Construction of a recombinant HIV-1 gp140 protein vaccine and evaluation of its immunogenicity

Abstract

Objective To construct a recombinant HIV-1 gp140 protein vaccine and to evaluate its immunogenicity. Methods Four expression vectors containing different signal peptides including DRVI, IL-2, venom and chitinase were constructed for the expression of gp140 protein clones. Western blot assay was performed to evaluate the expression efficiency of the constructed expression vectors. The cleavage of signal peptides was analyzed by sequencing analysis. The gp140 protein clones with different lengths of C-terminus were constructed and then comparatively analyzed for the screening of optimized recombinant HIV-1 gp140 antigen. Guinea pigs were immunized with different strategies and the potency of vaccination was evaluated by detecting the binding antibodies and neutralizing antibodies after immunization. Results DRVI, the designed signal peptide, had the advantages in determining the efficiency of protein secretion and signal peptide cleavage. Compared with the co-immunization with DNA and recombinant Tiantan vaccinia (rTV) HIV vaccines, immunization of guinea pigs with the recombined gp140 protein vaccine alone could induce higher levels of binding antibodies and neutralizing antibodies. The gp140 protein with long C-terminus was slightly better than the one with short C-terminus in eliciting immune response, but no significant differences were found between them. Conclusion The optimized HIV-1 gp140 protein vaccine with appropriate protein signal peptide and C-terminus was successfully constructed and turned out to be effective in eliciting stronger immune response. Key words: HIV-1 gp140 protein; Antigen design; Immune evaluation