Internalization of gB in KgBY889A-infected cells. The same experiment as that described in Fig. 1 was reproduced in 143B cells infected with a virus expressing a mutated YTQV→ATQV gB protein. Subcellular localization of surface-stained gB was analyzed by confocal microscopy as described in the legend for Fig. 1. (A, E, I, M, and Q) Incubation for 0 min at 37°C; (B, F, J, N, and R) 15-min incubation at 37°C; (C, G, K, O, and S) 30-min incubation at 37°C; (D, H, L, P, and T) 60-min incubation at 37°C. Cells were fixed with methanol and then stained with anti-TGN 46 and anti-VP5 antibodies. Panels A to D show phase-contrast images of the different time intervals analyzed. Panels E to H show immunostaining with VP5 (green). Panels I to L show immunostaining with TGN 46 (blue). Panels M to P show immunostaining with anti-gB antibodies (red). (Q to T) Merged images.