Interspecies exchange of β 2-microglobulin and associated MHC and differentiation antigens

Abstract

Radiolabeled human β₂-microglobulin (β₂m) can bind to mouse histocompatibility (H-2) antigens on the cell surface or to partially purified H-2 antigens in solution. The complexes containing human β₂m and H-2 antigens from C3H (H-2^k) mice could be immunoprecipitated specifically with alloantisera, rabbit anti-H-2 xenoantisera, and with monoclonal H-2-specific antibodies. Specific association with H-2 antigens was also observed with other haplotypes. The only exception was B10.D2 (H-2 ^d ) from which complexes containing human β₂M could only be precipitated with anti-H-2 xenosera. Thus radiolabeled human β₂M can be used as a specific label for mouse H-2 antigens in precipitation and radioimmunoassays. The application of this finding extends to major histocompatibility complex antigens of other species, and to differentiation antigens with primary association with β₂m.