Pathogenesis of genital herpes simplex virus infection in mice. IV. Quantitative aspects of viral latency.

Experiments in the mouse model of herpes simplex virus (HSV) infection involving the intact genital mucous membranes as inoculation site yielded the following results. In untreated mice the extent of latency was correlated with the degree of peripheral virus replication. This correlation could not be observed when the course of infection was interrupted by chemotherapy, interferon, or passive immunization. Acyclovir had little effect on peripheral virus multiplication, but markedly reduced latent ganglionic infection. As acute ganglionic infection and virus concentration in the spinal nerves were already reduced, acyclovir is assumed to inhibit either virus penetration into the nerve endings or virus replication in the ganglia. Interferon apparently has an active role in the elimination of virus infected cells from the ganglia, as its effect was restricted to a reduced rate of latency and of lethality. Passive immunization with antiserum led to similar results as ACV-treatment. While lacking a pronounced effect on virus replication in the mucous membranes, specific antibody was found to influence both virus elimination from the ganglia, and conversion from productive to latent ganglionic infection. Immune lymphocytes proved to be the only agent capable of suppressing peripheral infection, thereby inhibiting the neural spread of the virus. These results suggest that the decrease in latency may result from modulations occurring at different stages in the course of infection.