histocompatibility antigen
- histocompatibility antigen
-
A set of plasmalemmal glycoproteins that are crucial for
T-cell recognition of antigens. Particularly the
HLA system in humans and the H2 system in mice. There are two classes of
histocompatibility antigens: (1) Class I;
histocompatibility antigens composed of two glycosylated subunits,
a heavy chain of 44 kD and b 2-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 recognized in conjunction with the foreign
cell surface antigens (MHC restriction).
(2) Class II antigens; heterodimeric
histocompatibility antigens composed of
a (32 kD) and b (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).
Dictionary of molecular biology.
2004.
Look at other dictionaries:
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