Structure-Based Mutations in the Herpes Simplex Virus 1 Glycoprotein B Ectodomain Arm Impart a Slow-Entry Phenotype

Fan, Qing; Kopp, Sarah J.; Connolly, Sarah A.; Longnecker, Richard

gB 3A viruses exhibit a growth delay. GS3217 (WT), gB 3A-1, and gB 3A-2 viruses encode tdTomato, allowing infection to be monitored by fluorescence microscopy. Vero cells were infected with viruses at 0.01 PFU/cell and incubated for 24 to 144 h before imaging. By microscopic examination at 24 h postinfection (hpi), 30 to 50% of the cells infected with GS3217 (WT) virus were red, whereas very few red cells were observed with both the gB 3A-1 and gB 3A-2 viruses (Fig. 2) . At 48 hpi, all of the cells infected with GS3217 (WT) virus were red and the cytopathic effect (CPE) of infection was widespread. The cells infected with the gB 3A viruses did not achieve this level of infection and CPE until 4 to 6 days postinfection (Fig. 2) .