[Immunogenicity of a chimeric adenovirus type 5 vector with type 35 fiber containing HIV-1 gag in mice].

OBJECTIVE: To study the immune effect of a chimeric adenovirus type 5 vector with type 35 fiber (rAd5/F35) vaccine in BALB/c mice. METHODS: The expression of HIV Gag protein was determined using indirect immunofluorescent staining. The rAd5/F35-mod.gag vector was injected intramuscularly to mice. The IgG antibody was detected by ELISA and CTL response was detected by intracellular cytokine stain assay. RESULTS: The rAd5/F35-mod.gag vector could express HIV Gag protein in vitro and generate strong HIV-specific immune responses in vivo. But anti-Ad5 immunity could limit its immunogenicity in vivo. CONCLUSION: The rAd5/F35-mod.gag vector can elicit specific CTL response and IgG antibody in animal model. In mice with high Ad5 vector-specific immunity, Ad5/F35-mod.gag showed lower level of Gag specific CTL and antibody response than in mice without pre-existing adenovirus type 5 immunity. The results indicated that fiber exchange alone does not evade pre-existing Ad5 immunity.