FIG. 3.

In vitro inactivation of ALV-A infection by sTva and bTva is dependent upon exposure to acid pH. RCASBP(A)-EGFP virus was exposed to bTva (A) or sTva (B) at the indicated concentrations. After a 20-min incubation on ice, the pH was adjusted to 5.0 (⋄), 5.2 (□), 5.5 (▵), 6.0 (×), 6.8 (*), or 7.5 (○), and samples were incubated for an additional 30 min at 37°C. After neutralization, virus-receptor complexes were spinoculated onto 293-Tva cells, and these cells were analyzed for acquired EGFP expression 48 h later. Viral titers (infectious units per milliliter) were determined by end point dilution. Error bars represent the standard deviation of three measurements.