Abstract
Mice infected with herpes simplex virus either orally or i.p. had a markedly age-related mortality. All animals under 3 wk of age died, whereas all those over 3 wk of age survived. The ability of murine peritoneal cells to kill herpes simplex virus-infected target cells in the absence (natural killer cytotoxicity) or presence (antibody-dependent cellular cytotoxicity) of antiviral antibody was similarly correlated with age and survival. This correlation is further support for the relevance of these antiviral defense mechanisms, and it may help explain the profound susceptibility of neonatal mice to herpes simplex virus infection.