Effect of Fas and Fas ligand deficiency in resistance of C57BL/6 mice to HSV-1 keratitis and chorioretinitis

PURPOSE. To investigate the effect of Fas and Fas ligand (FasL) deficiency on the development of herpes stromal keratitis and on the von Szily model o f herpes retinitis in C57BL/6 mice, which are ordinarily resistant to devel opment of both of these herpetic diseases. METHODS. Anterior chamber inoculation of the right eye of each mouse with v arious titers of HSV-1 (KOS strain) was performed. Both eyes of each mouse were enucleated on postinoculation day 15 and processed for histopathologic examination. HSV-1 was inoculated into one cornea of other mice, and the s everity of stromal keratitis was scored. RESULTS. Contralateral destructive chorioretinitis developed in susceptible Balb/cByj mice (19/23); ipsilateral chorioretinitis did not occur (0/23). Stromal keratitis developed in susceptible C.AL-20 mice (15/16). None of th e C57BL/6 (0/10 for keratitis or 0/20 for retinitis) developed inflammation . Neither did B6.SMN.C3H.gld (FasL deficient; 0/12 or 0/28) or B6.MRL.1pr ( Fas deficient; 0/11 or 0/34) mice (keratitis or contralateral chorioretinit is). Minimal scattering of inflammatory cells in the contralateral retina b ut not destructive chorioretinitis was observed in two C57BL/6, three B6.SM N.C3H.gld, and five B6.MRI.1pr mice, Few inflammatory cells were also found in the ipsilateral vitreous and vitreoretinal interface (but not destructi ve chorioretinitis) of all C57BL/6, two gld, and three lpr mice. CONCLUSIONS Immune dysregulation secondary to deficiency in Fas or FasL sys tem does not influence the resistance of the C57BL/6 mice to develop herpes simplex keratitis or destructive herpes simplex chorioretinitis.