Polymorphism of human B-cell alloantigens: evidence for three loci within the HLA system.

Abstract

The B-cell alloantigens of an HLA-DR3-homozygous, MB2-homozygous, MT2-positive lymphoblastoid cell line were studied by 2-dimensional gel electrophoresis. Analysis of gel patterns suggested assignment of the HLA-DR3 determinant to the larger (35,000-dalton) subunit (.alpha.) of the B-cell alloantigen. MB2 was either a determinant on the small (27,000-dalton) subunit (.beta.) or a crossreactive determinant(s) on the HLA-DR3 .alpha.-subunit and an additional .alpha.-subunit. MT2 was a determinant on Ia antigen-like molecules distinct from those carrying the MB and HLA-DR determinants. Results are consistent with the existence in the major histocompatibility complex of at least 3 loci encoding B-cell alloantigens.