Pathogenesis of genital herpes simplex virus infection in mice. III. Comparison of the virulence of wild and mutant strains.

This study was undertaken to establish the role of virulence of various herpes simplex virus (HSV) strains in the course of infection when applying the virus to the non-injured mucous membranes of mice. Wild-type HSV-type 1 (HSV-1) strains with marked differences in their neurovirulence following intracerebral inoculation showed minor differences in virulence after vaginal inoculation, but essentially their neurovirulence in cerebral infection corresponded to their virulence on the mucous membranes. In comparison with the wild-types, however, there were pronounced differences among syn- and TK--mutants of HSV-1 and HSV-2 in the degree of virulence at different sites in the course of virus infection. Whereas syn-mutants proved avirulent on the mucous membranes but not in neural tissues, TK--mutants were avirulent both on mucous membranes and in neural tissues. Ts-mutants of HSV-2 were not found to establish themselves when administered to the non-injured mucous membranes, nor did they induce neutralizing antibodies, but a later challenge with the wild-type virus at the same site lead only to an attenuated course of infection.