FIG 4.

ACV and compound 118 synergistically inhibit HSV-2 replication and DNA accumulation. ACV and compound 118 were diluted in 3-fold steps and added alone or together in constant ratios to Vero cell monolayers infected with HSV-2 at an MOI of 0.1. After 24 h, the cultures were collected and divided into two aliquots. Shown are a representative volume plot of viral titers for combinations of ACV and/or compound 118 against HSV-2, as determined by a plaque assay (A), and isobolograms for qPCR for HSV-2 genomic DNA (B) and viral titer (C) data, as analyzed by the Chou-Talalay method. In panels B and C, the x axis indicates the effective concentration in this experiment for compound 118 alone, and the y axis indicates the effective concentration for ACV alone. The colored lines represent efficacy expected from mixing compound 118 and ACV at various proportions if the effects of the compounds are additive. The area below the lines indicates synergism, and the area above indicates antagonism. EC₉₀, EC₇₅, and EC₅₀ values were calculated in this experiment from the combinations of compound 118 and ACV.