VSV-gp160G remains potently oncolytic and is dependent upon CD4 and gp120 interaction. (A and B) HeLa and HeLa CD4+ cells were infected with either VSV-XN2 or VSV-gp160G at an MOI of 0.1. Cells and supernatants were collected at 6, 12, 24, and 48 hpi. Cell death at each time point was determined using annexin V-propidium iodide (PI) staining. Representative gating results are shown. (C) Bright-field microscopy of infected HeLa CD4+ cells pretreated with neutralizing antibody against CD4 (1 μg/well, HeLa CD4+) or gp120 (2 μg/well, VSV inoculum) 1 h prior to infection at 24 hpi. (D) Cell death of VSV-infected HeLa CD4+ cells pretreated with neutralizing antibody was determined using annexin V-PI staining at an MOI of 0.01 at 24 hpi (Student t test, two tailed, equal variance; **, P < 0.001 [panel D, untreated control versus antibody treated]).