Indirect immunofluorescent assay of the US11 protein in Vero cells infected with HSV-1. (A) HSV-1 infected Vero cells probed with the preimmune serum. (B) Mock infected and (C) HSV-1 infected Vero cells probed with the US11 antiserum. Cells were labeled with FITC-conjugated goat anti-rabbit immunoglobulin G (A-C) and counterstained with Hoechst to visualize the nuclei (D-F). Magnification, 40×.