Expression of an unusual Bw4 epitope by a subtype of HLA-B8 [B*0802].

The primary structure of a variant HLA-B8 antigen has been determined by cDNA cloning and sequencing. The variant, B0802 differs, from the common B0801 subtype at positions 77-83 of the alpha 1 helix that determine the Bw4 and Bw6 public epitopes. Whereas B0801 has the common Bw6 motif, B0802 has the Bw4 motif found in B13 and B44 allotypes. Serological analysis of B cell lines expressing B0802 and of a B0802 transfectant made with the HLA-A,B negative cell line 721.221 shows that B*0802 reacts with Bw4-specific antibodies, but at a level much lower than expected for Bw4 positive HLA-B allotypes.