Two Alpha Chains and Three Beta Chains of Human Ia Antigens

Abstract

Human Ia antigens, structural and serologic analogues of murine Ia antigens, are composed of two polypeptide chains, α (34,000 MW) and β (28,000 MW). Like their murine counterparts, these polymorphic chains transiently associate with a third, invariant chain, Ii (31,000 MW) (1). These readily apparent similarities with the mouse raise questions about the genetic organization of the HLA-D region which codes for human Ia antigens. Its murine analog, the I region in the H-2 complex, is known to contain at least five genes whose products have been characterized either biochemically or serologically. In particular, two distinct populations of murine Ia antigens, I-A and I-E/C, have been analyzed and shown to be coded by two separate I region genes (2). In the past, studies based on family data and serology using conventional alloantisera indicated a considerable molecular diversity of the human Ia antigens. Development of hybridoma technology (3) and monoclonal anti-la antibodies provided specific reagents with which to try to isolate various species of human Ia antigens.KeywordsAlpha ChainBeta ChainInvariant ChainHomozygous Cell LineHuman Genetic Mutant Cell RepositoryThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.