PROMISCUOUS T-CELL RECOGNITION OF A RUBELLA CAPSID PROTEIN EPITOPE RESTRICTED BY DRB1-ASTERISK-0403 AND DRB1-ASTERISK-0901 MOLECULES SHARING AN HLA DR SUPERTYPE

Two T cell clones derived from different donors with HLA-DRB10403 or DRB10901 phenotype recognize a rubella capsid peptide, C(265-273) in the context of several different HLA-DR molecules in addition to DRB 0403 and DRB10901. All DR molecules restricting the T-cell clones hav e in common residues, R or Q at position beta 70, R at position beta 7 1, and E at position beta 74 in pocket '4' of the DR peptide binding g roove, suggesting that a DR subregion structure or supertype, ''Q/RRE' ' underlies the promiscuous T-cell recognition of this peptide. Single amino acid substituted analogs of peptide C(263-275) at anchor positi on 4 for natural residue R were tested for their ability to induce clo nal T-cell cytotoxic responses. The results indicated that a positivel y charged residue, R or K, was required for T-cell recognition, sugges ting a possible mechanism of electrostatic interactions between the ne gatively charged residue E at position beta 74 of these DR molecules a nd the positively charged residue at anchor position 4 of the peptide in T-cell recognition. (C) American Society for Histocompatibility and Immunogenetics, 1998. Published by Elsevier Science Inc.