Induction of genital immunity by DNA priming and intranasal booster immunization with a replication-defective adenoviral recombinant

Mice immunized through different routes such as i.m., intradermally, or int ratracheally with a DNA vaccine to rabies virus developed high titers of se rum Ab but only borderline levels of mucosal Abs determined from vaginal se cretions. DNA vaccines given by either route enhanced vaginal IgA and IgG2a secretion upon a subsequent intranasal booster immunization with an El-del eted adenoviral recombinant expressing the same Ag of rabies virus. DNA vac cine priming reduced the Ab response to the adenoviral Ags and counterbalan ced the impaired B cell response to the rabies virus Ag expressed by the ad enoviral recombinant in mice preimmune to adenovirus. The vaginal B cell re sponse could further be enhanced by using the Th2-type cytokines IL-4 or IL -5 as;genetic adjuvants concomitantly with the DNA vaccine before intranasa l booster immunization with the recombinant vaccine.