DEMONSTRATION OF VIRUS-SPECIFIC CD8(-CELLS IN MEASLES-SEROPOSITIVE INDIVIDUALS BY IN-VITRO PEPTIDE STIMULATION() MEMORY T)

CD8(+) cytotoxic T lymphocytes (CTL) in measles virus infection have b een difficult to investigate due to the strong immunosuppressive effec ts exhibited by infectious measles virus in vitro. In order to circumv ent immunosuppression we used predicted peptide epitopes to induce mea sles virus-specific CTL. This was done by screening the structural pro teins of measles virus for HLA-A2.1 peptide-binding motifs with valine in position 2 and leucine in position 9. Synthetic peptides np210-218 , np226-234, and np340-348 from the nucleoprotein, peptide hp29-37 fro m the haemagglutinin protein, and peptide pp 519-527 from the polymera se protein were synthesized and used to expand measles virus-specific CD8(+) CTL in vitro. Induction of CTL with synthetic peptides was rest ricted to HLA-A2-positive peripheral blood mononuclear cells (PBMC) fr om measles-seropositive individuals. We conclude that this method is a useful tool to demonstrate memory CD8(+) CTL in measles-seropositive adults and to evaluate the role of structural proteins in CTL response s against measles.