SEROLOGICAL AND MOLECULAR-IDENTIFICATION OF AN HLA-B8 VARIANT, HLA-B8JON(B-ASTERISK-0802)

The serological and molecular characteristics of the first HLA-B8 vari ant (B8Jon), located on a haplotype bearing HLA-A1, -B8Jon, -Cw07, DR B10301, DQA1*05, DQB1*0201, BfS, C4AQ0, C4B1 and the microsatellite a lleles D6S265-3, 258-11, 105-8, 299-1 and 202-2 are identified and des cribed. This new HLA-B antigen was distinguished from the usual B8 by its lack of reactivity with Bw6 and most Bw4 antisera, together with i ts failure to react with most antisera cross-reactive with HLA-B8. B8J on gives a 'weaker' response than HLA-B8 in titration studies with B8 antisera. It cannot be differentiated from the usual B8 by one-dimensi onal iso-electric focusing. Time course studies, absorption analyses a nd serological tests on 17 Bw4 antibodies suggest that B8Jon possesses an unusually 'weak' Bw4 epitope. Studies on the Bw4 sequence motif by PCR, using sequence-specific primers, indicate that B8Jon has a Bw4 s equence in common with other HLA-B alleles, including B4402-B*4405, r ather than the Bw6 motif found on the familiar HLA-B8 molecule.