Immunogenicity of DNA vaccines encoding structural proteins and regulatory/accessory proteins derived from an HIV-1 CRF01_AE isolate circulating in China
Objective To construct two DNA vaccines encoding Gag-Env fusion protein and Tat-Rev-Integrase(C-half)-Vif-Nef fusion protein derived from the first HIV-1 CRF01_AE isolate(AE2f) in Chi-na and to evaluate the immunogenicity in mice. Methods Two DNA vaccines were constructed by inserting the codon optimized and synthesized gag-env fusion gene and tat-rev-integrase(c-half)-vif-nef fusion gene de-rived from AE2f into mammalian expression vector pDRVISV1. 0, the generated DNA vaccines were desig-nated as pSVAE/GE and pSVAE/TRIVN, respectively, and their in vitro expression were determined by Western blot with transfected 293T cells. Mice were i. m. immunized with either pDRVI1.0 as mock control, pSVAE/GE or pSYAE/TRIVN for 4 times at two-week interval. Two weeks following the final im-munization, cellular responses to pool of HIV-1 Env, Gag, Tat, Rev, Intergrase, Vif and Nef peptides were evaluated by ELISPOT assay. Results The construction of DNA vaccine pSVAE/GE and pSVAE/TRIVN was validated by restriction enzyme digestion and bidirectional sequencing. Western blot showed a specific band at molecular mass 220×10~3 in lane of pSVAE/GE transfeeted 293T cell and a specific band at 95×10~3 in the lane of pSVAE/TRIVN. Both DNA vaccines mounted significant specific T cell responses with (3010 ± 566) SFC/10~6 splenocytes for DNA vaccine pSV AE/GE and (948 ± 737) SFC/10~6 spleno-cytes for DNA vaccine pSVAE/TRIVN, whereas the mock control of pDRVISV1.0 only raised marginal T cell responses. Conclusion Both pSVAE/GE and pSVAE/TRIVN were capable of expressing the inserted fusion immunogen genes and able to elicit vigorous cellular immune responses, therefore, these DNA vac-cines are highly immunogenic. 
 
Key words: 
HIV-1;  AIDS vaccine;  Structural gene;  Regulatory gene