The role of natural killer cells in murine cytomegalovirus eye infection.

PURPOSE To study the role of natural killer cells in the dissemination of virus to the eye and virus growth as well as the production of lesions in the eye during primary infection of murine cytomegalovirus. METHODS Virus activity and lesion production by murine cytomegalovirus in various organs of natural killer cell-depleted BALB/c strain of inbred mice were compared with those of immunocompetent normal BALB/c mice. RESULTS In mice injected intraperitoneally with murine cytomegalovirus, virus could be isolated from 50% of eyes in the natural killer cell-depleted group whereas no virus was detected from any eye in the control group. In natural killer cell-depleted mice with positive virus isolation from eyes, no murine cytomegalovirus was isolated from either optic nerves or trigeminal ganglia whereas virus was detected from blood lymphocytes, macrophages, granulocytes, and plasma. After intravitreal injection of murine cytomegalovirus, virus titers in eyes of natural killer cell-depleted mice were significantly higher than those in the control group. Derangement of retinal cell layer and inflammatory cells as well as cytomegalic cells in iris and ciliary body were noted in natural killer cell-depleted group, whereas no such changes were observed in the eyes of the control mice. CONCLUSION Natural killer cell depletion enhances the dissemination of murine cytomegalovirus to the eye through the hematogenous route, and increases virus multiplication as well as lesion production in the eye.