FIG. 1.

Direct inactivation of virus by NP-1. Laboratory and clinical isolates of HSV (at a concentration of ∼10⁸ PFU/ml) were mixed with increasing concentrations of NP-1 (or 0.1% acetic acid diluted in PBS for control) and incubated at 37°C for 1 h. The virus-drug mixture was then diluted to yield 100 to 500 PFU/ml and noninhibitory concentrations of drug prior to infecting cells. Plaques were quantified 48 h postinfection. Results are presented as PFU formed in the presence of NP-1 as a percentage of PFU formed in the presence of control buffer. Each point is the mean of two independent experiments performed in duplicate; error bars indicate standard deviations. Isolates include the laboratory strains HSV-1(17) and HSV-2(333) and the clinical isolates WTW1A, MMA, DT-1 (acyclovir susceptible), and DT-2 (acyclovir resistant).