CHARACTERIZATION OF AN OVERLAPPING CD8(-CELL EPITOPE ON RUBELLA CAPSID PROTEIN() AND CD4(+) T)

A synthetic peptide corresponding to rubella virus capsid protein resi dues 263 to 275 which contains an epitope recognized by a cloned CD4() cytotoxic T-lymphocyte (CTL) line was used to induce CD8(+) T-cell l ines specific to this peptide. A peptide-specific CD8(+) CTL clone was derived and characterized. This peptide-specific CD8(+) CTL clone exh ibited cytotoxicity against target cells infected by a vaccinia recomb inant virus expressing rubella virus capsid protein, but not by target cells infected by vaccinia recombinant virus expressing rubella virus E1 or E2 envelope proteins. Analysis of HLA class I restriction of th e CD8(+) CTL clone revealed that A11 and A3 were restrictive elements, Fine mapping with truncated and overlapping peptide analogs revealed a nonamer sequence, C(264-272), as the T-cell epitope eliciting strong er cytotoxicity. Two anchor residues for binding to HLA A11 and A3 wer e identified at position 2 (isoleucine) and at position 9 (histidine) or at position 8 (arginine) of the epitope sequence. The identificatio n of overlapping CD4(+) and CD8(+) T-cell epitopes within the capsid p rotein sequence C(263-275) implicates a strategy for using such epitop es in a candidate peptide-based rubella vaccine. (C) 1997 Academic Pre ss.