Replication of ICP0- and ICP4- viruses in cell culture and immunodeficient mice. Vero cells were A. untreated or B. treated with 200 U per ml of IFN-β and were inoculated with 2.5 pfu per cell of wild-type HSV-1 (KOS), an ICP0- virus (0--GFP), or an ICP4- virus (n12). The mean ± sem of the logarithm of viral titers recovered from Vero cells is plotted over time (n = 4 per time point). C. Rag2-/- stat1-/- mice and D. rag2-/- mice were inoculated with 2 × 105 pfu per eye of the ICP0- virus 0--GFP or the ICP4- virus n12 (n = 4 mice per group). The mean ± sem of the logarithm of viral titers recovered from mouse eyes is plotted over time (open black symbols). Dashed lines indicate the lower limit of detection of each plaque assay. The survival of 0--GFP-infected mice and ICP4- virus-infected mice is plotted over time (open red symbols).