HLA-linked B cell alloantigens of a new segregant series: Population and family studies of the SB antigens

In order to define new human histocompatibility antigens, we have generated primed lymphocytes using responder and stimulator cells matched for all recognized HLA-linked histocompatibility antigens (A,B,C,D,DR,MB). Many such primed lymphocytes give highly discriminatory proliferative responses specific for antigens which differ between HLA-A,B,C,D,DR, and MB matched restimulating cells. Five distinct antigens have been defined which appear to be part of a single segregant series (designated “SB”). Studies in a DR/GLO recombinant family indicate that the antigens are coded by an HLA-linked gene telomeric to GLO. Family studies of 57 HLA haplotypes provide an estimate of genotype frequency which is 12% or less for four of the SB alleles but approximately 50% for the most common (SB4, which may be a “public” determinant); approximately 25% of haplotypes are black. Population studies of one of the SB antigens (SB1) suggest that it is in linkage disequilibrium with A1, B8, and DRw3. These results, together with results of other studies [1], indicate that the SB antigens are part of a highly polymorphic new segregant series of B cell alloantigens encoded by a gene that maps between HLA-B and GLO.