Adjuvant effects of imiquimod on a herpes simplex virus type 2 glycoprotein vaccine in guinea pigs.

The adjuvant effects of imiquimod for a herpes simplex virus (HSV) vaccine were evaluated. Guinea pigs were immunized with 35 micrograms of lectin-purified HSV-2 glycoproteins 14 and 35 days before intravaginal HSV-2 inoculation. Immunizations were given either alone, with complete Freund's adjuvant, or with three different 5-day regimens of imiquimod. Although immunization alone decreased the severity of the acute disease and viral replication, in two separate experiments, the addition of imiquimod produced further decreases. The addition of subcutaneous imiquimod further decreased viral shedding by > 3 logs on day 1 after virus inoculation (P < .001). All groups that received immunization and imiquimod also developed significantly fewer HSV recurrent lesion days (P < .05-.001) compared to immunization alone. No recurrent lesions were detected in the group that received immunization and subcutaneous imiquimod. Imiquimod enhanced the effectiveness of HSV-2 immunization, especially in reducing recurrent HSV disease, and should be evaluated further as an adjuvant.