produced by the GENETIC TRANSLATION of fused genes formed by the combination of NUCLEIC ACID REGULATORY SEQUENCES of one or more genes with the protein coding sequences of one or more genes.
A closely related group of antigens found in the plasma only during the infective phase of hepatitis B or in virulent chronic hepatitis B, probably indicating active virus replication; there are three subtypes which may exist in a complex with immunoglobulins G.
A technique using antibodies for identifying or quantifying a substance. Usually the substance being studied serves as antigen both in antibody production and in measurement of antibody by the test substance.
Class I human histocompatibility (HLA) antigens encoded by a small cluster of structural genes at the C locus on chromosome 6. They have significantly lower immunogenicity than the HLA-A and -B determinants and are therefore of minor importance in donor/recipient crossmatching. Their primary role is their high-risk association with certain disease manifestations (e.g., spondylarthritis, psoriasis, multiple myeloma).
A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine).
The fluctuation of the ALLELE FREQUENCY from one generation to the next.
Glycoproteins found on immature hematopoietic cells and endothelial cells. They are the only molecules to date whose expression within the blood system is restricted to a small number of progenitor cells in the bone marrow.
An increased reactivity to specific antigens mediated not by antibodies but by cells.
Carbohydrate antigen most commonly seen in tumors of the ovary and occasionally seen in breast, kidney, and gastrointestinal tract tumors and normal tissue. CA 125 is clearly tumor-associated but not tumor-specific.
RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3' end, referred to as the poly(A) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.
Cells grown in vitro from neoplastic tissue. If they can be established as a TUMOR CELL LINE, they can be propagated in cell culture indefinitely.
A measure of the binding strength between antibody and a simple hapten or antigen determinant. It depends on the closeness of stereochemical fit between antibody combining sites and antigen determinants, on the size of the area of contact between them, and on the distribution of charged and hydrophobic groups. It includes the concept of "avidity," which refers to the strength of the antigen-antibody bond after formation of reversible complexes.
Allelic alloantigens often responsible for weak graft rejection in cases when (major) histocompatibility has been established by standard tests. In the mouse they are coded by more than 500 genes at up to 30 minor histocompatibility loci. The most well-known minor histocompatibility antigen in mammals is the H-Y antigen.
Changes in biological features that help an organism cope with its ENVIRONMENT. These changes include physiological (ADAPTATION, PHYSIOLOGICAL), phenotypic and genetic changes.
The proportion of one particular in the total of all ALLELES for one genetic locus in a breeding POPULATION.
Immunologically detectable substances found in the CELL NUCLEUS.
A specific HLA-B surface antigen subtype. Members of this subtype contain alpha chains that are encoded by the HLA-B*27 allele family.
Tumors or cancer of the PROSTATE.
The arrangement of two or more amino acid or base sequences from an organism or organisms in such a way as to align areas of the sequences sharing common properties. The degree of relatedness or homology between the sequences is predicted computationally or statistically based on weights assigned to the elements aligned between the sequences. This in turn can serve as a potential indicator of the genetic relatedness between the organisms.
A major histocompatibily complex class I-like protein that plays a unique role in the presentation of lipid ANTIGENS to NATURAL KILLER T-CELLS.
The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.
Antigens produced by various strains of HEPATITIS D VIRUS.
Computer-based representation of physical systems and phenomena such as chemical processes.
Identification of proteins or peptides that have been electrophoretically separated by blot transferring from the electrophoresis gel to strips of nitrocellulose paper, followed by labeling with antibody probes.
Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.
Deliberate breeding of two different individuals that results in offspring that carry part of the genetic material of each parent. The parent organisms must be genetically compatible and may be from different varieties or closely related species.
Conjugated protein-carbohydrate compounds including mucins, mucoid, and amyloid glycoproteins.
The mating of plants or non-human animals which are closely related genetically.
Local surface sites on antibodies which react with antigen determinant sites on antigens (EPITOPES.) They are formed from parts of the variable regions of FAB FRAGMENTS.
A specific HLA-A surface antigen subtype. Members of this subtype contain alpha chains that are encoded by the HLA-A*01 allele family.
Polysaccharides found in bacteria and in capsules thereof.
The major human blood type system which depends on the presence or absence of two antigens A and B. Type O occurs when neither A nor B is present and AB when both are present. A and B are genetic factors that determine the presence of enzymes for the synthesis of certain glycoproteins mainly in the red cell membrane.
An HLA-DR antigen which is associated with HLA-DRB1 CHAINS encoded by DRB1*04 alleles.
Glycoproteins with a wide distribution on hematopoietic and non-hematopoietic cells and strongly expressed on macrophages. CD58 mediates cell adhesion by binding to CD2; (ANTIGENS, CD2); and this enhances antigen-specific T-cell activation.
The total process by which organisms produce offspring. (Stedman, 25th ed)
Antigens that exist in alternative (allelic) forms in a single species. When an isoantigen is encountered by species members who lack it, an immune response is induced. Typical isoantigens are the BLOOD GROUP ANTIGENS.
Short sequences (generally about 10 base pairs) of DNA that are complementary to sequences of messenger RNA and allow reverse transcriptases to start copying the adjacent sequences of mRNA. Primers are used extensively in genetic and molecular biology techniques.

BAFF and selection of autoreactive B cells. (1/35)

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Unifying concepts of MHC-dependent natural killer cell education. (2/35)

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Regulated release of nitric oxide by nonhematopoietic stroma controls expansion of the activated T cell pool in lymph nodes. (3/35)

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The carboxypeptidase ACE shapes the MHC class I peptide repertoire. (4/35)

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Mucosal memory CD8(+) T cells are selected in the periphery by an MHC class I molecule. (5/35)

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Coreceptor gene imprinting governs thymocyte lineage fate. (6/35)

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Elongation factor-2, a Th1 stimulatory protein of Leishmania donovani, generates strong IFN-gamma and IL-12 response in cured Leishmania-infected patients/hamsters and protects hamsters against Leishmania challenge. (7/35)

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HLA B*5701-positive long-term nonprogressors/elite controllers are not distinguished from progressors by the clonal composition of HIV-specific CD8+ T cells. (8/35)

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Learn more about Chronic Progressive External Ophthalmoplegia from related diseases, pathways, genes and PTMs with the Novus Bioinformatics Tool.
In Tune :: M.I. Hummel #414 :: TMK-6 This set was purchased around 25 years ago. For most of the time Ive had it, its been safely tucked away i
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Here are some very clear clips for the immune responses to infection, starting with a really well done explanation of Burnets Nobel-winning clonal selection theory: If you like that, check out some more of the videos from the Walter and Eliza Hall Institute of Medical Research. Try this animation and quiz: McGraw Hill Online Centre…
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... in support of Burnet's clonal selection theory. In 1968 Ada was appointed head of the Microbiology Department at the John ... From 1962 he focused on immune reactions, demonstrating that antigens are not present in antibody-producing cells, ... during his period of leadership the school became an international centre for the analysis of T cell-mediated immunity. He was ...
... which also rise extrathymically and transfer peripheral antigens from the periphery to the thymus to mediate selection ... They were also shown to be more efficient in T regulatory cells selection than clonal deletion. The last abundant subset of ... acquisition via trogocytosis, how antigen transfer can be mediated. There is also an evidence, that antigen transfer and ... Gallegos AM, Bevan MJ (October 2004). "Central tolerance to tissue-specific antigens mediated by direct and indirect antigen ...
Mimotope Tumor antigen Antigen-antibody interaction Immunogenetics Affinity maturation Somatic hypermutation Clonal selection V ... Antibody-dependent cell-mediated cytotoxicity (ADCC) Foreign Pernicious anemia Hemolytic disease of the newborn Autoimmune ... Tolerance Central tolerance Peripheral tolerance Clonal anergy Clonal deletion Tolerance in pregnancy Immunodeficiency Antigen ... T cells Antigen receptor - T cell receptor (TCR) Subunits - [email protected] / [email protected] / [email protected] / [email protected] Co-receptors CD8 (CD8α / CD8β) CD4 ...
Myriad receptors are produced through a process known as clonal selection. According to the clonal selection theory, at birth, ... "antigen-specific immunity mediated by somatic gene rearrangements that create clone-defining antigen receptors". In the last ... Once activated, the CTL undergoes a process called clonal selection, in which it gains functions and divides rapidly to produce ... Exogenous antigens are usually displayed on MHC class II molecules, which activate CD4+T helper cells. Endogenous antigens are ...
Clonal anergy Clonal deletion Clonal selection Clone (cell biology) CMKLR1 Colony stimulating factor 1 receptor Colony- ... opsonization Antibody-dependent cell-mediated cytotoxicity Antibody-dependent enhancement Antigen Antigen presentation Antigen ... antitumor immunity CD74 CD94/NKG2 Cell-mediated immunity CELSR1 Central tolerance Chemokine Chemokine receptor Chimeric antigen ... Fc receptor Fc receptor-like molecule FcεRI Fibroblast-like synoviocyte FITkit FluoroSpot Forssman antigen Fragment antigen- ...
This high mutation rate makes them prone to the selection of B-cells lacking the CD20 antigen following treatment with CD20- ... A study of DLBCL cell lines indicated that 14-3-3ζ proteins may play a role in mediating resistance of DLBCL cells to CHOP. 14- ... Clonal B-cells spontaneously mutate the idiotypic region of their immunoglobulin. ... B-cells that have not encountered an antigen are called naive B cells. When naïve B-cells encounter an antigen, one of the ...
Hence veto activity is selective but is not T-cell receptor mediated. Both clonal anergy and clonal deletion have been shown to ... This means that T-cells with a T-cell receptor specific to antigens presented on the veto cell, bind to the veto cell, and are ... in the thymus and suppressive cells that eliminate or induce tolerance on autoreactive lymphocytes that escaped selection. Veto ... These are the same T-cells that mediate graft rejection. This means that the addition of donor-veto cells to the donor graft ...
... of the cells are produced that target the same antigen. This is called clonal selection. Both B cells and T cells carry ... These reactions are mediated by T cells, monocytes, and macrophages. Inflammation is one of the first responses of the immune ... antigen without any need for antigen processing. Such antigens may be large molecules found on the surfaces of pathogens, but ... antigens during a process called antigen presentation. Antigen specificity allows for the generation of responses that are ...
This idea is known as clonal selection theory. At the time, many leading scientists including Linus Pauling and James Watson ... Compatibility genes were essential in immune system mediated viral clearing. The pair coined the term "MHC Restriction" to ... The Hu-1 antigens were renamed the Human-lymphoid (HL) allo-antigens (HL-As). Allo-antigen comes from the observation that a ... Human leukocyte antigens (HLA) began as a list of antigens identified as a result of transplant rejection. The antigens were ...
Coutinho A, Forni L, Holmberg D, Ivars F, Vaz N (1984). "From an antigen-centered, clonal perspective of immune responses to an ... In the mid-1950s, Macfarlane Burnet, inspired by a suggestion made by Niels Jerne, formulated the clonal selection theory (CST ... Symbiont-mediated defenses are also heritable across host generations, despite a non-genetic direct basis for the transmission ... An antigen is a substance that ignites the immune response. The cells involved in recognizing the antigen are Lymphocytes. Once ...
Clonal selection[edit]. For more details on lymph nodes, germinal centers of lymph nodes and clonal selection of B cells, see ... Steps in production of antibodies by B cells: 1. Antigen is recognized and engulfed by B cell 2. Antigen is processed 3. ... The role of lymphocytes in mediating both cell-mediated and humoral responses was demonstrated by James Gowans in 1959.[30] ... The clonal selection theory was proved correct when Sir Gustav Nossal showed that each B cell always produces only one antibody ...
It was published that mTECs mediate clonal deletion (recessive tolerance), via presentation of TRAs, which leads to the ... "Selection of Foxp3+ regulatory T cells specific for self antigen expressed and presented by Aire+ medullary thymic epithelial ... namely clonal deletion or T regulatory cells selection, respectively. N.B.: All the below cited references utilized mouse as a ... mediated selection". Proceedings of the National Academy of Sciences of the United States of America. 109 (20): 7847-52. doi: ...
Myriad receptors are produced through a process known as clonal selection.[1][2] According to the clonal selection theory, at ... "antigen-specific immunity mediated by somatic gene rearrangements that create clone-defining antigen receptors". In the last ... Exogenous antigensEdit. Antigen presentation stimulates T cells to become either "cytotoxic" CD8+ cells or "helper" CD4+ cells. ... Antigen presentationEdit. Main article: Antigen presentation. Acquired immunity relies on the capacity of immune cells to ...
... in the theory of clonal selection which holds that a B cell has on its surface immunoglobulin receptors whose antigen binding ... Shamovsky I, Ivannikov M, Kandel ES, Gershon D, Nudler E (March 2006). "RNA-mediated response to heat shock in mammalian cells ... A modification of Jerne's theory of antibody production using the concept of clonal selection. CA: A Cancer Journal for ... an indicator of antigen-induced signal transduction in antigen-binding cells". Journal of Immunology. 122 (4): 1278-84. PMID ...
Burnet FM (1959). The clonal selection theory of acquired immunity. Nashville, Temessee: Vanderbilt University Press. doi: ... The variable domain of the B-cell antigen receptor is encoded by the V, (D), and J gene segments, the recombination of which ... the Igκ locus is generally inactivated by RAG-mediated deletion of the exon Cκ. The V(D)J recombination step is a random and ... This subsequently results in each B lymphocyte being able to recognize only one antigen. This is significant as the co- ...
The thymus and the bone marrow constitute the primary lymphoid organs involved in the production and early clonal selection of ... For example, the follicles expand significantly when encountering a foreign antigen. The selection of B cells, or B lymphocytes ... The reason that these patients tend to live longer is thought to be the immune response against the tumor, which is mediated by ... The peripheral lymphoid organs are the sites of lymphocyte activation by antigens. Activation leads to clonal expansion and ...
Negative selection occurs through the binding of self-antigen with the BCR; If the BCR can bind strongly to self-antigen, then ... Upon antigen binding, the memory B cell takes up the antigen through receptor-mediated endocytosis, degrades it, and presents ... the B cell undergoes one of four fates: clonal deletion, receptor editing, anergy, or ignorance (B cell ignores signal and ... Once a BCR binds a TD antigen, the antigen is taken up into the B cell through receptor-mediated endocytosis, degraded, and ...
... allowing for more clonal selection of the immunodominant T cells over the subdominant T cells. Immunodominant T cells also ... Antigen-presenting cells such as dendritic cells, can have up to six different types of MHC molecules for antigen presentation ... Immunodominance is evident for both antibody-mediated immunity and cell-mediated immunity. Epitopes that are not targeted or ... Antigens from a particular pathogen can be of variable immunogenicity, with the antigen that stimulates the strongest response ...
... is known as clonal anergy. The mechanism of clonal anergy is important to maintain tolerance to many autologous antigens. ... This negative selection is known as clonal deletion, one of the mechanisms for B cell tolerance. Approximately 99 percent of ... Autoreactive T cells are activated de novo by self epitopes released secondary to pathogen-specific T cell-mediated bystander ... Cells that survive positive selection, but bind strongly to self-antigens are negatively selected also by active induction of ...
Negative selection in the medulla then obliterates T cells that bind too strongly to self-antigens expressed on MHC molecules. ... "Disappearance of T Cell-Mediated Rejection Despite Continued Antibody-Mediated Rejection in Late Kidney Transplant Recipients ... Virtual memory T cells differ from the other memory subsets in that they do not originate following a strong clonal expansion ... Antigen-naive T cells expand and differentiate into memory and effector T cells after they encounter their cognate antigen ...
Affinity-based selection of regulatory T cells occurs independent of agonist-mediated induction of Foxp3 expression. „J Immunol ... Selection of Foxp3+ regulatory T cells specific for self antigen expressed and presented by Aire+ medullary thymic epithelial ... B7/CD28 in central tolerance: costimulation promotes maturation of regulatory T cell precursors and prevents their clonal ... Steady state migratory RelB+ langerin+ dermal dendritic cells mediate peripheral induction of antigen-specific CD4+ CD25+ ...
Nature 338, 591 (1989). Essential role of T cell receptor-mediated positive selection in T cell survival and lineage fate (CD4/ ... Teho H. S., Kisielow, P., Scott, 8., Kishi, H., Uematsu, Y., Blüthmann, H. and von Boehmer, H.: Thymic MHC antigens and the ... Nature 333, 742-746 (1988); Swat, W., Ignatowicz, L., von Boehmer, H. and Kisielow, P.: Clonal deletion of immature CD4+8+ ... Questions concerned with the role of positive and negative selection of developing T cells by peptide-MHC complexes in the ...
The genes used in such vaccines are usually antigen coding surface proteins from the pathogenic organism. They are then ... October 2003). "LMO2-associated clonal T cell proliferation in two patients after gene therapy for SCID-X1". Science. 302 (5644 ... December 2018). "Multiple Integrated Non-clinical Studies Predict the Safety of Lentivirus-Mediated Gene Therapy for β- ... May 2015). "Nuclear architecture dictates HIV-1 integration site selection". Nature. 521 (7551): 227-31. Bibcode:2015Natur.521 ...
Negative selection in the medulla then obliterates T cells that bind too strongly to self-antigens expressed on MHC molecules. ... "Disappearance of T Cell-Mediated Rejection Despite Continued Antibody-Mediated Rejection in Late Kidney Transplant Recipients" ... Virtual memory T cells differ from the other memory subsets in that they do not originate following a strong clonal expansion ... Negative selectionEdit. Negative selection removes thymocytes that are capable of strongly binding with "self" MHC peptides. ...
... which expand in response to specific antigen (process called "clonal selection"). This specific clonal army then combats the ... De Flora, S.; Grassi, C.; Carati, L. (1997). "Attenuation of influenza-like symptomatology and improvement of cell-mediated ... Thus when an antigen is properly presented to the T lymphocytes by an antigen presenting cell (APC), which displays the antigen ... However, when T cells interacts with an antigen not presented by the APCs, that is very probably not the antigen that an immune ...
MAIT cells can be activated in ways that involve, and do not involve, MR1-mediated antigen presentation. However, MR1- ... they may also undergo clonal expansion in the periphery and establish antigen memory. In this way, MAIT cells display both ... T cells rearrange their TCRs and are subjected to TCR affinity tests as a part of positive selection and negative selection. ... A chemically stable antigen that is functionally similar to 5-OP-RU has also been created. A 2017 study also found that some ...
At the same time it has to ignore any self-antigen and tolerate harmless antigens such as food antigens. The signal ... Each T cell expresses clonal TCRs which recognize a specific peptide loaded on a MHC molecule (pMHC), either on MHC class II on ... However, it is not able to mediate signal transduction itself due to its short cytoplasmic tail, so TCR still requires CD3 and ... Because T cells undergo positive selection in the thymus there is a non-negligible affinity between self pMHC and the TCR, ...
Negative selection in the medulla then obliterates T cells that bind too strongly to self-antigens expressed on MHC molecules. ... Increasing evidence indicates microRNAs, which are small noncoding regulatory RNAs, could impact the clonal selection process ... A T cell, or T lymphocyte, is a type of lymphocyte (a subtype of white blood cell) that plays a central role in cell-mediated ... Positive selection[edit]. Positive selection "selects for" T cells capable of interacting with MHC. Positive selection involves ...
In some cases of sweeping selection (very strong selection for a trait), an individual (or a limited number of individuals) ... multiple synthetic peptide antigens > single peptide antigen. The scarcity of effective synthetic vaccines for RNA viral ... in connection with the issue of clonal versus non-clonal nature of virus evolution (microbial evolution in general). Only a ... For this virus fusion is mediated by two proteins termed H and F. A truncated H was deficient in cell fusion but the activity ...
Within germinal centers, TFH cells play a critical role in mediating the selection and survival of B cells that go on to ... In germinal centers, antigen-experienced TFH cells rapidly upregulate the expression of CD40L, which binds and stimulates the B ... causes B cell antibodies to class switch from IgM/IgD to other antibody isotypes and drives somatic hypermutation during clonal ... Therefore, in the absence of TFH cells, similar to B cell activation by T-cell independent antigens, a quick burst of low ...
... and internalizes offending antigens, which are taken up by the B cell through receptor-mediated endocytosis and processed. ... by selection for the ability to bind antigen with higher affinity, the activation and growth of B cell clones able to secrete ... Surface antigens[edit]. Terminally differentiated plasma cells express relatively few surface antigens, and do not express ... Another important surface antigen is CD319 (SLAMF7). This antigen is expressed at high levels on normal human plasma cells. It ...
Normal body cells are not recognized and attacked by NK cells because they express intact self MHC antigens. Those MHC antigens ... endothelial cells (via passive diffusion/ osmosis & active selection). P-glycoprotein (mechanism by which active transportation ... Tonn T, Becker S, Esser R, Schwabe D, Seifried E (August 2001). "Cellular immunotherapy of malignancies using the clonal ... Cytokines produced by macrophages and other cells of the innate immune system mediate the inflammatory response. These ...
An immunogen is an antigen substance (or adduct) that is able to trigger a humoral (innate) or cell-mediated immune response.[ ... negative selection). Endogenous antigens include xenogenic (heterologous), autologous and idiotypic or allogenic (homologous) ... Antigens can be classified according to their source. Exogenous antigens[edit]. Exogenous antigens are antigens that have ... T-independent antigen - Antigens that stimulate B cells directly.. *Immunodominant antigens - Antigens that dominate (over all ...
T cell expresses clonal TCRs which recognize specific peptide/MHC complex during physical contact between T cell and antigen- ... However, it is not able to mediate signal transduction itself due to its short cytoplasmic tail, so TCR still requires CD3 and ... "Selection of functional T cell receptor mutants from a yeast surface-display library". Proceedings of the National Academy of ... T-cell sensitivity to antigen could be increased via avidity-based mechanism. The antigen sensitivity is higher in antigen- ...
Chang TW, Wu PC, Hsu CL, Hung AF (2007). Anti-IgE antibodies for the treatment of IgE-mediated allergic diseases. Adv. Immunol ... Binding of antigens to IgE already bound by the FcεRI on mast cells causes cross-linking of the bound IgE and the aggregation ... Clonal selection. *V(D)J recombination. *Junctional diversity. *Immunoglobulin class switching. *MHC/HLA ... IgE primes the IgE-mediated allergic response by binding to Fc receptors found on the surface of mast cells and basophils. Fc ...
Mast cells are also involved in mediating inflammation and autoimmunity as well as mediating and regulating neuroimmune system ... they are professional antigen-presenting cells, they regulate other immune cell functions (e.g., CD4+ T cell, dendritic cell, B ... Clonal selection. *V(D)J recombination. *Junctional diversity. *Immunoglobulin class switching. *MHC/HLA ... Mast cells are a type of granulocyte that are present in tissues;[3] they mediate host defense against pathogens (e.g., ...
... any antibody produced against this antigen (which mimics the self-antigens) can also, in theory, bind to the host antigens, and ... Clonal Anergy theory, proposed by Nossal, in which self-reactive T- or B-cells become inactivated in the normal individual and ... Aberrant B cell receptor-mediated feedback - A feature of human autoimmune disease is that it is largely restricted to a small ... Molecular Mimicry - An exogenous antigen may share structural similarities with certain host antigens; thus, ...
Circulating antibodies are produced by clonal B cells that specifically respond to only one antigen (an example is a virus ... Antibodies directed against red blood cell surface antigens in immune mediated hemolytic anemia are detected with the Coombs ... Honjo T, Habu S (1985). "Origin of immune diversity: genetic variation and selection". Annu Rev Biochem. 54 (1): 803-830. doi: ... Antibody-antigen interactions[edit]. The antibody's paratope interacts with the antigen's epitope. An antigen usually contains ...
Instead of acting via antigen-specific receptors, lysis of tumor cells by NK cells is mediated by alternative receptors, ... Tonn T, Becker S, Esser R, Schwabe D, Seifried E (August 2001). "Cellular immunotherapy of malignancies using the clonal ... Infusions of T cells engineered to express a chimeric antigen receptor that recognizes an antigen molecule on leukemia cells ... Cytolytic granule mediated cell apoptosis[edit]. NK cells are cytotoxic; small granules in their cytoplasm contain proteins ...
For example, when an antigen-presenting cell expresses an antigen on MHC class II, a CD4+ cell will aid those cells through a ... CD154, also called CD40 ligand or CD40L, is a cell surface protein that mediates T cell helper function in a contact-dependent ... secretion of IL-2 can bind to that same Th cell or neighboring Th's via the IL-2R thus driving proliferation and clonal ... that a host antigen is foreign. As a result, the CD8+ T cells treat the host cell presenting that antigen as infected, and go ...
... antigens[edit]. There are five (HNA 1-5) sets of neutrophil antigens recognized.[49] The three HNA-1 antigens (a-c) ... In 2007 researchers at the Whitehead Institute of Biomedical Research found that given a selection of sugars, neutrophils ... "Lyn is a redox sensor that mediates leukocyte wound attraction in vivo". Nature. 480 (7375): 109-12. Bibcode:2011Natur.480.. ... The HNA-3 antigen system has two antigens (3a and 3b) which are located on the seventh exon of the CLT2 gene (SLC44A2). The HNA ...
In the mid-1950s, Macfarlane Burnet, inspired by a suggestion made by Niels Jerne,[41] formulated the clonal selection theory ( ... Coutinho A, Forni L, Holmberg D, Ivars F, Vaz N (1984). "From an antigen-centered, clonal perspective of immune responses to an ... Symbiont-mediated defenses are also heritable across host generations, despite a non-genetic direct basis for the transmission ... Burnet FM (1959). The Clonal Selection Theory of Acquired Immunity. Cambridge: Cambridge University Press.. ...
Humans have altered the genomes of species for thousands of years through selective breeding, or artificial selection[19]:1[20] ... In plants the DNA is often inserted using Agrobacterium-mediated transformation,[59] taking advantage of the Agrobacteriums T- ... Bacteria are cheap, easy to grow, clonal, multiply quickly, relatively easy to transform and can be stored at -80 °C almost ... genetic engineering of chimeric antigen receptors on a patient's own T-cells was approved by the U.S. FDA as a treatment for ...
Selection pressure in the environment selects for antigenic changes in the antigen determinants of HA, that includes places ... Wisniewski-Dyé F; Vial L (2008). "Phase and antigenic variation mediated by genome modifications". Antonie van Leeuwenhoek. 94 ... The result is that even a clonal population of pathogens expresses a heterogeneous phenotype.[5] Many of the proteins known to ... Immunity to re-infection is based on recognition of the antigens carried by the pathogen, which are "remembered" by the ...
Age related macular degeneration (AMD) is now believed to be caused, at least in part, by complement mediated attack on ocular ... Clonal selection. *V(D)J recombination. *Junctional diversity. *Immunoglobulin class switching. *MHC/HLA ... and act as a cofactor for Factor I-mediated cleavage of C3b.[3] Complement factor H preferentially binds to vertebrate cells ( ...
It is induced by prior exposure to that specific antigen[1][2] and contrasts with conventional immune-mediated elimination of ... This process of negative selection ensures that T and B cells that could initiate a potent immune response to the host's own ... now termed clonal deletion.[10] Burnet and Medawar were ultimately credited for "the discovery of acquired immune tolerance" ... Peripheral mucosal immune tolerance, in particular mediated by iTreg cells and tolerogenic antigen-presenting cells, is thought ...
Recent studies in mice suggest that basophils may also regulate the behavior of T cells and mediate the magnitude of the ... Clonal selection. *V(D)J recombination. *Junctional diversity. *Immunoglobulin class switching. *MHC/HLA ... pollen proteins or helminth antigens. ...
Disappearance of T Cell-Mediated Rejection Despite Continued Antibody-Mediated Rejection in Late Kidney Transplant Recipients. ... MR1 antigen presentation to mucosal-associated invariant T cells was highly conserved in evolution. Proceedings of the National ... Zerrahn, J.; Held, W.; Raulet, D. H. The MHC reactivity of the T cell repertoire prior to positive and negative selection. Cell ... 克隆清除(英语:Clonal deletion). *免疫缺陷 ... An induced rebinding model of antigen discrimination. Trends ...
However, all bacteria can evolve by selection on changes to their genetic material DNA caused by genetic recombination or ... Bacteria, as asexual organisms, inherit an identical copy of the parent's genomes and are clonal. ... Beachey EH (March 1981). "Bacterial adherence: adhesin-receptor interactions mediating the attachment of bacteria to mucosal ... antigens and quinones.[103] While these schemes allowed the identification and classification of bacterial strains, it was ...
Antibody-antigen reaction[edit]. Now these antibodies will encounter antigens and bind with them. This will either interfere ... It contrasts with cell-mediated immunity. Its aspects involving antibodies are often called antibody-mediated immunity. ... Clonal selection. *V(D)J recombination. *Junctional diversity. *Immunoglobulin class switching. *MHC/HLA ... When a B cell encounters an antigen, it is bound to the receptor and taken inside by endocytosis. The antigen is processed and ...
However, a selection process[further explanation needed] leads to a predominant transmission of the R5 virus through this ... This cleavage is mediated by the packaged viral protease and can be inhibited by antiretroviral drugs of the protease inhibitor ... Wyatt R, Sodroski J (1998). "The HIV-1 envelope glycoproteins: fusogens, antigens, and immunogens". Science. 280 (5371): 1884-8 ... and the clonal composition of virus populations in the course of human immunodeficiency virus type 1 infection". The Journal of ...
... whereas antigen-activated B cells are intercepted and undergo clonal expansion within the FDC networks, generating germinal ... Adhesion between FDCs and B cells is mediated by ICAM-1 (CD54)-LFA-1 (CD11a) and VCAM-VLA-4 molecules. Activated B-cells with ... positive and negative selection, isotype switching, and differentiation into high-affinity plasma cells and memory B cells. ... Noncognate (not antigen specific) B cells play a significant role in the transport of antigens to FDCs. They capture immune ...
December 2003). "An immunologically privileged retinal antigen elicits tolerance: major role for central selection mechanisms ... Tissue destruction is mediated by non-specific macrophage activation and the resulting cytokine cascades. Serum TNF-α is ... and cellular stress is normally suppressed by myeloid suppression while inducible Treg cells prevent activation and clonal ... The most common antigens include HLA-B27, HLA-A29 (in birdshot chorioretinopathy) and HLA-B51 (in Behçet disease).[citation ...
... and therefore are able to transplant the organ without immediate rejection by removal of the antigen. However, the antigen ... Cre has proven to be a key element in a process known as recombination-mediated cassette exchange (RMCE). While it has shown to ... They were persistent over a 6-year study period, without herbicide selection pressure and despite hybridization with the wild ... 17 October 2003). "LMO2-Associated Clonal T Cell Proliferation in Two Patients after Gene Therapy for SCID-X1". Science. 302 ( ...
Clonal Selection, Antigen-Mediated* * Humans * Leukemia* / diagnosis * Leukemia* / immunology * Leukemia* / metabolism * Models ... Model results imply that enhanced self-renewal may be a key mechanism in the clonal selection process. Simulations suggest that ... Clonal selection and therapy resistance in acute leukaemias: mathematical modelling explains different proliferation patterns ... We propose a new mathematical model to investigate the impact of cell properties on the multi-clonal composition of leukaemias ...
In these cases the nature of the antigen is the major variable. ... 1-8. Clonal selection of lymphocytes is the central principle ... 1-7. Lymphocytes activated by antigen give rise to clones of antigen-specific cells that mediate adaptive immunity ... Endogenous superantigens mediate negative selection of T-cell receptors derived from particular Vβ gene segments ... 3-9 Antigen-antibody interactions involve a variety of forces. *3-10 The antigen receptor on T cells is very similar to a Fab ...
The Immune System Works by Clonal Selection *Most Antigens Stimulate Many Different Lymphocyte Clones ... The Cadherins Mediate Ca2+-dependent Cell-Cell Adhesion in Vertebrates *Cadherins Mediate Cell-Cell Adhesion by a Homophilic ... Immunological Memory Is Due to Clonal Expansion and Lymphocyte Maturation *The Failure to Respond to Self Antigens Is Due to ... The Strength of an Antibody-Antigen Interaction Depends on Both the Number of Antigen-binding Sites Occupied and the Affinity ...
Clonal selection raises the clonal frequency of cells with a particular antigen specificity rather than all cells. This means ... Effector phase - humoural and cell-mediated immunity, elimination of antigen. Decline homeostasis - T and B cell apoptosis. ... Recognition phase - clonal selection and expansion Activation phase - differentiation to effector cells. ... Who saw the link between cell mediated and humour all immunity and when? ...
This process is called clonal selection because only the TH cells that recognize the foreign invader are selected to reproduce ... The APC "shows" the antigen to the TH cells until there is a match between a TH cell receptor and the antigen. The contact ... Two parts of adaptive immunity meet this challenge: cellular-mediated immunity and humoral (antibody-mediated immunity). ... After an antigen is cleared from the body, immunological memory allows an antigen to be recognized and removed more quickly if ...
Cell-mediated immunity and antibody-mediated immunity. Whats clonal selection?. Process by which a lymphocyte proliferates ( ... Aka human leukocyte antigens. What is the functions of antigen presenting cells and name few?. Lymphocyte that begins ... What is MHC antigen?. Major histocompatibility complex antigen. Surface proteins on white blood cells & other nucleated cells ... Whats the difference between a complete antigen and a hapten? Give an example.. A complete antigen has both reactivity and ...
How humoral immunity works and how cell mediated immunity works. How vaccination and vaccines lead to a primary immune response ... Clonal selection. The process by which the B cells will make the right antibody to inactivate or destroy a particular pathogen ... The antigens are combined with special proteins called the major histocompatibility complex (MHC). The antigen/MHC complexes ... Cell-mediated system. The response of the immune system to body cells that have changed in some way e.g. have been infected by ...
Clonal Selection Clonal Selection: Selection: B cells (and T cells) that encounter stimulating antigen will proliferate into a ... Cell Mediated Immunity is Carried Out by T Lymphocytes .. Microbes: Microbes: Capsules. etc.Antigens Most are proteins or large ... Clonal selection increases number of T cells. and reacts to a specific antigen (T cell receptor). T cells have an antigen ... Clonal Selection: Selection: When a B cell encounters an antigen it recognizes. After maturation B cells migrate to lymphoid ...
In 1957, Burnet put forth his clonal selection theory to explain the biology of immune responses. On meeting an antigen, an ... Cell-mediated immune responses involve several events following the entry of antigen. Helper T cells are required, so some of ... In 1957, Burnet put forth his clonal selection theory to explain the biology of immune responses. On meeting an antigen, an ... Few antigens bind directly to antigen-reactive T- or B-cells but are presented to the lymphocytes bound to other antigen ...
Recruitment and selection of marginal zone B cells is independent of exogenous antigens. Eur. J. Immunol. 35: 2089-2099. ... Clonal selection and learning in the antibody system. Nature 381: 751-758. ... Antigen-specific B cells efficiently present low doses of antigen for induction of T cell proliferation. J. Immunol. 135: 980- ... 3⇑E) following BCR-mediated internalization, does this result in MHC class II-mediated presentation of Salmonella Ags? To test ...
Describe the mechanism of clonal selection. 12. Describe the cellular basis for immunological memory. 13. Describe the cellular ... and explain what happens when they are activated by antigens. 10. Explain how a single antigen molecule may stimulate the ... Explain how humoral immunity and cell-mediated immunity differ in their defensive activities. 9. Describe where T and B cells ... Recognize and bind to antigens b. Assist in destruction and elimination of antigens 16. List the five major classes of ...
... antigen-driven clonal selection, and humoral immunity. B-cell receptor signaling activates PI3K-mediated activation of the ... Chimeric Antigen Receptor T Cells in Refractory B-Cell Lymphomas. N Engl J Med. 2017 Dec 28. 377 (26):2545-2554. [Medline]. ... Dal Porto JM, Gauld SB, Merrell KT, Mills D, Pugh-Bernard AE, Cambier J. B cell antigen receptor signaling 101. Mol Immunol. ... Thome M, Charton JE, Pelzer C, Hailfinger S. Antigen receptor signaling to NF-kappaB via CARMA1, BCL10, and MALT1. Cold Spring ...
... antigen-driven clonal selection, and humoral immunity. B-cell receptor signaling activates PI3K-mediated activation of the ... Chimeric Antigen Receptor T Cells in Refractory B-Cell Lymphomas. N Engl J Med. 2017 Dec 28. 377 (26):2545-2554. [Medline]. ... Dal Porto JM, Gauld SB, Merrell KT, Mills D, Pugh-Bernard AE, Cambier J. B cell antigen receptor signaling 101. Mol Immunol. ... Thome M, Charton JE, Pelzer C, Hailfinger S. Antigen receptor signaling to NF-kappaB via CARMA1, BCL10, and MALT1. Cold Spring ...
T-CELL MEDIATED IMMUNITY (cont.)*Clonal selection determines proliferation of T cells that carry out cell-mediated immunity ... CLONAL DELETION*During fetal development, clones of lymphocytes that react with self antigens are eliminated (self-tolerance) ... K antigen (acidic polysaccharides) of E. coli or the analogous Vi antigen of Salmonella typhi ... Specific Defenses of the Host: The Immune Response -Immunogen : a substance that induces a specific immune response antigen (ag ...
Antigens, antibodies, antigen receptors, antigenic determinants - Clonal selection • Effector and memory cells - Primary vs. ... Secondary infections - Lymphocytes • B-cells and T cells - Humoral immunity - Cell mediated immunity • Book problems - 1, 2, 3 ... Secondary immune response Cell mediated immunity Chapter 27 content and book questions ... Natural selection - Genetic drift, - Small population size - Gene flow between populations - Non random mating ...
Clonal selection theory. Jerne, Talmage and Burnet in the late 1950s found the clonal selection theory. This proved all the ... James Gowans in 1959 showed that lymphocytes had a role in mediating both cell-mediated and humoral responses. ... The biochemical properties of antigen-antibody binding interactions were examined in more detail in the late 1930s by John ... Cell-mediated immunity and humoral immunity. Related Stories. *Early monoclonal antibody therapies beneficial for COVID-19, ...
... in which B-cell clonal selection may arise. B-cell clonal expansion starts as an antigen-driven event and expands towards ... Among them, complement factors play a crucial role in the cold-insoluble ICs-mediated vasculitis, involving primarily small ...
... antigen-driven clonal selection, and humoral immunity. B-cell receptor signaling activates PI3K-mediated activation of the ... antigen-driven clonal selection, and humoral immunity. Structurally, the BCR consists of antigen-binding IgH and immunoglobulin ... 66] Upon antigen stimulation, clustering of the BCRs occurs, leading to signal transduction via the CD79A and B subunits. [67] ... Chimeric Antigen Receptor T Cells in Refractory B-Cell Lymphomas. N Engl J Med. 2017 Dec 28. 377 (26):2545-2554. [Medline]. ...
... antigen-driven clonal selection, and humoral immunity. B-cell receptor signaling activates PI3K-mediated activation of the ... Chimeric antigen receptor (CAR) T-cell therapy utilizes each patients own T cells, extracted by leukapheresis. The T cells are ... Dal Porto JM, Gauld SB, Merrell KT, Mills D, Pugh-Bernard AE, Cambier J. B cell antigen receptor signaling 101. Mol Immunol. ... Thome M, Charton JE, Pelzer C, Hailfinger S. Antigen receptor signaling to NF-kappaB via CARMA1, BCL10, and MALT1. Cold Spring ...
Result of clonal selection. Carry out immune response to destroy or deactivates antigen.. Gets shit done. Then dies.. Active ... Cell Mediated. AKA Delayed hypersensitivity. 12-72 hours after exposure, immunocompetent T cells return to site and stimulate ... Result of clonal selection. Do not actively participate in initial immune response. Response quicker in subsequent invasion. ... Self-antigens. AKA human leukocyte antigens (HLA). Help T cells recognize cell as self/foreign ...
If the antigen reappears in the body, both cell-mediated and antibody-mediated immune responses are much quicker and intense; ... Once activated, the cytotoxic T cells undergo clonal selection and expansion into active and memory cytotoxic T cells. The ... 2.3.2. Cell-Mediated Immunity. During cell-mediated immunity, activated T cells kill host cells that present foreign antigens ... molecules at the cell surface that present self-antigens, while class II MHC (MHC-II) antigens appear on the surface of antigen ...
Complex antigens drive permissive clonal selection in germinal centers. Immunity. 44:542-552. doi:10.1016/j.immuni.2016.02.010 ... ICAM-mediated selection of B cells for clonal expansion confers an advantage during early stages of the response, before GC ... and thereby facilitate the selection of B cells for clonal expansion. Based on our antigen targeting experiments as well as ... B cell clonal selection is thought to depend on stringent T cell-dependent selection that promotes GC colonization by B cells ...
Clonal Selection. In clonal selection, an antigen is presented to many circulating naive B and (via MHC) T cells, and the ... Cell-Mediated Immune Response. Clonal Selection and T-Cell Differentiation. Antigens are selected to form clones of themselves ... Clonal selection is used during negative selection to destroy lymphocytes that may be able to bind with self antigens. ... Clonal selection is the theory that specific antigen receptors exist on lymphocytes before they are presented with an antigen ...
... response that is mediated by T- and B-lymphocytes and antibodies. Fishes are the first vertebrates where clonal selection and ... B cells in fishes have been characterized through the expression of antigen receptor (BCR). In fishes, IgM is the main soluble ... SOCS3 mediates inhibition of phosphorylation of STAT5, which has been related with the diminishment of cellular proliferation [ ... D. Kägi, F. Vignaux, B. Ledermann et al., "Fas and perforin pathways as major mechanisms of T cell-mediated cytotoxicity," ...
... developing T cells have undergone extensive selection within the thymus as well as post-thymic antigen-mediated clonal ... was not associated with clonal selection or expansion in vivo. Clonal analysis of long-term repopulating cell progeny in vivo ... Finally, it is possible that antigen-mediated skewing of the T cell repertoire would alter the representation of RISs, although ... Multilineage hematopoietic reconstitution without clonal selection in ADA-SCID patients treated with stem cell gene therapy. ...
The clonal selection theory implies that . antigens activate specific lymphocytes. The protection provided through transfer of ... The allergic response is primarily mediated by _____ antibodies. IgE In mammalian defenses against invading pathogens, all of ... Antigens are non-self proteins. . Which of the following is true of both T cells and B cells? All of these statements are true ... Which of the following statements about antibody-mediated immunity is CORRECT? It defends against parasites, bacteria, and ...
The enriched CD4-positive cells were subjected to limited dilution for clonal selection. Isolated cell colonies arising from a ... CCE is mediated by the oligomerization of stromal interaction molecule (STIM) upon ER Ca2+ store depletion and its subsequent ... Successful transformants, which carried CD4 surface antigen, were enriched by Dynabeads CD4 Positive Isolation Kit (Invitrogen ... Generation of CRISPR-mediated knockout SH-SY5Y cells. CRISPR/Cas9-based genome editing was performed on SH-SY5Y cells to ...
A promising application is the use of antibody profiling to guide development and selection of antigen-specific therapies to ... Major barriers to development of antigen-specific therapies for T-cell-mediated autoimmune diseases, such as multiple sclerosis ... analysis of the antibody repertoires revealed clonal families of heavy-chain sequences and enabled rational selection of ... Antigen arrays for antibody profiling CURRENT OPINION IN CHEMICAL BIOLOGY Robinson, W. H. 2006; 10 (1): 67-72 Abstract. Antigen ...
... amongst billions based on its antigen specificity is called clonal selection (Figure 3). This process allows the immune system ... Their receptors are used only for the detection of foreign antigens, and do not directly mediate an effector response. So even ... IC system I: Clonal selection. The first system Behe describes in chapter 6 is the process of clonal selection, which is how ... Clonal Selection - Behe lists three components as part of the clonal selection systems "core": the membrane-bound ...
... amongst billions based on its antigen specificity is called clonal selection (Figure 3). This process allows the immune system ... Their receptors are used only for the detection of foreign antigens, and do not directly mediate an effector response. So even ... Clonal Selection - Behe lists three components as part of the clonal selection systems "core": the membrane-bound ... Behe has this to say about the evolution of the clonal selection system:. "A cell hopefully trying to evolve such a system in ...
  • These organs contain large numbers of antigen-presenting cells (APCs), T lymphocytes (or T cells ), and B lymphocytes (or B cells). (encyclopedia.com)
  • Response: Involves production of antibodies and generation of specialized lymphocytes against specific antigens. (scribd.com)
  • Cell Mediated Immunity Involves specialized set of lymphocytes called T cells that recognize foreign antigens on the surface of cells. (scribd.com)
  • Engagement of this receptor is requisite for lymphocyte activation, so a given antigen activates only those lymphocytes whose receptors bind well, yielding appropriate specificity in the overall response. (encyclopedia.com)
  • Antigen recognition by lymphocytes. (encyclopedia.com)
  • James Gowans in 1959 showed that lymphocytes had a role in mediating both cell-mediated and humoral responses. (news-medical.net)
  • Clonal selection is used during negative selection to destroy lymphocytes that may be able to bind with self antigens. (lumenlearning.com)
  • Clonal selection is the theory that specific antigen receptors exist on lymphocytes before they are presented with an antigen due to random mutations during initial maturation and proliferation. (lumenlearning.com)
  • After antigen presentation, selected lymphocytes undergo clonal expansion because they have the needed antigen receptor. (lumenlearning.com)
  • The idea that lymphocytes have antigen-specific binding receptors before they encounter with an antigen, and are selected to proliferate because they have the specific antigen receptor needed during an adaptive immune response. (lumenlearning.com)
  • Clonal selection is an theory that attempts to explain why lymphocytes are able to respond to so many different types of antigens. (lumenlearning.com)
  • Clonal selection assumes that lymphocytes are selected during antigen presentation because they already have receptors for that antigen. (lumenlearning.com)
  • In clonal selection, an antigen is presented to many circulating naive B and (via MHC) T cells, and the lymphocytes that match the antigen are selected to form both memory and effector clones of themselves. (lumenlearning.com)
  • The theoretical basis of clonal selection is the assumption that lymphocytes bearing an antigen receptor for an antigen exist long before antigen presentation occurs, explained by the idea of random mutations (VDJ recombination) that occur during lymphocyte maturation. (lumenlearning.com)
  • During antigen presentation, pre-existing lymphocytes that bear that antigen receptor are merely selected because they can bind with that antigen. (lumenlearning.com)
  • It is also assumed that most lymphocytes never encounter the antigen for which they bear a receptor. (lumenlearning.com)
  • This assumes that random mutations resulted in lymphocytes that were autoreactive instead of reactive to non-self antigens. (lumenlearning.com)
  • Clonal selection of lymphocytes: 1) A hematopoietic stem cell undergoes differentiation and genetic rearrangement to produce 2) immature lymphocytes with many different antigen receptors. (lumenlearning.com)
  • Those that bind to 3) antigens from the body's own tissues are destroyed, while the rest mature into 4) inactive lymphocytes. (lumenlearning.com)
  • antigens activate specific lymphocytes. (studystack.com)
  • The adaptive immune response itself has two components, the humoral response (the synthesis of virus-specific antibodies by B lymphocytes) and the cell-mediated response (the synthesis of specific cytotoxic T lymphocytes that kill infected cells). (lehigh.edu)
  • The theory that lymphocytes bear antigen receptors before activation and that random mutations during clonal expansion cause the development of lymphocytes with high binding affinities for their antigens. (lumenlearning.com)
  • B cells are lymphocytes that play a large role in the humoral immune response (as opposed to the cell-mediated immune response, which is governed by T cells). (lumenlearning.com)
  • They argue that this unique pattern of V domain somatic mutation may require multiple rounds of mutation and selection of B lymphocytes in the germinal centers, the anatomical structures within secondary lymphoid organs that are the main sites for somatic hypermutation and affinity maturation of immunoglobulin genes in B cells. (evmedreview.com)
  • LYMPHOCYTE ACTIVATION by a specific ANTIGEN thus triggering clonal expansion of LYMPHOCYTES already capable of mounting an immune response to the antigen. (bvsalud.org)
  • As a result of T-lymphocytes recognizing epitopes of protein antigens during cell-mediated immunity, numerous circulating T8-memory cells and T4-memory cells) develop which possess anamnestic response or memory. (sem-web.org)
  • Cell-mediated immunity is a type of adaptive immune response that does not involve antibodies but it does involve the activation of NK cell and macrophages and the production of antigen-specific cytotoxic T-lymphocytes and the release of several cytokines in response to a foreign antigen. (sem-web.org)
  • T cells (lymphocytes) bind to the surface of other cells that display the antigen and trigger a response. (sem-web.org)
  • cell-mediated immunity Action by the immune system involving T cells (T LYMPHOCYTES) and concerned with protection against viruses, fungi, TUBERCULOSIS and cancers and rejection of foreign grafted material. (sem-web.org)
  • Our results establish a direct link between the affinity of the T-cell receptor for self-antigens and the proper development of a unique population of lymphocytes that has been implicated in the modulation of a multitude of immune responses in mice and humans. (pnas.org)
  • Be able to describe the model presented in clonal selection theory for how certain B and T lymphocytes are selected for proliferation. (wikipremed.com)
  • Here, the clonal-selection theory, which hypothesized that lymphocytes are diverse and that each is unique, or clonal, was becoming increasingly accepted. (vetscite.org)
  • The process by which antigen is presented to lymphocytes in a form they can recognize. (harvard.edu)
  • In contrast, antigen receptors on B and T lymphocytes diversify enormously in each individual: genes for these receptors composed of multiple various parts are assembled randomly through gene recombination during development of these cells throughout the life of the individuals. (springer.com)
  • Each antigen, by binding to specific receptors, selectively activates a tiny fraction of cells from the bodys diverse pool of lymphocytes this relatively small number of selected cells gives rise to clones of thousands of cells, all specific for and dedicated to eliminating the antigen. (powershow.com)
  • Dendritic cells acquire and present antigens to lymphocytes to activate them. (scioly.org)
  • Adaptive immune responses consist of distinct phases, the first three being the recognition of antigen, the activation of lymphocytes, and the elimination of antigen (the effector phase). (aspeneducationgroup.com)
  • The response contracts (declines) as antigen-stimulated lymphocytes die by apoptosis, restoring homeostasis, and the antigen-specific cells that survive are responsible for memory. (aspeneducationgroup.com)
  • These principles apply to humoral immunity (mediated by B lymphocytes) and cell-mediated immunity (mediated by T lymphocytes). (aspeneducationgroup.com)
  • Lymphocytes specific for a large number of antigens exist before exposure to the antigen, and when an antigen enters, it selects the specific cells and activates them (Fig. 1-7). (aspeneducationgroup.com)
  • According to this hypothesis, antigen-specific clones of lymphocytes develop before and independent of exposure to antigen. (aspeneducationgroup.com)
  • The nature of the antigen that activates T cells (i.e., peptides bound to MHC molecules) ensures that these lymphocytes can interact only with other cells (because MHC molecules are cell surface proteins) and not with free antigen. (aspeneducationgroup.com)
  • B lymphocytes use their antigen receptors (membrane-bound antibody molecules) to recognize antigens of many different chemical types. (aspeneducationgroup.com)
  • Activated CD4+ helper T lymphocytes proliferate and differentiate into effector cells whose functions are mediated largely by secreted cytokines. (aspeneducationgroup.com)
  • IL-2 is a growth factor that acts on the antigen-activated lymphocytes and stimulates their proliferation (clonal expansion). (aspeneducationgroup.com)
  • Each antigen (X or Y) selects a preexisting clone of specific lymphocytes and stimulates the proliferation and differentiation of that clone. (aspeneducationgroup.com)
  • In contrast, the adaptive immune response is made up of B and T lymphocytes that have unique receptors specific to various microbial antigens. (jyi.org)
  • In the peripheral lymphoid organs, the potential of unlimited activation and expansion of lymphocytes in response to antigens is primarily regulated by apoptosis and anergy. (elsevier.com)
  • Two inhibitory molecules, CD152 (CTLA-4) and CD85/LIR-1/ILT2 are expressed in all T cells, being largely confined within intracellular compartments of these lymphocytes when they are in a resting state, but ready to be shuttled to and from the plasma membrane when cells are activated following encounter with antigen. (elsevier.com)
  • However, routes of antigen transport, trafficking of lymphocytes and distinctive cell populations decide the task of a specific secondary lymphoid tissue during immune responses to different foreign antigens including transplanted organs. (aegisinteractive.com)
  • While the initial recognition of a specific Ag is mainly done by cells belonging to the lymphocytes lineage, additional accessory cells are needed for Antigen A substance that when introduced into the body (non-self antigens as chemicals, toxins, bacteria, or viruses), stimulates the immune system to produce antibodies." class="glossaryLink ">antigen processing and presentation, as well as secreted mediators, or cytokines, required for the proliferation, interaction and regulation of immune cells. (necropsymanual.net)
  • Cell-mediated immunity (CMI) is the type of adaptive immunity that is mediated by specific subpopulations of T-lymphocytes called effector T-cells. (quadri-canvas.it)
  • Receptors are cell surface proteins that can attach to antigens. (encyclopedia.com)
  • Like T H cells, each T C cell and B cell has receptors that match one antigen. (encyclopedia.com)
  • Simply put, while billions of different antigen receptors can be made (in terms of antigen-binding specificity), each lymphocyte makes only one kind. (encyclopedia.com)
  • B cells mature in the bone marrow, where they undergo VDJ recombination to produce unique receptors that do not react to self-antigens. (lumenlearning.com)
  • The immature B cells whose receptors (BCRs) bind too strongly to self antigens will not be killed. (lumenlearning.com)
  • When the B cell receptor on the cell surface matches its cognate antigen in the body, the B cell proliferates and secretes a free form of those receptors ( antibodies ), with identical binding sites as on the original cell surface. (lumenlearning.com)
  • B cell activation refers to the differentiation and clonal expansion of B cells.When the B cell receptor on the cell surface matches its cognate antigen in the body, the B cell proliferates and secretes a free form of those receptors (antibodies) in the body, with binding sites identical to those on the original cell surface. (lumenlearning.com)
  • begins when specific antigen binds to B cell receptors, activating B cells. (studymode.com)
  • Another surprise is that such diverse receptors in an individual do not react with any structures contained in the self body (self-antigens) in principle, which is called self-tolerance. (springer.com)
  • According to a modern interpretation of the clonal selection hypothesis, multiple clones of immunocompetent cells displaying unique antigen-specific receptors exist prior to interaction with antigens and in the case of T cells get selected on the basis of interaction with self-peptides bound to MHC molecules in the thymus. (jci.org)
  • The majority of thymocytes bearing high-affinity receptors for self-antigens are eliminated centrally during thymic differentiation by an apoptotic mechanism termed negative selection. (jci.org)
  • Engagement of antigen receptors and other signals trigger lymphocyte proliferation and differentiation. (aspeneducationgroup.com)
  • These antigen-specific receptors are encoded by genes generated during a complex of gene rearrangement that occurs during the course of lymphocyte development. (jyi.org)
  • The innate response relies on the recognition of constitutional products of the organisms that have been preserved over the course of evolution, mediated by receptor proteins called PRRs (" pathogen or pattern recognition receptors"), which distinguish infectious no self, from non- infectious self. (necropsymanual.net)
  • Our data are consistent with an innate-like antiviral recognition system mediated by B cells using defined germ-line coded B cell receptors, which could provide a rapid germinal center-independent antibody response during the early phase of infection. (beds.ac.uk)
  • Current techniques, however, are limited in their ability to elucidate essential immune cell features, including the variable sequences of T cell receptors (TCRs) that confer antigen specificity in T cells. (researchsquare.com)
  • Parasite-derived proteins expressed on the surface of erythrocytes infected with Plasmodium falciparum are important virulence factors, since they mediate binding of infected cells to diverse receptors on vascular endothelium and are targets of a protective immune response. (pnas.org)
  • This is why the immune system can recognize millions of antigens with specificity. (encyclopedia.com)
  • B cells are unique in their ability to generate antibodies against infectious pathogens and refine their specificity in multiple rounds of mutation and clonal selection ( 1 ). (aacrjournals.org)
  • During B cell clonal expansion, many copies of that B cell are produced that share affinity with and specificity of the same antigen. (lumenlearning.com)
  • The recognition specificity of different non-self-antigens or defective self-antigens (tumors) by a well-defined B-cell clone does not result from the presence of an extensive number of receptor genes, but rather from immunogenetic mechanisms affecting a limited number of IG genes, including mechanisms of genetic recombination, mutations, deletions or insertions, and gene repair, through very complex regulatory mechanisms that are responsible for a large B-cell repertoire. (intechopen.com)
  • Antigen recognition provides specificity to the immune response, and the need for costimulation ensures that T cells respond to microbes (the inducers of costimulatory molecules) and not to harmless substances. (aspeneducationgroup.com)
  • Although it constitutes the determinative group and can bind antigen, hapten cannot stimulate a full immune response without being carried by a larger protein molecule superantigen- bacterial toxins that are potent stimuli for T cells and can be a factor in diseases such as toxic shock epitope- the precise molecular group of an antigen that defines its specificity and triggers the immune response. (aegisinteractive.com)
  • The vertebrate immune system has solved the specificity problem by initially generating a more or less random repertoire, which, during a phase of early development, is limited by a filtering process, called tolerance induction: cells raised against self antigens are excluded from the mature immune system. (sciencemag.org)
  • Each T H cell has a different receptor, allowing each cell to recognize a different antigen. (encyclopedia.com)
  • The APC "shows" the antigen to the T H cells until there is a match between a T H cell receptor and the antigen. (encyclopedia.com)
  • The cells with the appropriate receptor encounter the antigen, preparing them for activation. (encyclopedia.com)
  • The B lymphocyte's antigen receptor is a membrane-bound version of the antibody it will secrete if activated. (encyclopedia.com)
  • In contrast, a T lymphocyte's antigen receptor (TcR) is not secreted, but instead binds antigen displayed on the surface of other cells. (encyclopedia.com)
  • Following T cell maturation, naive T cells circulate through the circulatory and lymphatic systems of the body until presented with an antigen for which they bear the receptor. (lumenlearning.com)
  • T cell independent activation occurs when antigens directly bind to B cell themselves, usually through cross-linking the antigen to the B cell receptor or receiving the antigen with a toll-like receptor. (lumenlearning.com)
  • We demonstrate that strict "Goldilocks" conditions of affinity for self-lipids by the T-cell antigen receptor expressed on T-cell precursors are necessary for imprinting the proper developmental program toward the invariant NK T-cell lineage. (pnas.org)
  • The self-reactivity of their T-cell antigen receptor (TCR) is thought to contribute to the development of immune regulatory cells, such as invariant NK T cells (iNKT). (pnas.org)
  • The generation of antigen receptor diversity, and thus of the B-cell repertoire, is the result of very complex immunogenetic mechanisms. (intechopen.com)
  • This chapter focuses on the molecular description of the immunogenetic mechanisms responsible for the generation of B-cell antigen receptor diversity. (intechopen.com)
  • Understand the mechanisms of the CD (cluster of differentiation) system, MHC (major histocompatibility complex), B cell receptor, and T cell receptor in antigen presentation and recognition. (wikipremed.com)
  • Each cell carries a unique surface receptor that, when bound by antigen, triggers the proliferation of that clone. (vetscite.org)
  • While T-cell antigen receptor (TCR) recognizes antigenic peptides of proteins presented on the self MHC, B-cell antigen receptor (BCR) recognizes essentially any kinds of molecules. (springer.com)
  • Aiba Y, Oh-hora M, Kiyonaka S, Kimura Y, Hijikata A, Mori Y, Kurosaki T (2004) Activation of RasGRP3 by phosphorylation of Thr-133 is required for B-cell receptor-mediated Ras activation. (springer.com)
  • Brummer T, Shaw PE, Reth M, Misawa Y (2002) Inducible gene deletion reveals different roles for B-Raf and Raf-1 in B-cell antigen receptor signalling. (springer.com)
  • Cherukuri A, Cheng P, Sohn H, Pierce S (2001b) The CD19/CD21 complex functions to prolong B-cell antigen receptor signaling from lipid rafts. (springer.com)
  • The ability of heterozygous lymphoid cells to produce only one allelic form of antigen-specific receptor when they have the genetic endowment to produce both. (rxpgonline.com)
  • In T-Cell Independent B-Cell Activation free floating antigen binds directly to the antibodies B-Cell Receptor on the surface of the B-cell. (aegisinteractive.com)
  • T cell proliferation in vivo is presumed to reflect a T cell receptor (TCR)-mediated polyclonal response directed to various environmental antigens. (semanticscholar.org)
  • To study antigen-specific T cells comprehensively, two sequencing-based approaches have emerged: 1) bulk genomic sequencing of T cell receptor (TCR) repertoires to assess clonal diversity, and 2) RNA-Sequencing (RNA-Seq) to reveal phenotypic attributes. (researchsquare.com)
  • Cell-signalling molecules that activate cells in both the humoral and the cell-mediated immune responses. (abpischools.org.uk)
  • Antigen: Antigen: Molecules from a pathogen or foreign organism that provoke a specific immune response. (scribd.com)
  • Furthermore, cell-mediated immunity may also destroy cells making aberrant forms or amounts of normal molecules, as in some cancers. (encyclopedia.com)
  • Antigen presentation occurs when degradation products of protein antigens become attached to molecules encoded by a group of genes called the Major Histocompatibility Complex (MHC) and displayed on cell surfaces. (encyclopedia.com)
  • T cells with low-to-intermediate avidity for self-peptide/MHC class I or class II are positively selected and differentiate into mature CD8 + or CD4 + T cells while other T cells with high avidity for self-peptide/MHC molecules are eliminated by negative selection. (rupress.org)
  • Antibody variable (V) domains, found on both of the constituent polypeptide chains composing antibody molecules, i.e. heavy and light chains, are the structures containing the sites that bind to antigens. (evmedreview.com)
  • To respond, the T cells need to recognize not only antigens but also other molecules, called costimulators, which are induced on the APCs by microbes. (aspeneducationgroup.com)
  • To maintain the synergism between the kind of immunity conferred by the vaccines and the cellular location of the included antigens, new findings are gathered about the virulence factors such as toxins, adhesins, invasins (mostly enzymes), anti-apoptotic factors, anti-phagocytic factors, and many more molecules that aid in pathogenesis and invasiveness. (jyi.org)
  • In the studies herein reported, emphasis will be given to surface membrane molecules that down-regulate T-cell-mediated immune responses. (elsevier.com)
  • These molecules control interactions between T cells and antigen presenting cells (APC's) or target (virus-infected or mutated) cells that have to be killed. (elsevier.com)
  • Two sets of molecules exist that either upregulate (coactivation molecules) or down-regulate (inhibitory molecules) T-cell mediated responses. (elsevier.com)
  • The latter aspect of the immune regulation, i.e. molecules that limit the expansion of T-cell clones following specific recognition of antigens will be considered in depth. (elsevier.com)
  • A specialized type of cell, bearing cell surface class II MHC (major histocompatibility complex) molecules, involved in processing and presentation of antigen to inducer, or helper , T cells. (rxpgonline.com)
  • These self-antigens are expressed by thymic cortical epithelial cells on molecules on the surface of cortical epithelial cells. (aegisinteractive.com)
  • While B-cells react to toxin molecules and to the outer surfaces of microbes, T-cells are able to discover the antigens of hidden inner pathogens. (christianhubert.com)
  • In turn, B-cells attach antigens to MHC molecules and display them on the cell surface, in order for T-cells to respond to them. (christianhubert.com)
  • Because this must happen through cell-to-cell contact, it is called cell-mediated immunity (or cellular immunity). (encyclopedia.com)
  • This type of immune response is called antibody -mediated immunity (or humoral immunity). (encyclopedia.com)
  • What provides cell-mediated immunity? (studystack.com)
  • Types of Acquired Immunity I. Body generates an immune response to antigens. (scribd.com)
  • Naturally Acquired Active Immunity: Immunity: Antigens or pathogens enter body naturally. (scribd.com)
  • 1. Artificially Acquired Active Immunity: Immunity: Antigens are introduced in vaccines (immunization). (scribd.com)
  • Humoral (Antibody-Mediated) Immunity (Antibody Involves production of antibodies against foreign antigens. (scribd.com)
  • Being facultative intracellular pathogens, immunity to Salmonella requires adequate humoral and cell-mediated immune responses ( 16 , 17 ). (jimmunol.org)
  • 8. Explain how humoral immunity and cell-mediated immunity differ in their defensive activities. (coursehero.com)
  • 19. Design a flow chart describing the sequence of events that follows the interaction between antigen presenting macrophages and helper T cells, including both cell-mediated and humoral immunity. (coursehero.com)
  • Thereafter cell-mediated immunity was found and recognized as different from humoral immunity in 1942 when Merrill Chase successfully transferred immunity against tuberculosis between pigs by transferring white blood cells. (news-medical.net)
  • Which of the following statements about antibody-mediated immunity is CORRECT? (studystack.com)
  • Adaptive immunity is an immunity that occurs after exposure to an antigen either from a pathogen or a vaccination. (oercommons.org)
  • during his period of leadership the school became an international centre for the analysis of T cell-mediated immunity. (wikipedia.org)
  • A subset of these B and T C cell populations become antigen-specific 'memory' cells to provide long-lived immunity to re-infection. (lehigh.edu)
  • B cells primarily function to make antibodies against antigens, act as antigen-presenting cells (APCs), and eventually develop into memory B cells to provide long-term immunity. (lumenlearning.com)
  • Relationship Between Cell-Mediated and Humoral ImmunityAntibody ProductionT-Dependent Antigens:â ¢ Antibody production requires assistance from T helper cells.â ¢ A macrophage cells ingest antigen and presents it to T H cell.â ¢ TH cell stimulates B cells â ¦ Howeverthe G-H loop of Define cell-mediated immunity and state what it is most effective against. (sem-web.org)
  • Cell-mediated immunity, also known as cellular immunity, is one of the two types of the adoptive immune system inside the body. (sem-web.org)
  • Cell Mediated Immunity is a cytotoxic T-cells & T-helper cells aided framework. (sem-web.org)
  • Cell-mediated immunity is defined as a beneficial host response characterized by an expanded population of specific T-cells, which, in the presence of antigens, produce cytokines locally. (sem-web.org)
  • Cell mediated immunity operates against intracellular pathogens. (sem-web.org)
  • Both local and cell-mediated immunity are likely to be important in protection. (sem-web.org)
  • Cellular immunity protects the body by: Cell-mediated immunity is directed primarily microbes that survive in phagocytes and microbes that infect non-phagocytic cells. (sem-web.org)
  • Cell-mediated immunity (CMI), determined by estimating the production of MIF from sensitized leucocytes, was followed for 12 months after natural rubella infection (twenty-two subjects) and after vaccination with the Cendehill strain of attenuated rubella virus vaccine (forty subjects). (sem-web.org)
  • Briefly compare humoral immunity with cell-mediated immunity. (sem-web.org)
  • Immune response to SARS-CoV-2 involves both cell-mediated immunity and antibody production. (sem-web.org)
  • In cell mediated immunity, be able to describe and distinguish the activities of cytotoxic T cells, helper T cells, suppressor T cells, and memory T cells. (wikipremed.com)
  • The clonal selection theory of adaptive immunity suggests that proliferation of a single lymphocyte should provide sufficient function for acute defense (effector cells), as well as the regenerative capacity to maintain the selected lineage (memory cells). (sciencemag.org)
  • The nature of vaccines (either humoral antibody immunity inducing or cell-mediated immunity inducing) depends on the location (extracellular or intracellular) and the expression of the antigens selected for incorporation. (jyi.org)
  • METHODS: Immunologic studies of non-antigen-specific functions of CD8 memory cells, their maturation in vivo, and their effects in a mouse asthma model, to test the hypothesis that CD8 memory is shaped by innate immunity in a way that can inhibit allergic disease. (ox.ac.uk)
  • RESULTS: We found that CD8 memory T-cell (CD8 Tm) populations bridge innate and adaptive immunity by responding to either antigen or cytokines alone. (ox.ac.uk)
  • Stimulation of innate or acquired immunity in the lung or gut causes expansion/maturation of CD8 Tm populations, which provide an early source of cytokines, enhance T(H)1 immunity, and inhibit allergic sensitization and airway inflammation/hyperresponsiveness in a non-antigen-specific fashion. (ox.ac.uk)
  • This novel type of memory enhances T(H)1 over T(H)2 immunity and prevents allergic sensitization after exposure to environmental antigens or infection. (ox.ac.uk)
  • Human Peritoneal Mesothelial Cells Display Phagocytic and Antigen-Presenting Functions to Contribute to Intraperitoneal Immunity. (umassmed.edu)
  • Chapter 8 T Cell-Mediated Immunity Once they have completed their development in the thymus , T cells enter the bloodstream and are carried by the circulation. (quadri-canvas.it)
  • Humoral immunity (also called the antibody-mediated system) is the aspect of immunity that is mediated by macromolecules (as opposed to cell-mediated immunity) found in extracellular fluids such as secreted antibodies, complement proteins and certain antimicrobial peptides. (quadri-canvas.it)
  • This response is largely carried out by B-cells but requires the help of CD4+ T-cells and thus in part depends on successful Cell-mediated Immunity. (quadri-canvas.it)
  • Vitamin E supplementation enhances cell-mediated immunity in healthy elderly subjects. (quadri-canvas.it)
  • T cell-mediated immunity, which is detected within 1-2 weeks after appearance of rash, and consists of both CD4 and CD8 effector and memory T cells, is essential for recovery from varicella. (quadri-canvas.it)
  • Do you think you have mastered the broad topic of Cell Mediated Immunity? (quadri-canvas.it)
  • It is cell-mediated immunity. (quadri-canvas.it)
  • Antonyms for cell-mediated immunity. (quadri-canvas.it)
  • Synonyms for T-cell-mediated immunity in Free Thesaurus. (quadri-canvas.it)
  • Cell-cell interactions in cell-mediated immunity - activation of NK cells. (quadri-canvas.it)
  • CELL-MEDIATED IMMUNITY: Cell interactions in specific immune responses : TEACHING OBJECTIVES Helper T cell-B cell interactions for antibody formation against hapten-conjugated proteins and complex proteins Thymus-independent antigens Properties and functions of cytokines. (quadri-canvas.it)
  • Cell-mediated definition is - relating to or being the part of immunity or the immune response that is mediated primarily by T cells. (quadri-canvas.it)
  • The activation of T-cells by a specific antigen is called cell-mediated immunity. (quadri-canvas.it)
  • T-cells originate in the thymus and provide cell-mediated immunity, when infected cells become inflamed. (christianhubert.com)
  • Antigen transfer in the thymus is the transmission of self-antigens between thymic Antigen presenting cells (APCs) which contributes to the establishment of T cell central tolerance. (wikipedia.org)
  • Unidirectional spreading of mTEC-derived TRAs onto additional APCs via antigen transfer increases the probability of encounter between potential autoreactive T cell and its corresponding TRA and therefore enhances processes of central tolerance. (wikipedia.org)
  • Despite relevance of antigen transfer, seminal study was published, showing mTECs to form fully established central tolerance without support of additional APCs. (wikipedia.org)
  • Experiments from this study reveal that clonal deletion of autoreactive CD4+ T cells, apart from CD8+ T cells, requires indirect presentation of TRAs by bone marrow (BM) derived APCs. (wikipedia.org)
  • When a pathogen is detected, these APCs will phagocytose the pathogen and digest it to form many different fragments of the antigen. (oercommons.org)
  • This is performed by antigen presenting cells (APCs). (harvard.edu)
  • It is during the early stages of the clonal selection process that immunoglobulin gene DNA rearrangements occur. (lehigh.edu)
  • During the several-week course of an immune response, B cells undergo a process of clonal expansion, somatic hypermutation of the immunoglobulin (Ig) genes and affinity-dependent selection. (meta.org)
  • The part of an immunoglobulin molecule that binds antigen specifically. (rxpgonline.com)
  • these cells carry immunoglobulin and class II MHC (major histocompatibility complex) antigens on their surfaces. (rxpgonline.com)
  • The major histocompatibility complex is a set of special proteins that combine with antigens from digested pathogens in macrophages and then display them on the outer surface membrane of the cell to produce and antigen-presenting cell. (abpischools.org.uk)
  • The response of the immune system to antigens found on the outside of pathogens or body cells. (abpischools.org.uk)
  • Ability of an organism to recognize and defend itself against specific pathogens or antigens. (scribd.com)
  • In contrast, cell-mediated immune responses are important in resisting diseases caused by pathogens that live within cells, such as viruses. (encyclopedia.com)
  • Thereby, B cells undergo a Darwinian selection process that favors clones that have evolved antibodies with the highest affinity to antigen derived from infectious pathogens. (aacrjournals.org)
  • Bioinformatics tools and algorithms like BLAST and FASTA are nowadays being adopted as a means to identify and detect common target antigens against Gram negative bacterial pathogens. (jyi.org)
  • The secondary immune response mediated by memory T cells is much faster and more effective at eliminating pathogens compared to the initial immune response. (aegisinteractive.com)
  • Although all immune responses are similar, each time the body is invaded by a different antigen, the exact response is specific to that antigen. (encyclopedia.com)
  • BCR-mediated internalization of Salmonella by B cells is superior over extracellular Ag extraction to induce rapid and specific humoral immune responses and efficiently combat infection. (jimmunol.org)
  • Clonal selection may explain why memory cells can initiate secondary immune responses more quickly than the primary immune response, due to increased binding affinity from clonal expansion. (lumenlearning.com)
  • Cytotoxic T cells destroy virus-infected cells in the cell-mediated immune response, and helper T cells play a part in activating both the antibody and the cell-mediated immune responses. (oercommons.org)
  • The basics of B and T cell clonal selection and the various cellular interactions involved in the humoral and cell-mediated immune responses are the foundation knowledge of immunology needed for proceeding further in a study of virology. (lehigh.edu)
  • The clonal selection hypothesis may explain why secondary immune responses are so effective at preventing reinfection by the same pathogen. (lumenlearning.com)
  • Effector cells: carry out immune responses that ultimately destroy or inactivate the antigens. (studymode.com)
  • Cell proliferation and differentiation in the central lymphoid organs (thymus and bone marrow) yield a repertoire of T- and B-cell clones that seed into peripheral lymphoid organs (spleen, lymph nodes and Mucosa-Associated Lymphoid Tissue, MALT), where humoral and cell-mediated antigen-specific immune responses occur. (elsevier.com)
  • Type-2-cell-mediated immune responses play critical roles in regulating host resistance against helminths and promoting tissue repair and metabolic homeostasis. (quadri-canvas.it)
  • Be familiar with the reticuloendothelial system and the phagocytic nature and mechanisms of antigen presentation by macrophages and dendritic cells. (wikipremed.com)
  • etc.Antigens Most are proteins or large polysaccharides from a foreign organism. (scribd.com)
  • For instance, individuals produce innumerable "self" antigens and are constantly exposed to harmless foreign antigens, such as food proteins, pollen, or dust components. (oercommons.org)
  • We show that a dividing T lymphocyte initially responding to a microbe exhibits unequal partitioning of proteins that mediate signaling, cell fate specification, and asymmetric cell division. (sciencemag.org)
  • This is a T cell-mediated immune response, also called delayed hypersensitivity, in which the body's immune system recognizes as foreign, and attacks, the complex of urushiol-derivatives with skin proteins. (quadri-canvas.it)
  • When a particular B-cell come into contact with an antigen which it fits, the B-cell swells and divides (through mitosis , or clonal selection)and the new activated B-cells (Plasma cells) secrete antibodies proteins that attack the invader. (christianhubert.com)
  • During cell-mediated responses, immune cells that can destroy infected host cells become active. (encyclopedia.com)
  • High-affinity Ab responses to T cell-dependent Ags typically require the generation of germinal centers (GCs), unique anatomic structures in peripheral lymphoid tissues enriched for B cells undergoing somatic hypermutation, Ig class switch recombination, and Ag-mediated selection and clonal expansion ( 3 ). (jimmunol.org)
  • There are two types of adaptive responses: the cell-mediated immune response , which is carried out by T cells, and the humoral immune response , which is controlled by activated B cells and antibodies. (oercommons.org)
  • Protective memory B cell responses are shaped through multiple mechanisms, including clonal selection of naïve B cells and affinity maturation. (sciencemag.org)
  • They observed that repeated immunization induced potent responses to the immunodominant PfCSP NANP repeat by the clonal selection of naïve and preexisting memory B cell precursors and was less influenced by affinity maturation. (sciencemag.org)
  • Computational modeling indicated that these responses are shaped by the complexity of the antigen, and these findings provide a new perspective on protective B cell responses. (sciencemag.org)
  • Affinity maturation, the clonal selection and expansion of antigen-activated B cells expressing somatically mutated antibody variants that develop during T cell-dependent germinal center reactions, is considered pivotal for efficient development of protective B cell memory responses to infection and vaccination. (sciencemag.org)
  • Here, we determined the relative impact of affinity maturation versus antigen-mediated clonal selection of naïve B cells to mount potent B cell memory responses in humans after repeated exposure to a complex pathogen, the malaria parasite Plasmodium falciparum (Pf). (sciencemag.org)
  • This germline component of antigen recognition may explain the unusually high precursor frequency, prevalence and immunodominance of T-cell responses specific for the A2/LLW epitope. (cdc.gov)
  • Strategically localized dendritic cells promote rapid T cell responses to lymph-borne particulate antigens. (naver.com)
  • Mice cured of tumors demonstrated CD4 + and CD8 + T-cell responses specific for CEA but also revealed the induction of high levels of T-cell responses to two other antigens (gp70 and p53) overexpressed in tumor, indicating the presence of a consequential antigen cascade. (aacrjournals.org)
  • A term used by allergists to describe IgE-mediated anaphylactic responses in humans, usually genetically determined. (rxpgonline.com)
  • mice also mounted significantly higher antibody responses to T-independent type 2 antigen. (frontiersin.org)
  • A model describing concurrent T-dependent and T-independent B cell responses in the context of DENV infection is proposed, which incorporates the selection of B cells using hypomutated IGHV segments and their potential role in poly/cross-reactivity. (beds.ac.uk)
  • sequencing of the TCR repertoire thus can highlight clonotypic diversity and the dynamics of antigen-dependent responses associated with disease, such as clonal expansion or selection 2,8,9 . (researchsquare.com)
  • They receive the final signal necessary for clonal selection from T H cells and cytokines. (encyclopedia.com)
  • Antigens are selected to form clones of themselves, both memory and effector. (lumenlearning.com)
  • During T cell differentiation, the naive T cell becomes a blast cell that proliferates by clonal expansion and differentiates into memory and effector T cells. (lumenlearning.com)
  • Clonal selection is thought to cause mutations of antigen-binding affinity in memory cells during clonal expansion so that memory cells have greatly increased antigen-binding affinity than the effector cells during the first response. (lumenlearning.com)
  • B-cell clonal expansion starts as an antigen-driven event and expands towards indolent and malignant B-cell proliferation. (hindawi.com)
  • This fundamental concept is called the clonal selection hypothesis. (aspeneducationgroup.com)
  • It was first suggested by Niels Jerne in 1955, and most clearly enunciated by Macfar-lane Burnet in 1957, as a hypothesis to explain how the immune system could respond to a large number and variety of antigens. (aspeneducationgroup.com)
  • FIGURE 1-7 The clonal selection hypothesis. (aspeneducationgroup.com)
  • These cells encounter the foreign invader and present the invader's antigens to a group of T cells called helper T cells (T H cells). (encyclopedia.com)
  • During GC colonization, B cells engage in long-lasting interactions with T follicular helper (Tfh) cells, a process that depends on antigen uptake and antigen presentation to the Tfh cells. (rupress.org)
  • Development of an effective humoral immune response is mediated by two actions of the BCR: transmembrane signaling through BCR complexes to induce B cell differentiation and Ag internalization for processing followed by MHC class II-mediated presentation to acquire T cell help. (jimmunol.org)
  • Studies on MHC-mediated presentation of BCR-specific Ags are mainly performed with soluble Ags or with pre-cross-linked anti-BCR Abs. (jimmunol.org)
  • In 1974 the role of MHC in antigen presentation was demonstrated by Rolf Zinkernagel and Peter C. Doherty. (news-medical.net)
  • How long-lasting T-B interactions and B cell clonal expansion are regulated by antigen presentation remains unclear. (rupress.org)
  • T and B cells are able to respond to nearly all of the world's vast variety of antigens upon presentation. (lumenlearning.com)
  • These processes are mediated especially by unique subset of stromal cells called Medullary thymic epithelial cells (mTECs) via presentation of Tissue restricted antigens (TRAs) that represent self tissues from almost all parts of the body. (wikipedia.org)
  • Furthermore, antigen transfer enables TRA processing and presentation by different cellular microenvironments. (wikipedia.org)
  • Requirement of indirect presentation of some mTEC-derived TRAs in the case of recessive tolerance was perceived also by additional studies which both firstly demonstrated antigen transfer as an instrument that enables this process. (wikipedia.org)
  • Indispensability of DCs for the establishment of central tolerance was further verified by recent analysis, which revealed that DCs mediate both recessive and dominant tolerance, with preference for the latter, via presentation of more common TRAs. (wikipedia.org)
  • Antigen Presentation" is a descriptor in the National Library of Medicine's controlled vocabulary thesaurus, MeSH (Medical Subject Headings) . (harvard.edu)
  • Antigen processing consists of ingestion and partial digestion of the antigen by the APC, followed by presentation of fragments on the cell surface. (harvard.edu)
  • This graph shows the total number of publications written about "Antigen Presentation" by people in Harvard Catalyst Profiles by year, and whether "Antigen Presentation" was a major or minor topic of these publication. (harvard.edu)
  • Below are the most recent publications written about "Antigen Presentation" by people in Profiles. (harvard.edu)
  • Polyglutamine-Related Aggregates Can Serve as a Potent Antigen Source for Cross-Presentation by Dendritic Cells. (harvard.edu)
  • Latency reversal agents modulate HIV antigen processing and presentation to CD8 T cells. (harvard.edu)
  • Cherukuri A, Cheng PC, Pierce SK (2001a) The role of the CD19/CD21 complex in B-cell processing and presentation of complement-tagged antigens. (springer.com)
  • In addition, staff provide training and consultation in flow cytometry techniques, protocol design, reagent selection, and data analysis and presentation. (cancer.gov)
  • Indeed, as mTECs represent exclusive donors of TRAs, experiments with first antigen transfer mouse models discovered thymic dendritic cells (DCs) to be so far the only known TRAs acceptors involved in antigen transfer. (wikipedia.org)
  • Furthermore, bone marrow (BM) chimeras between Tg and WT mice reveal that CD1d-expressing BM-derived dendritic cells, but not thymic epithelial cells, mediate the efficient negative selection of NKT cells. (rupress.org)
  • CD8 Tm populations partially subvert the clonal selection process by activating their neighbors through induction of dendritic cell IL-12. (ox.ac.uk)
  • They rise extrathymically, and were shown to present self antigens, especially blood-borne antigens, in the thymus, which they acquire in the periphery. (wikipedia.org)
  • The last abundant subset of thymic DCs is represented by B220+ plasmacytoid DCs (pDCs) which also rise extrathymically and transfer peripheral antigens from the periphery to the thymus to mediate selection processes. (wikipedia.org)
  • This suggested that the thymus was a crucial source of cells that mediate phenomena such as rejection, but his experiments were not universally accepted. (vetscite.org)
  • B cells undergo clonal selection and develop similarly to T cells with some notable differences. (lumenlearning.com)
  • The summation of multiple affinities, for example when a polyvalent antibody binds to a polyvalent antigen. (rxpgonline.com)
  • RAG genes mediate V(D)J recombination, and AID drives somatic hypermutation and class-switch recombination of Ig genes. (aacrjournals.org)
  • Such iterative mutation and selection are likely the result of the ability of HIV-1 to escape the antibodies generated by initial rounds of somatic hypermutation due to the exceptionally high mutation rate of the HIV-1 genome. (evmedreview.com)
  • Most of these will never encounter a matching 5) foreign antigen, but those that do are activated and produce 6) many clones of themselves. (lumenlearning.com)
  • This primary immune response to a foreign antigen takes a week to develop, during which time infecting microbes can replicate within the host body. (jyi.org)
  • In this sense, one of the immune system main properties is to distinguish "self" from "no self or foreign" ( Antigen A substance that when introduced into the body (non-self antigens as chemicals, toxins, bacteria, or viruses), stimulates the immune system to produce antibodies." class="glossaryLink ">antigen ), and to eliminate the later through the induction of a variety of mechanisms. (necropsymanual.net)
  • Iterative cycles of cell division and SHM followed by selection by Tfh cells in the GC results in a progressive increase in serum antibody affinity ( Kepler and Perelson, 1993 ), a process known as antibody affinity maturation ( Eisen and Siskind, 1964 ). (rupress.org)
  • Repeated antigen exposure promotes affinity maturation but each time also recruits antigen-reactive naïve B cells into the response. (sciencemag.org)
  • A schematic to illustrate common mechanisms of normal B-cell affinity maturation (top) and clonal evolution toward leukemia and lymphoma (bottom). (aacrjournals.org)
  • Serum containing antibodies to a specific antigen(s). (scribd.com)
  • After an antigen is cleared from the body, immunological memory allows an antigen to be recognized and removed more quickly if encountered again. (encyclopedia.com)
  • Clonal selection is an important immunological process that determines which B and T , types of white blood cells, will be produced in large quantities. (aegisinteractive.com)
  • In general terms the immune system is the response of the hosts to an Antigen A substance that when introduced into the body (non-self antigens as chemicals, toxins, bacteria, or viruses), stimulates the immune system to produce antibodies." class="glossaryLink ">antigen (Ag), which conversely, to be considered such, it must be capable of stimulating an immunological response. (necropsymanual.net)
  • The only organisms with totally matching antigens are identical twins and clones. (abpischools.org.uk)
  • We find that intercellular adhesion molecule 1 (ICAM-1) and ICAM-2 on B cells are essential for long-lasting cognate Tfh-B cell interactions and efficient selection of low-affinity B cell clones for proliferative clonal expansion. (rupress.org)
  • How B cell clones bearing BCRs of various affinities are selected for clonal expansion and GC colonization remains unclear. (rupress.org)
  • This mass production is termed "clonal expansion," in which daughter cells proliferate into several generations of clones of the original parent cells. (lumenlearning.com)
  • Multiple rounds of mutation and selection favor the outgrowth of individual clones based on competitive fitness and drive clonal evolution toward overt leukemia or lymphoma. (aacrjournals.org)
  • Distributions of clonal sizes were mostly identical for young and elderly individuals and an age-related increase in clonal sizes was seen only for the largest clones. (aegisinteractive.com)
  • It is this process of clonal selection and the ultimate perpetuation of these antigen-specific memory cells that protects against a secondary infection. (jyi.org)
  • The stringent process of clonal selection in the central lymphoid organs implies deletion of inappropriate cells via apoptosis. (elsevier.com)
  • Thus, our data suggest that NKT cells developmentally undergo negative selection when engaged by high-avidity antigen or abundant self-antigen. (rupress.org)
  • Thymocytes that interact too strongly with the self-antigen receive an signal that leads to cell death. (aegisinteractive.com)
  • After antigenic stimulation, there is activation and expansion of these antigen-specific cells. (jyi.org)
  • A measure of the binding constant of a single antigen combining site with a monovalent antigenic determinant. (rxpgonline.com)
  • Immediate hypersensitivity response to antigenic challenge, mediated by IgE and mast cells. (rxpgonline.com)
  • The altered state of immunologic responsiveness resulting from initial contact with antigen, which enables the individual to produce antibodies more rapidly and in greater quantity in response to secondary antigenic stimulus. (umassmed.edu)
  • They are difficult to study because they undergo rapid clonal antigenic variation in vitro, which precludes the derivation of phenotypically homogeneous cultures. (pnas.org)
  • When activated, a B lymphocyte's secreted antibodies enter the blood and other body fluids, where the bind the antigen and help destroy it. (encyclopedia.com)
  • Recognize and bind to antigens b. (coursehero.com)
  • They spot peptide fragments of antigens on the surface of body cells and are able to bring the peptide to the cell surface where the T-cell can bind to it, through a molecule known as a major histocompatibility complex (MHC) protein. (christianhubert.com)
  • In the bone marrow, central tolerance of B cells is produced through negative selection. (lumenlearning.com)
  • Cytokine like CXCL13 contribute to B-cell homing in intraportal lymphoid aggregates, in which B-cell clonal selection may arise. (hindawi.com)
  • In the secondary lymphoid organs there is a similar process called Peripheral Tolerance or Clonal Anergy. (aegisinteractive.com)
  • The next major advance was in the 1940s, when Linus Pauling confirmed the lock-and-key theory proposed by Ehrlich by showing that the interactions between antibodies and antigens depended more on their shape than their chemical composition. (news-medical.net)
  • Jerne, Talmage and Burnet in the late 1950's found the clonal selection theory. (news-medical.net)
  • From 1962 he focused on immune reactions, demonstrating that antigens are not present in antibody-producing cells, in support of Burnet's clonal selection theory. (wikipedia.org)
  • In immunology he provided evidence that refuted the template theory of antibody formation and performed elegant experiments to prove Burnet's Clonal Selection Theory. (science.org.au)
  • Antigen fragments will then be transported to the surface of the APC, where they will serve as an indicator to other immune cells. (oercommons.org)
  • The innate immune system contains cells that detect potentially harmful antigens, and then inform the adaptive immune response about the presence of these antigens. (oercommons.org)
  • An antigen-presenting cell (APC) is an immune cell that detects, engulfs, and informs the adaptive immune response about an infection. (oercommons.org)
  • Two processes of central tolerance take place in thymic medulla, namely clonal deletion (recessive tolerance) and T Regulatory cells selection (dominant tolerance) which force autoreactive T cells to apoptosis or skew them into suppressor T regulatory cells (TRegs), respectively, in order to protect body against manifestations of autoimmunity. (wikipedia.org)
  • Similar rearrangements occur for the light-chain V region but with only two segments involved: V and J. When the B cell fails in any step of the maturation process, it will die by apoptosis, here called clonal deletion. (lumenlearning.com)
  • The body does not usually start an immune response against its own antigens because cells that recognize self-antigens are deleted or inactivated. (encyclopedia.com)
  • This process is called clonal selection because only the T H cells that recognize the foreign invader are selected to reproduce. (encyclopedia.com)
  • For conventional T cells, a key factor in determining whether a DP thymocyte undergoes positive or negative selection is the avidity and affinity of the TCR-ligand interaction ( 30 - 32 ). (rupress.org)
  • In order to understand this technique you need a basic understanding of the immune response and antibody-antigen interaction. (edu.au)
  • Asymmetric segregation of determinants appears to be coordinated by prolonged interaction between the T cell and its antigen-presenting cell before division. (sciencemag.org)
  • A functional term for an antibody molecule capable of blocking the interaction of antigen with other antibodies or with cells. (rxpgonline.com)
  • Although the size and diversity of the lymphocyte repertoire make it likely that there is an antigen, a specific lymphocyte for any given pathogen, the frequency of these cells can be extremely low and normally will not be sufficient to protect the host against a primary infection. (jyi.org)
  • Hence, the goal of vaccination is to enhance the number of antigen-specific B and T cells against a given pathogen. (jyi.org)
  • If these B cells have high affinity for binding to self-antigens, they will die by clonal deletion or another pathway such as anergy. (lumenlearning.com)
  • on the other hand, clonal deletion and anergy provide a detrimental escape to immune recognition of malignant cells. (elsevier.com)
  • All these thymic DC subsets were shown to participate in antigen transfer. (wikipedia.org)
  • Here, we report that the addition of agonist glycolipid α-galactosylceramide (α-GalCer) to a fetal thymic organ culture (FTOC) induces a dose-dependent disappearance of NKT cells, suggesting that NKT cells are susceptible to negative selection. (rupress.org)
  • First, the positive selection of NKT cells is mediated by CD4 + CD8 + double-positive (DP) thymocytes ( 18 , 19 ), while thymic epithelial cells are responsible for positive selection of conventional T cells. (rupress.org)
  • On the other hand, the cell-mediated system responds to body cells that have changed in some way - for example cells infected by viruses, or cells such as cancer cells that have a mutation. (abpischools.org.uk)
  • Through genetic mutation and recombination events, activated B cells can continuously adapt to antigen. (aacrjournals.org)
  • Multiple rounds of mutation and selection lead to expression of high-affinity antibodies (top). (aacrjournals.org)