The new HLA-DRw6- and 8- associated HLA-Dw HAG specificity defined by homozygous typing cell 9W 1802

Abstract

Intrafamilial primary mixed lymphocyte culture (MLC) typing established that an HLA‐A, B, C homozygous, DP heterozygous donor HAG was homozygous for HLA‐Dw and behaved as a homozygous typing cell (HTC). Both haplotypes of the HTC were HLA‐DR identical, but could not be assigned a clear DR specificity, giving reactions with sera containing antibodies against DRw6, DRw8 and TA10. MLC checkerboard studies failed to assign the HTC HAG specificity to any established or provisional cluster, suggesting that it defined a new Dw specificity. Primed lymphocyte typing (PLT) clones derived from intra‐familial priming against either HAG haplotype displayed heterogeneous reactivity patterns. One clone was restimulated only by family members and unrelated donors positive for Dw HAG. Other clones were restimulated by determinants associated with either Dw8 or Dw6. Blocking of stimulation with monoclonal antibodies against different class II molecules suggested that while stimulatory determinants associated with Dw HAG and Dw8 were classifiable as HLA‐D related, those associated with Dw6 were of a DP‐like nature.