FIG. 2.

Effect of gDt on HSV-1 entry into Vero cells. Confluent cells on 96-well plates were incubated with various concentrations of purified gDt at 4°C for 90 min. HSV-1(hrR3) was added at an multiplicity of infection of 0.5 PFU/cell, and the plate was incubated for another 90 min at 4°C. Plates were then shifted to 37°C for 5 h. Cells were lysed, and β-galactosidase activity was measured on aliquots of the cytoplasmic extract, using the substrate chlorophenol red-β-d-galactopyranoside and measuring the increase in absorbance over 50 min at 570 nm; 100% entry corresponds to no added inhibitor. (A) Blocking of entry with gD1(306t) compared to that of the region IV mutants; (B) blocking of entry with gD1(306t) (same curve as in panel A) compared to that of the other truncation mutants.