HLA‐DRβIII and HLA‐DP induce comparable proliferation in primary mixed lymphocyte culture

Abstract
To study the stimulatory capacity of HLA-DR.beta.III in the mixed lymphocyte culture (MLC) assay, an MLC matrix between 13 Dw18 homozygous typing cells (HTCs) was analysed. Six of these HTCs were positive for the HLApDR.beta.III allele LBV-Q1 as defined by T cell clones. Seven HTCs were positive for LB-Q4. The MLC responses between Dw18 HTCs, matched for LB-Q, were significantly lower than the responses between the mismatched combinations. Considering the fact that HLC-DP can induce proliferation in MLC, we then analyzed the DP matched and mismatched combinations separately. The influence of HLA-DR.beta.III mismatches was in our experiments comparable to the influence of mismatches for HLA-DP. Surprisingly, 15 out of 22 DR.beta.III and DP matched combinations still showed positive MLC reactions.