Improvement in efficacy of DNA vaccine encoding HIV-1 vif by LIGHT gene adjuvant

DNA vaccine can induce the prolonged immune responses against the encoded antigen with the appropriate adjuvant. To study the immunogenicity of the HIV-1 vif DNA vaccine in inducing the humoral and cellular immune responses and the immunoadjuvant effect of LIGHT, which is a member of TNF superfamily and can stimulate the proliferation of naïve T cells as a co-stimulatory molecule, DNA vaccine plasmid pcDNA-Vif was constructed by inserting HIV-1 vif gene into the downstream of CMV promoter in eukaryotic expression vector pcDNA3.1(+). In vitro expression of HIV-1 Vif in pcDNA-Vif-transfected HeLa cells was confirmed in transcriptional and protein level by RT-PCR and Western blot, respectively. After BALB/c mice were injected muscularly with DNA vaccines for three times, the specific immune responses were analyzed. The data showed that anti-Vif antibody response, Vif-specific T cell proliferation, and CTL activities were induced in the mice that were inoculated with HIV-1 vif DNA vaccine plasmid. Interestingly, stronger humoral and cellular immune responses were detected in mice that were immunized with plasmid pcDNA-Vif and pcDNA-LIGHT together compared to the single immunization with plasmid pcDNA-Vif alone. Together, the results of the study suggest that candidate HIV-1 DNA vaccine can elicit HIV-1 Vif-specific immune responses in mice and that LIGHT plays the role of immunoadjuvant in co-immunization with DNA vaccine.