Antiviral Effect of TNF-α and IFN-γ Secreted from a CD8 + Influenza Virus-Specific CTL Clone

We observed that an influenza-specific cytotoxic T lymphocyte (CTL) clone (B7B7) stimulated with peptide-antigen could produce TNF-alpha and IFN-gamma simultaneously. The culture supernatant containing both TNF-alpha and IFN-gamma of antigen-stimulated CTL clone B7B7 significantly enhanced the lysis of influenza A/PR/8 virus-infected L-M2d6 cells or Meth A cells. Enhanced lysis of influenza virus-infected cells by the supernatants was inhibited by pretreatment of the supernatant with antimurine TNF-alpha antibody and antimurine IFN-gamma antibody. In addition to a single CTL clone, we observed that bulk-cultured CTLs were able to produce TNF and IFN when incubated with target cells. These results suggest that the protective mechanism mediated by TNF-alpha and IFN-gamma secreted from CTL may be possible in the course of an influenza infection.