Tumor-dependent resistance of rat peritoneal macrophages to herpes simplex virus.

By their position at sites of initial infection and their wide distribution in major organs of the body, macrophages may be decisive in determining the susceptibility or resistance of the host to virus infection. Macrophage restriction of virus replication has been shown to be closely related to virus strains or virus types and to the age of the infected host. We report the effects of the development of a solid tumor in rats on intrinsic in vitro macrophage activity against herpes simplex virus type 1. The results obtained with the infectious center assays and the analysis of single-cycle growth curves of herpes simplex virus type 1 in macrophages obtained from normal and tumor-bearing rats showed a depression of antiviral activity of macrophages from tumor-bearing rats. The possibility of immunomodulation by bacterial adjuvants on tumor-bearing rats and the effects on the antiviral activity of peritoneal macrophages were furthermore demonstrated.