[Study on vector-specific and foreign gene-specific immune responses induced by rAd5 and rAAV2/1 vaccines].

OBJECTIVE: To compare the foreign gene-specific and vector-specific immune responses in BALB/c mice immunized with rAd5 or rAAV2/1 expressing the same gene. METHODS: BALB/c mice were immunized with rAd5-gag or rAAV2/1-gag once, HIV-1 Gag-specific and vector-specific cellular immune responses were analyzed by Elispot assay, HIV-1 P24-specific IgG and vector-specific IgG were tested by ELISA assay. RESULTS: Mice immunized with rAd5-gag induced potent Gag-specific cellular immune responses and that were significantly higher than Ad5-specfic cellular responses, while rAAV2/1-gag elicited weak Gag-specific and AAV2/1-specific cellular responses. Both P24-specific and Ad5-specific IgG titers induced by rAd5-gag were high and in similar level. Higher level of P24-specific IgG was found in mice inoculated with rAAV2/1-gag than rAd5-gag. And the P24-specific IgG titers were higher than the vector-specific IgG titers in mice immunized with rAAV2/1. CONCLUSION: rAd5 could elicit strong foreign gene-specific cellular and humoral immune responses, weak vector-specific cellular responses and strong vector-specific antibodies, rAAV2/1 could induce potent foreign gene-specific antibodies that were much higher than vector-specific IgG, while both foreign gene-specific and vector-specific cellular responses were very low.