A DNA vaccine encoding VP22 of herpes simplex virus type I (HSV-1) and OprF confers enhanced protection from Pseudomonas aeruginosa in mice.

Pseudomonas aeruginosa antimicrobial resistance is a major therapeutic challenge. DNA vaccination is an attractive approach for antigen-specific immunotherapy against P. aeruginosa. We explored the feasibility of employing Herpes simplex virus type 1 tegument protein, VP22, as a molecular tool to enhance the immunogenicity of an OprF DNA vaccine against P. aeruginosa. Recombinant DNA vaccines, pVAX1-OprF, pVAX1-OprF-VP22 (encoding a n-OprF-VP22-c fusion protein) and pVAX1-VP22-OprF (encoding a n-VP22-OprF-c fusion protein) were constructed. The humoral and cellular immune responses and immune protective effects of these DNA vaccines in mice were evaluated. In this report, we showed that vaccination with pVAX1-OprF-VP22 induced higher levels of IgG titer, T cell proliferation rate. It also provided better immune protection against the P. aeruginosa challenge when compared to that induced by pVAX1-OprF or pVAX1-VP22-OprF DNA vaccines. Molecular mechanistic analyses indicated vaccination with pVAX1-OprF-VP22 triggered immune responses characterized by a preferential increase in antigen specific IgG2a and IFN-γ in mice, indicating Th1 polarization. We concluded that VP22 is a potent stimulatory molecular tool for DNA vaccination when fused to the carboxyl end of OprF gene. Our study provides a novel strategy for prevention and treatment of P. aeruginosa infection.