SEQUENCE POLYMORPHISM OF HLA-DP b CHAINS

Polymorphic residues in the N terminal domains of major histocompatibility complex class I and to a lesser extent classII c~chains influence interactions of the molecules with peptide antigens and T-cell receptors, and are the basis for HLA restriction of effector to target cell interactions.While first domains of several HLA-DRB1,DRB4,DQA1, andDQB1 alleleshavebeen sequenced and analyzed, much less is known about sequence polymorphism of the HLA-DPA1 and DPB1 genes.In addition, polymorphismdetectedat the DP locus by cellular assays is much lower than that for DR and DQ.We undertook DNA sequences analysis of HLA class II cDNAs from HLA homozygous cell lines to define the polymorphisms within allelic groups more precisely. Full-length cDNA clones encoding DPB1 chains were obtained from four cell lines that were analyzed for the Tenth International HLA Workshop.