In vitro antiviral activity of dermaseptins against herpes simplex virus type 1*

The in vitro antiviral activity of dermaseptins (S1-S5) against herpes simplex virus type 1 (HSV1) was investigated. These peptides were incubated with the virus and its target cells under various conditions, and their effects were examined by the cytopathic effect inhibition assay or by reduction in virus yield in Hep-2 cell cultures as well as by direct immunofluorescence. Dermaseptin S4 displayed the strongest antiviral effect against HSV1, at micromolar doses. Experiments including acyclovir as a reference antiviral agent were performed to investigate the mode of action of this dermaseptin. In contrast to acyclovir, dermaseptin S4 showed its inhibitory effect only when applied to the virus before, or during virus adsorption to the target cells. This suggested that the activity of this dermaseptin was exerted at a very early stage of the viral multiplication cycle, most likely at the virus-cell interface.