Figure 1. Immunocytofluorescence analysis of the efficacy of TONS 504–PACT against HSV-1 and ACV-resistant HSV-1. Uninfected FL cells (A) as well as FL cells infected with herpes simplex virus type 1 (HSV-1) and either left untreated (B) or subjected to TONS 504–photodynamic antimicrobial chemotherapy (PACT) at a light-emitting diode (LED) energy of 20 J/cm² and TONS 504 concentrations of 0.1 mg/l (C), 0.5 mg/l (D), 1 mg/l (E), or 10 mg/l (F) were subjected to immunocytofluorescence staining with antibodies to HSV-1 (green fluorescence). Cell nuclei were also stained with 4′,6-diamidino-2-phenylindolse (DAPI; blue fluorescence). Similar results were obtained for cells infected with two strains of acyclovir (ACV)-resistant HSV-1. Scale bars, 100 μm.