Role of T-lymphocytes in the pathogenesis of herpetic stromal keratitis

Our study was designed to investigate the mechanism of the stromal reaction in experimental ocular infection of murine eyes with herpes simplex virus (HSV). Severe stromal keratitis with scarring occurred in BALB/c mice after infection of the scarified cornea but similar reactions did not occur in athymic mice. However, if athymic mice were given adoptive transfers of lymphoid cells, a severe necrotizing and ulcerative keratitis accompanied by scarring resulted. The lesion progressed more quickly in recipients of lymphoid cells specifically immune to HSV and containing cytotoxic T-lymphocyte activity. In such mice, necrosis and ulceration were marked on the sixth day after transfer compared with 9-12 days for those given nonimmune cells. Removal of T-lymphocytes from the immune lymphoid population by treatment with specific antiserum and complement abrogated the adoptive transfer of the stromal reaction. Our results further demonstrate that stromal keratitis represents a host immunopathologic response to HSV infection in which T-lymphocytes are essential participants. Multiple mechanisms of T-cell immunopathology appear to be operating, including a reaction mediated by cytotoxic T-lymphocytes.