Immunogenicity comparison of DNA vaccines encoding HIY-1 AE2f Tat, Rev and Nef in different gene fusion formulations

Abstract

Objective To construct DNA vaccine expressing HIV-1 AE2f gp145-tat-rev-nef fusion gene( AE-Gp145TRN) and to compare the immunogenicities of DNA vaccines expressing Tat, Rev and Nef in gene fusion formulations of tat-rev-integrase(c-half)-vif-nef( AE-TRIVN) and AE-Gpl45TRN. Methods DNA vaccine was constructed by inserting the codon optimized HIV-1 AE2( gp145-tat-rev-nef fusion gene into mammalian expression DNA vector. In vitro expression efficiency of the constructed DNA vaccine was determined by Western blot and the immunogenicities of AE-Gpl45TRN and AE-TRIVN were compared by immunizing female BALB/c mice. IFN-r ELISPOT assay was used to read out the specific T cell immunity. Results Western blot assay showed the constructed DNA vaccine could be expressed efficiently in vitro. After vaccination, AE-TRIVN mounted significantly higher T cell responses against Tat, Rev and Nef[(148±91)SFCs/106 splenocytes]than Gpl45TRN[(55±28) SFCs/106 splenocytes]. Specific T cell responses elicited by AE-TRIVN predominantly targeting Rev, whereas Gpl45TRN could significantly enhance T cell responses against Nef. Conclusion AE-TRIVN and Gpl45TRN induced distinct T cell response modalities, which implied different gene fusion formulations may affect the immunogenicity of specific DNA vaccines. Key words: HIV/AIDS; Vaccine; T cell; Regulatory/accessory protein; Fusion antigen