SUMMARY

The peritoneal exudate cells (PEC) represent the first line of defence against the virus in the mouse model of intraperitoneal (i.p.) infection with herpes simplex virus (HSV). We have therefore studied interferon production and activation of natural killer (NK) cells in vitro in PEC of HSV-injected mice. Injection of HSV caused a marked increase in NK cell activity, as reported by others. PEC from HSV-injected mice also produced high titres of interferon. This observation may be important since induction of interferon appears to be the primary event whereas ctivation of NK cells- as generally accepted- represents a secondary effect of the interferon produced. The HSV-induced NK cells shared the properties of NK cells in that they were sensitive to a monoclonal nti-theta ntibody and to a monoclonal nti-Qa 5 antibody. In contrast, the cells producing interferon were not sensitive to either antibody. Irradiation (200 R) of the mice 24 h before injection f the virus decreased interferon production by more than 90%. The identity of the interferon-producing ceils is unknown, but they may represent B cells