Figure 6.

Deletion or I6E mutation of N1 enhances CD8⁺ T-cell cytotoxicity. (a) Mice were infected intradermally with the indicated viruses and splenic lymphocytes were harvested at 28 days post-infection and tested for their ability to lyse vaccinia virus (VACV) -infected EL4 cells by chromium release assay. Data are presented as percentage cell lysis at various effector to target (E : T) cell ratios. *P < 0·05, **P < 0·01, n = 5. (b) Lymphocytes were prepared as in (a) and pre-incubated with a CD8 blocking monoclonal antibody before cytotoxic activity was assayed as in (a). (c) Lymphocytes were prepared as in (a). Histograms showing the absolute number of CD8⁺ cells expressing CD107a following stimulation with VACV B8 peptide. (d) Cytotoxicity assay as in (a) but with purified splenic natural killer cells and using VACV-infected P815 cells as targets. Results are expressed as mean ± SEM.