FIG. 5.

Effect of NP-1 on cell-to-cell spread. Vero cells were infected with HSV-2(333) at 37°C to allow viral entry and treated with citrate buffer 2 h after infection to inactivate residual extracellular virus. Five hours after infection, cells were trypsinized, counted, and plated onto monolayers of uninfected cells in the presence of pooled human immunoglobulin to neutralize released virus and 0.1% acetic acid (left) or 25 μg of NP-1/ml (right). After 48 h plaques were visualized by immunostaining.