Comparison of effects of the D286R and null mutation in UL31 on viral growth in Vero and HeLa cells. (A and B) Vero cells were infected with wild-type HSV-1(F), YK726 (UL31-D286R), YK727 (UL31-D286R-repair), or YK720 (ΔUL31) at an MOI of 3 (A) or 0.01 (B) and harvested at 24 h (A) or 48 h (B) after infection. (C and D) HeLa cells were infected with wild-type HSV-1(F), YK726 (UL31-D286R), YK727 (UL31-D286R-repair), or YK720 (ΔUL31) at an MOI of 10 (C) or 0.05 (D) and harvested at 36 h (C) or 72 h (D) after infection. Cells and supernatants were titrated in UL31-CV-1 cells. Each data point is the mean ± standard error from 3 (A and B) or 4 (C and D) independent experiments. *, P < 0.05 (the unpaired Student's t test).