Natural killer cellular cytotoxicity against herpes simplex virus-infected cells in Igh-1-disparate mice

Susceptibility to Herpes simplex virus type 1 (HSV-1) stromal keratitis (HSK) in the mouse has previously been linked to the Igh-1 locus. The role of natural killer cells (NK) in resistance to viral infections is controversial. The authors studied the influence of the Igh-1 locus on in vitro murine NK activity against HSV-1 infected cell lines. The HSV-1 infected targets were lysed better than uninfected cells by murine splenic lymphocytes. Strain had no influence on virus-augmented cell lysis. Spleen cells from naive HSK-susceptible CAL-20 (Igh-1d) and BALB/c (Igh-1a) mice lysed YAC-1 targets better than HSK-resistant C.B-17 (Igh-1b) mice. The reverse was seen 24 hours after in vivo infection intraperitoneally with HSV-1. In contrast, CAL-20 splenocytes lysed PU5-1R targets better than BALB/c and C.B-17 splenocytes 24 hours after intraperitoneal (IP) infection. No significant differences were detected in interferon (IFN) levels after IP challenge with HSV-1 among the Igh-1 congenics. The data show that differences in NK activity were determined by both the Igh-1 genotype and the uninfected target cell. Susceptibility to HSK in these Igh-1-disparate congenics thus cannot be explained simply by differences in NK activity against HSV-1-infected targets.