Effect of NK cell depletion on innate resistance to HSV-1. BALB/c mice and BALB/c scid mice, inoculated with 2 × 105 pfu/eye HSV-1 strain KOS, received i.p. injections of PBS, control IgG or anti-asialo GM1 (1.2 mg) on days -1, 2, 4, 6, 8 and 10 p.i. A. Viral replication in the eyes of BALB/c mice and scid mice treated with PBS, control IgG or anti-asialo GM1 (mean ± SEM; n = 9; dashed line denotes lower limit of detection). Asterisks denote times at which anti-asialo GM1-treated BALB/c mice shed more virus than PBS-treated BALB/c mice (p < 0.05, ANOVA and Tukey's post hoc t-test). B. Duration of survival of HSV-1 infected BALB/c mice and scid mice treated with PBS, control IgG or anti-asialo GM (n = 9 per group).