Effect of imiquimod as an adjuvant for immunotherapy of genital HSV in guinea-pigs.

Imiquimod, an immunomodulator which upregulates cell-mediated immune responses, was evaluated as an adjuvant for immunotherapy of recurrent genital herpes simplex virus (HSV) infection in guinea-pigs. In two experiments at separate research centres, animals were immunized with HSV glycoprotein and either placebo, 1 or 5 days of imiquimod, or complete Freund's adjuvant, 14 and 35 days after genital HSV-2 infection. Recurrent lesion days were then evaluated from days 15-91. In both experiments, immunization with glycoprotein and imiquimod most effectively reduced recurrence compared with unimmunized controls (53-69%, p < 0.001-0.05). A peak reduction of 70-80% was observed following the second immunization. This reduction was greater than that provided by immunization with glycoprotein and complete Freund's adjuvant in these experiments or those previously reported.