A monoclonal antibody which detects a polymorphic la antigenic determinant reacts with purifiedβpolypeptide chain
✍ Scribed by W. Robert McMaster
- Book ID
- 104741193
- Publisher
- Springer-Verlag
- Year
- 1981
- Tongue
- English
- Weight
- 233 KB
- Volume
- 13
- Category
- Article
- ISSN
- 0093-7711
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✦ Synopsis
The Ia antigens are a group of cell-surface glycoproteins that have a high degree of polymorphism and are coded for by the major histocompatibility complex (M/511er 1976, Klein 1979). These antigens have been identified in several species and are composed of two glycosylated polypeptides which are strongly associated by noncovalent forces to form a two-chain structure (Cullen et al. 1976, Silver et al. 1976, Snary et al. 1976, Springer et al. 1977, McMaster and Williams 1979a). The larger chain, called e, and the smaller chain, called fi, have apparent molecular weights of 32 000 to 36 000 and 25 000 to 30 000, respectively. In the mouse there are two sets of Ia antigens with this structure, with antigenic polymorphisms mapping to the I-A and I-E/C subregions of the H-2 complex (Cullen et al. 1976). Similarly, there are at least two independent Ia antigens in the rat (Shinohara et al. 1978, Blankenhorn et al. 1980, T. Fukumoto, W. R. McMaster and A. F. Williams, submitted for publication) and probably two Ia (HLA-DR) antigens in the human (Tosi et al. 1978, Lampson andLevy 1980).
Recent studies, in which comparisons were made between mouse Ia antigens coded for by the I-A subregion and isolated from different haplotypes, showed that both the c~ and fl chains exhibited structural differences (Silver and Russel 1979, Cook et al. 1979). The Ia polymorphic specificities are detected by antibody, therefore, these results may indicate that both the ~ and fi chains contribute to the alloantigenicity of Ia antigens. Monoclonal antibodies have been produced against rat Ia antigens (reviewed in McMaster and Williams 1979b). One of these monoclonal antibodies, MRC OX 6, detects an Ia antigenic determinant that is common in all rat strains tested and cross-reacts in mice with a polymorphic Ia antigenic determinant coded for by the I-A subregion. This communication demonstrates that MRC OX 6 antibody reacts with the fi chain of purified rat Ia antigen.