FIG 2.

Effect of low-pH pretreatment of HSV-1 on attachment to cells. Extracellular HSV-1 KOS virions were treated with pH 7.4 or 5.0 for 10 min and then neutralized to pH 7.4 for 10 min. Heparin (2 μg/ml) was used as a positive control to inhibit attachment. Treated virions (40 genome copies per cell) were bound to Vero cells for 1 h at 4°C. Cells were washed three times with PBS, and cell-associated virions were quantitated by qPCR. Data are the means from four replicates with standard errors. The P values were determined using Student's t test. Results are representative of three independent experiments.