The inhibitory effect of PEgylated rIPs on herpes simplex virus-1 VERO cells were cultured to logarithmic growth phase in 10 mL DMEM containing 10% (v/v) fetal bovine serum, 100 µg/mL penicillin, and 100 U/mL streptomycin. After removing medium, cells were substituted to 5 mL of the above medium and infected with 100 µL of herpes simplex virus-1 (HSV-1) for 1.5 hours. Then, 5 mL maintenance medium containing 2% (v/v) fetal bovine serum, 100 µg/mL penicillin, and 100 U/mL streptomycin was added and cells were continually cultured for about 1-2 days when over 80% cells appeared with cytopathic effect (CPE). The infected supernatant was collected for testing of virus titers.