Effects on herpes simplex virus type 1 of combined use of interferon-beta and anti-herpetic agents in vitro.

It has been shown that the use of interferon (IFN) alone has little or no therapeutic effect in the treatment of herpetic keratitis. However, IFN used in combination with anti-herpetic agents has high therapeutic efficacy. This interaction between IFN and anti-herpetic agents has not been elucidated clearly. In this study, the interaction between human fibroblast interferon (HuIFN-beta) and anti-herpetic agents, 5-iodo-2'-deoxyuridine (IDU), aciclovir (ACV) and 9-(1,3-dihydroxy-2-propoxymethyl)guanine (DHPG), was studied in vitro using VERO cells. After the formation of a monolayer of VERO cells, HuIFN-beta of various concentrations was added to the maintenance medium. After 24 hours incubation, the medium was removed and herpes simplex virus (HSV) type 1 was inoculated on the VERO cells. Then, anti-herpetic agents were added to the medium in various concentrations. After 48 hours incubation, plaques were counted and the reduction rate in numbers of plaque was calculated. It was found that the combination of HuIFN-beta with IDU, ACV or DHPG worked synergistically in the inhibition of HSV replication.