A supertypic HLA-DP specificity defined by two human-human hybridoma antibodies (TrB50; TrE11).

We here report two human-human hybridoma antibodies: TrB50 (IgG) and TrE11 (IgM), derived from the same donor. They displayed an identical reaction pattern with 76 Epstein-Barr virus-transformed cell lines. Of these, 29 lines were completely HLA-typed and both antibodies recognized all cells expressing DPwl (six lines), DPw3 (five lines), or DPw5 (three lines). In addition, they bound to one out of four DPw2+ cells and three out of four DPblank+ cells. This specificity correlated strikingly with a characteristic DP beta amino acid sequence (DEAV) at positions 84-87 that had been determined by others. Binding of 125I-labeled TrB50 to lymphoblastoid cells was inhibited by unlabeled IVA-12 (anti-DR + DP monomorphic) and by TrE11. Furthermore, antigens in lysates from TrB50+TrE11+ cells cross-linked TrB50 and TrE11 to the monomorphic anti-DP monoclonal antibody B7/21. Collectively the data provide strong evidence that the epitopes reside on DP molecules. TrE11 can be used to type for this DP beta supertypic specificity by microcytotoxicity using isolated blood B lymphocytes as targets or by a rosette assay directly on whole blood.