Immunological studies of herpetic keratitis: induction of cytotoxic T lymphocytes in mouse splenocytes.

C3H/He and BALB/c mice were inoculated with herpes simplex virus (HSV) by corneal or intraperitoneal route. The mouse splenocytes were analyzed to determine the level and mode of cytotoxic T lymphocyte (CTL) induction by a cytotoxicity test, using HSV-infected L929 cells and 3T3 cells as the target cells. To enhance the activities of CTL, mouse splenocytes were restimulated by lipopolysaccharide-induced lymphoblasts (LPS-blasts) infected with HSV before assay. HSV infection by both corneal and intraperitoneal routes induced H-2 restricted T lymphocyte responses specific for HSV. This CTL response became detectable on day 6 in mice with herpetic keratitis and on day 4 with intraperitoneal infection, but 10 days after infection the CTL activities of both groups reached the same level. A high response level persisted as long as 28 days. These results suggest that the protective mechanism in herpetic keratitis is similar to the mechanism in intraperitoneal infection.