Reversibility of pH-induced conformational changes in ANG path gB. (A) HSV-1 ANG path or KOS virions were treated with medium buffered to pH 7.4 or 5.3. For the indicated samples, pH was neutralized back to 7.4 for 5 min at 37°C. Virions were blotted immediately to nitrocellulose. Membranes were probed at neutral pH with antibodies H126, SS106 or H1817 followed by horseradish peroxidase conjugated secondary antibody. The exposures shown document the reversibility of reactivity. (B) ANG path or KOS virions were treated with pH 7.4 or 5.2. Where indicated virions were neutralized back to pH 7.4. Samples were treated with 1% SDS, and then analyzed by "native" PAGE. Immunoblots were probed for detection of gB.