CLONED PRIMED LYMPHOCYTE TEST CELLS RECOGNIZE THE 4TH, 5TH, AND 6TH HYPERVARIABLE REGIONS AT AMINO-ACID POSITIONS-65-87 OF THE DPB1 MOLECULE

Genetic polymorphisms of the HLA-DPB1 gene in Japanese and Caucasian p anel cells defined by PLT were analyzed by the PCR-based genotyping te chnique PCR-RFLP, and suballeles of DPw3 (DPB103) and DP''Cp63'' (DPB 109) could be detected. PLT-defined DPw3 cells were typed by PCR-RFLP as either DPB10301 or DPB1*1401. On the other hand, PLT-defined DPCp 63-typed cells were typed as DPB10901 or DPB1*1001. These results ind icate that both DPw3 and DPCp63 are split into two subantigens. DPw2 a nd DPw4 are DPB10201 and 0202 and DPB1*0401 and 0402, respectively. C omparative analysis of the amino acid sequences of the DPw2-, DPw4-, D Pw3-, and DPCp63-associated alleles revealed that the fourth (C), fift h (D), and sixth (E) hypervariable regions at amino acid positions 65- 87 were shared within the same PLT-defined DP antigen groups, suggesti ng that these three hypervariable regions are recognized by cloned T c ells in PLT, thus determining DP antigen specificity. On the basis of this model, 44 DPB1 alleles can be classified into 18 antigen groups, each of which may possibly represent a PLT-defined single DP specifici ty.