FIG. 10.

Virucidal assay. (A) hrR3 virus (1.2 × 10⁶ PFU/ml) was treated with EB (●) or EBX (○) at the indicated concentrations for 1 h at 37°C in serum-free DMEM, diluted 200-fold with serum-supplemented DMEM, and assayed for remaining infectious virus. (B) hrR3 virus was again treated with EB and assayed exactly as in panel A. In addition, aliquots of diluted virus were dialyzed overnight at 4°C against serum-supplemented DMEM (Δ) or filtered through 0.22-μm-pore-size membranes (▴) before they were assayed for remaining infectious virus. Virions recovered after dialysis (31 ± 1.8% [n = 8]), irrespective of the EB concentration, remained inactivated exactly as in nondialyzed controls (Δ, normalized to untreated control [left scale]). Retention of virions on membranes depended on EB concentrations (▴, percentage of controls [right scale]). Triplicate counts of lacZ⁺ cells were performed 8 h after infection. All points are means with standard errors of the means. Scores of untreated controls were 1,245 ±11 (n = 3) (A) and 1,876 ±67 (n = 3) (B).