In vitro VZV neutralization. Purified VZV-specific monoclonal antibodies were tested for in vitro neutralization as described in Materials and Methods. Using an Acumen Cellista, the total number of cells expressing GFP per well was quantified. (A) Cumulative results with and without complement. (B) Cumulative IC50 results (in μg/ml) for all antibodies that showed neutralization with or without the addition of guinea pig complement. (C) Representative neutralization plots with gH-, gE-, and gI-specific monoclonal antibodies added. Red, guinea pig complement added; blue, without guinea pig complement.