Characterization of Immune Responses Induced by Combined Clade-A HIV-1 Recombinant Adenovectors in Mice

Background: Numerous evidences indicate that in some HIV-1 positive patients, the humoral and cellular immune responses are induced against HIV-1 proteins and this is inversely related to the progress of infection. Objective: The aim of this study was the evaluation of the Adenovectors containing HIV genes in induction of immune responses in mice. Methods: The HIV-1 genes including gag p24, rev, nef and exon-1 of tat were amplified from HIV-1 RNA (clade-A). The cDNA of each gene was cloned into a transfer vector. The transfer vector was then co-transformed into E. coli strain BJ5183 together with pAdenovector ΔE1/E3. The recombinant adenoviral construct was transfected into QBI-293A cells. Recombinant viruses were purified and titrated on 293 cell plates. Expression of transgenes was evaluated using western blotting. Then 1012 viral particles were injected into 15 groups of 5 mice and all patterns of combination of these 4 HIV-1 genes were evaluated. After 2 weeks, humoral and cellular immune responses were evaluated using ELISA, cell proliferation and ELISpot (IL-2, IL-4 and IFN-γ) assays, consecutively. Results: It was demonstrated that each gene was expressed. The response targets were mostly toward Th1, though several Th2 responses were also observed. Single injection in our study induced a good cellular response but the humoral responses were not as strong as the cellular ones. Conclusion: Considering and comparing all results and evaluating the various possible interactions revealed that simultaneous injection of tat and gag has enhanced the humoral and cellular responses.