EFFECTS OF INFLUENZA VIRUS-SPECIFIC CYTOTOXIC T-LYMPHOCYTE RESPONSES INDUCED BY A SYNTHETIC NUCLEOPROTEIN PEPTIDE ON THE SURVIVAL OF MICE CHALLENGED WITH A LETHAL DOSE OF VIRUS

Even though virus-induced cytotoxic T lymphocytes (CTLs) recognize ant igens as peptides presented on infected cells, short synthetic peptide s without any modifications are generally considered unsuitable for in ducing antigen-specific CTLs in vivo. Our results demonstrate rapid in duction of influenza virus-specific CTLs in Balb/c mice by an unmodifi ed core protein peptide known to be a dominant H-2(d)-restricted CTL e pitope. Additionally, the immunization procedure we employed in these studies produced significant influenza virus-specific CTLs in lymph no des, spleen and lungs. When challenged with a lethal dose of influenza virus, a statistically significant delay in the day of death was obse rved in peptide-immunized mice. However, viral clearance was only slig htly different from that in control mice. While these results are enco uraging, they suggest a requirement for multiple CTL-inducing peptides , helper T cell-inducing peptides and/or virus-specific IgA responses in order to achieve protection from influenza infection.