Modulation by cyclosporin A of murine natural resistance against herpes simplex virus infection. I. Interference with the susceptibility to herpes simplex virus infection.

Adult BALB/c mice which are medium-high resistant against intraperitoneal (i.p.) infection with herpes simplex virus type 2 (HSV-2) manifested a drastic increase in susceptibility to the virus when treated locally with cyclosporin A (CyA) during infection. Oral application of the drug had no effect on the natural resistance status. Mice appeared normal 2 weeks after CyA treatment with regard to their ability to resist i.p. infections. CyA did not interfere with established specific immune protection nor with the induction in immune responses to HSV-2.