FIG. 8.

Effect of a Gly at position 310 of the S protein on receptor-independent spread. 17Cl-1 cells (JHM permissive) infected with rJHM.IA (A, D, and G), rJHM.SD (B, E, and H), or rJIA.S.S310G (C, F, and I) were overlaid onto CFSE-labeled uninfected 17Cl-1 cells (A through C) or BHK cells (non-JHM permissive) (D through I) at a 1:50 ratio as described in Materials and Methods. At 20 h p.i., cells were fixed, and viral antigen was detected by sequential treatments with an anti-N antibody and a Texas red-conjugated goat anti-mouse antibody. Cells were visualized by fluorescent microscopy. Green fluorescence, CFSE labeling; red fluorescence, Texas red labeling. Only CSFE-labeled cells are shown in panels A through C.