Cell-mediated immunity in mice with primary, secondary and latent herpes simplex virus infection.

Cell mediated immunity was studied by a cytopathic effect inhibition assay in mice infected in the ear with herpes simplex virus type 1 (HSV 1). Activity appeared rapidly, reaching a high level 6 days after primary infection. It had fallen 10 days after infection and was undetectable during latency, 3-5 weeks after infection. The activity reappeared even more rapidly and strongly after reinoculation with the virus, but stimuli designed to induce recurrent disease did not induce clinical disease in the animals and no activity was detected in them. The activity, which was specific for HSV, was shown to be mediated by T-lymphocytes.