Oligonucleotide genotyping shows that alleles at the HLA-DRβIII locus of the DRw52 supertypic group segregate independently of known DR or Dw specificities

Using locus- and allele-specific oligonucleotide probes, we have studied the polymorphism of the HLA-DRβIII locus within the haplotypes of the DRw52 supertypic group. DNA from a number of homozygous typing cells typed for both Dw and DR was used. The DRβIII polymorphisms, DRw52a and DRw52b, do not segregate with Dw typing, or with DR typing, indicating that the determinants responsible for Dw-defined T -cell response and for DR haplotypic recognition are not encoded by the DRβIII locus. Hence, we can conclude that these DR specificities are encoded by the other functional DR locus, DRβI, while the DRβIII locus encodes only the supertypic product.