A “new” supertypic HLA‐DP related determinant detected by Primed Lymphocyte Typing (PLT)

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Abstract
Primed Lymphocyte Typing (PLT) with local (CDP) and the 9th International Histocompatibility Workshop reagents (GNN) revealed “cross‐reactions” between HLA‐DPw6 and the GNN2B but not other DPw2 PLT‐cells (GNN2A. CDP2A. CDP2B). We raised and bulk‐expanded a well discriminating PLT‐reagent (the JET‐reagent) from an HLA‐DR identical, DP. GNN2A, CDP2A, CDP2B compa. tible and GNN2B incompatible responder/stimulator combination. The JET‐reagent defined a “new” determinant, JET, which was present in 11% of Danes. The JET determinant was associated with DPw2, w6, and DP‐blank: 66% of DPw6 and DP‐blank and 20% of DPw2‐positive individuals were JET‐positive. All JET‐positive individuals belonged to this group, and six of these had two DP‐antigens. JET segregated with DP‐blank in three and with DPw6 in two informative families. In an HLA‐DR/DPw6 recombinant family, JET segregated with DPw6 in the recombinant haplotype. The JET PLT‐responses against all of six different JET‐positive stimulators including the specific stimulator were strongly inhibited by the monoclonal antibody (MoAb) Tü39, which preferentially reacts with DP‐molecules, but not by other HLA‐specific MoAbs. The results indicate that JET is cither a “new” supertypic DP‐related specificity or a determinant, which shares epitopes with DP, of a “new” locus and in linkage disequilibrium with DP.