Adult male Syrian hamsters were inoculated subcutaneously with herpes simplex virus type 1 (HSV-1, 10(6) PFU) or ultraviolet-inactivated HSV-1. One week later 12-O-tetradecanoylphorbol 13-acetate (TPA, 2 x 20 nmol weekly) was topically applied to the dorsal skin at the site of virus inoculation for