HLA-B16 ANTIGENS - SEQUENCE OF THE ST-16 ANTIGEN, FURTHER DEFINITION OF 2 B38 SUBTYPES AND EVIDENCE FOR CONVERGENT EVOLUTION OF B-ASTERISK-3902

The ST-16 antigenic specificity of the HLA-B locus is defined as a B39 variant of Mexican-Americans. Nucleotide sequencing of cDNA shows the ST-16 allele (B3905) differs from B*39011 by a single substitution t hat substitutes tyrosine for aspartic acid at position 74 of the matur e class I heavy chain. The complete coding region sequence for the com mon caucasoid allele encoding the B38 antigen has been determined. Thi s B3801 allele differs from B*3802 at two nucleotide substitutions wi thin the Bw4 sequence motif. B3801 and B*3802 may have been derived i ndependently from B39011 by conversion events with B alleles donating distinctive Bw4 motifs. A novel allele B39022 derived from a Colombi an Indian differs from the B39021 allele of Japanese origin at two wi dely separated silent substitutions. Comparison of sequences for the k nown B16 alleles suggest that B39021 and B*39022 were independently d erived by recombination from B39013 and B*39011 respectively.