FIG. 4.
Effect of low-pH treatment on the conformation of purified gB. (A) HSV-1 KOS virions (105 PFU) or s-gB (150 ng) in serum-free medium with 0.2% BSA was kept at pH 7.2 or adjusted to pH 5.5 for 10 min at 37°C with 0.05 N HCl. The pH of acidified samples was reneutralized to 7.2 with 0.05 N NaOH for 10 min at 37°C. Samples were analyzed by native PAGE and immunoblotting with gB-specific PAb R69 or MAb DL16. (B) Soluble gB derived from HSV-2 strain 333 (s-gB) was treated with pH 7.4 or 5.1 and then solubilized with 1% SDS either before or after neutralization of pH (as described in the legend to Fig. 2C). HSV-2 strain 333 virions were also treated at pH 7.4 or 5.1 and solubilized with 1% SDS. (C) s-gB was treated with a range of pH, as indicated, and then solubilized with 1% SDS. Samples were analyzed by PAGE and immunoblotting, with R69 for detection of gB.