In vitro susceptibility of newborn murine retinal cells to herpes simplex virus type 1 infection.

We have investigated the in vitro susceptibility of murine neural retinal cells to infection by herpes simplex virus Type 1 (HSV-1). Retinal cells obtained from newborn C57B1/6 mice were cultured for 6 days and infected with varying doses of HSV-1. Infection was determined by ABC immunoperoxidase staining of fixed cultures for HSV-1 antigens. Retinal neurons, including amacrine cells, were highly susceptible to infection, with 100% of the multipolar neurons expressing viral antigens after 12 hr of infection. Glial cells and retinal pigment epithelial (RPE) cells also were 100% infected within 12-16 hr. Photoreceptor infection was not as fast, but all surviving photoreceptor cells and their precursors became infected by 24-48 hr postinoculation. Since embryonic chick photoreceptors are highly resistant to HSV-1, these results demonstrate that mammalian (murine) photoreceptor cells differ from avian photoreceptor cells in their susceptibility to in vitro HSV-1 infection. In addition, our current results suggest that the in vivo resistance of adult C57B1/6 mice to herpetic retinitis may not reside at the level of the individual retinal cell populations, although apparent differences in susceptibility exist among the various retinal cell subpopulations.