An ICP0- virus induces a protective immune response against HSV-1. Strain 129 mice were inoculated with 2 × 105 pfu per eye of the A. ICP0- virus 0--GFP or B. the ICP4- virus n12 (n = 6 mice per group). Rag2-/- mice were inoculated with 2 × 105 pfu per eye of the C. ICP0- virus 0--GFP or D. the ICP4- virus n12 (n = 6 mice per group). The mean ± sem of the logarithm of viral titers recovered from mouse eyes is plotted over time (black symbols). The survival of 0--GFP-infected mice and ICP4- virus-infected mice is plotted over time (red symbols). On day 30 p.i., 0--GFP-infected and ICP4- virus-infected mice were secondarily challenged with 2 × 105 pfu per eye of HSV-1 strain McKrae. Viral titers recovered from the eyes of strain 129 mice or rag2-/- mice after secondary challenge with McKrae is plotted over time (blue symbols). Dashed lines indicate the lower limit of detection of the plaque assay.