Fig. 6.

NK cell cytotoxicity and the effects of NK cell depletion during influenza virus infection. C57BL/6 mice were sensitized and challenged with OVA or PBS. The cells in the spleen were considered to be effector cells and were prepared from asthmatic mice or control mice on day 0 before the infection. The titrated effector cells and 1 × 10⁵ cells ml⁻¹ of YAC-1 cells were co-cultured at various effector/target ratios, as indicated in the figure. The cytotoxicity percentages were calculated as described in the “Materials and Methods” (a). Asthmatic mice were injected i.v. with normal rabbit serum or anti-asialoGM1 serum on days −4 and 0 before the infection. The survival rate (b) and body weight (c) were monitored daily until day 20. The body weight data of the mice that died were excluded from the day of death onwards. Twelve mice were used in each group. Similar results were observed from two independent experiments. *p < 0.05 compared to the body weight of control mice on the same day. These results are representative of two or three independent experiments