| antigens, CD8 | <immunology> 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 major histocompatibility complex class I-restricted interactions. (12 Dec 1998) |
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| antigens, CD80 | <immunology> The natural ligand for the T-cell antigen CD28 (antigens, CD28) mediating t-cell and B-cell adhesion. Cd80 is expressed on activated B-cells and gamma-interferon-stimulated monocytes. The binding of CD80 to CD28 and ctla-4 provides a co-stimulatory signal to T-cells and leads to greatly upregulated lymphokine production. (12 Dec 1998) |
| antigens, CD95 | <immunology> Differentiation antigens expressed on a variety of cell lines including myeloid and lymphoblastoid cell lines. Their primary role is to regulate peripheral immune responses, which is achieved by triggering apoptosis. (12 Dec 1998) |
| antigens, differentiation | 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. (12 Dec 1998) |
| antigens, differentiation, b-lymphocyte | Membrane antigens associated with maturation stages of B-lymphocytes, often expressed in tumours of B-cell origin. (12 Dec 1998) |
| antigens, differentiation, myelomonocytic | Surface antigens expressed on myeloid cells of the granulocyte-monocyte-histiocyte series during differentiation. Analysis of their reactivity in normal and malignant myelomonocytic cells is useful in identifying and classifying human leukaemias and lymphomas. (12 Dec 1998) |
| antigens, differentiation, t-lymphocyte | Antigens expressed on the cell membrane of T-lymphocytes during differentiation, activation, and normal and neoplastic transformation. Their phenotypic characterization is important in differential diagnosis and studies of thymic ontogeny and T-cell function. (12 Dec 1998) |
| antigens, fungal | Substances of fungal origin that have antigenic activity. (12 Dec 1998) |
| antigens, helminth | Any part or derivative of a helminth that elicits an immune reaction. The most commonly seen helminth antigens are those of the schistosomes. (12 Dec 1998) |
| antigens, heterophile | Antigens stimulating the formation of, or combining with heterophile antibodies. They are cross-reacting antigens found in phylogenetically unrelated species. (12 Dec 1998) |
| antigens, human platelet | Human alloantigens expressed only on platelets, specifically on platelet membrane glycoproteins. These platelet-specific antigens are immunogenic and can result in pathological reactions to transfusion therapy. (12 Dec 1998) |
| antigens, ly | A group of lymphocyte surface antigens differentially located on subpopulations of mouse lymphocytes. This localization has been useful in distinguishing different functional subpopulations of lymphocytes. For example, cytotoxic T-cells bear primarily lyt-23 on their surface and not lyt-1, whereas helper cells bear lyt-1 and not lyt-23. (12 Dec 1998) |
| antigens, neoplasm | Proteins, glycoprotein, or lipoprotein moieties on surfaces of tumour cells that are usually identified by monoclonal antibodies. Many of these are of either embryonic or viral origin. (12 Dec 1998) |
| antigens, polyomavirus transforming | 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. (12 Dec 1998) |
| antigens, protozoan | Any part or derivative of any protozoan that elicits immunity; malaria (plasmodium) and trypanosome antigens are presently the most frequently encountered. (12 Dec 1998) |
| heterogenetic antigen | An antigen which is possessed by a variety of different phylogenetically unrelated species; e.g., the various organ-or tissue-specific antigen's, the alpha-and beta-crystalline protein of the lens of the eye, and Forssman antigen. Synonym: heterophil antigen. (05 Mar 2000) |
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| heterogenic enterobacterial antigen | Cross reacting antigen (epitope), a common antigen that occurs in 2 or more different molecules/organisms. Synonym: heterogenic enterobacterial antigen. (05 Mar 2000) |
| heterophil antigen | An antigen which is possessed by a variety of different phylogenetically unrelated species; e.g., the various organ-or tissue-specific antigen's, the alpha-and beta-crystalline protein of the lens of the eye, and Forssman antigen. Synonym: heterophil antigen. (05 Mar 2000) |
| heterophile antigen | An antigen or antigenic determinant which is found in different tissues in more than one species. (05 Mar 2000) |
| Xg antigen | xg blood group |
| histocompatibility antigen | <immunology> A set of plasmalemmal glycoproteins on the surface of all nucleated cells that are crucial for T-cell recognition of antigens. Particularly the HLA system in humans and the H2 system in mice. They are the major antigens responsible for tissue recognition. For this reason, they are of prime importance in determining compatible organ donors for a specific transplantation procedure. Each person has unique HLA antigens. Some HLA antigens have been identified to be correlated with the presence of certain autoimmune diseases. One of these is the HLA-B27 site. Approximately 85% of patients with ankylosing spondylitis and Reiter's syndrome will have the HLA-B27 antigen present on the leukocytes. There are two classes of histocompatibility antigens: 1. Class I, histocompatibility antigens composed of two glycosylated subunits, a heavy chain of 44 kD and beta2 microglobulin (12 kD). The heavy chain may be coded by K, D or L genes of mouse H2 and A, B or C genes of human HLA complex. Class I antigens are important in T-cell killing and are recognised in conjunction with the foreign cell surface antigens MHC restriction). 2. Class II antigens, heterodimeric histocompatibility antigens composed of alpha (32 kD) and beta (28 kD) chains. Found mostly on B lymphocytes, macrophages and accessory cells. The response of T helper cells requires that the foreign antigen is presented in conjunction with the appropriate Class II antigens. (Murine H2 Ia antigens and human HLA DR antigens are Class II). (14 Oct 1997) |
| HLA-a1 antigen | <immunology> Human histocompatibility (HLA) surface antigen encoded by the a locus on chromosome 6. Individuals bearing this allele are more susceptible to hodgkin's disease. HLA-a1 is in linkage disequilibrium with HLA-b8 and HLA-dr3. (12 Dec 1998) |
| HLA-a2 antigen | <immunology> Human histocompatibility (HLA) surface antigen encoded by the a locus on chromosome 6. The HLA-a2 antigen is associated with recognition of the influenza a virus. (12 Dec 1998) |
| HLA-a3 antigen | <immunology> Human histocompatibility (HLA) surface antigen encoded by the a locus on chromosome 6. The allele occurs with increased frequency in individuals with idiopathic haemochromatosis. HLA-a3 is in linkage disequilibrium with HLA-b7 and HLA-dr2. (12 Dec 1998) |
| HLA-b27 antigen | <immunology> Human histocompatibility (HLA) surface antigen encoded by the b locus on chromosome 6. It is strongly associated with acute anterior uveitis, ankylosing spondylitis, and reiter's disease. Increased frequency of antigen in: ankylosing spondylitis (90%), Reiter syndrome (90%), enteropathic arthritis (75%), psoriatic arthritis (60%) normal frequency: white: 8%, black: 4% (12 Dec 1998) |
| HLA-b35 antigen | <immunology> Human histocompatibility (HLA) surface antigen encoded by the b locus on chromosome 6. It is weakly associated with a number of diseases. (12 Dec 1998) |
| HLA-b7 antigen | <immunology> Human histocompatibility (HLA) surface antigen encoded by the b locus on chromosome 6. There is a weak association between the presence of the HLA-b7 antigen and the diseases of narcolepsy and idiopathic haemochromatosis. HLA-b7 is in linkage disequilibrium with HLA-a3 and HLA-dr2. (12 Dec 1998) |
| HLA-b8 antigen | <immunology> Human histocompatibility (HLA) surface antigen encoded by the b locus on chromosome 6. It is in linkage disequilibrium with HLA-a1 and HLA-dr3. This explains the fact that though HLA-b8 was originally associated with several diseases, including coeliac disease, dermatitis herpetiformis, and myasthenia gravis, their association with HLA-dr3 is now considered more significant. (12 Dec 1998) |
| HLA-dr1 antigen | <immunology> Human immune-response, d-related antigen encoded by the d locus on chromosome 6 and found on lymphoid cells. (12 Dec 1998) |
| HLA-dr2 antigen | <immunology> Human immune-response, d-related antigen encoded by the d locus on chromosome 6 and found on lymphoid cells. It is in linkage disequilibrium with HLA-a3 and HLA-b7 and is strongly associated with goodpasture syndrome, multiple sclerosis, and narcolepsy. (12 Dec 1998) |