DNA vaccine encoding central conserved region of G protein induces Th1 predominant immune response and protection from RSV infection in mice

- The pVAX1/3G148-198 could induce RSV specific neutralizing antibody, Th1 biased immune response and protection from RSV infection in mice.
- This investigation focused on the immunogenicity, protective efficacy and safety in mice vaccinated by the DNA vaccine other than G polypeptide.
- It is a valuable exploration for RSV vaccine developed for sero-negative infants and the developing countries.

Human respiratory syncytial virus (RSV) can cause serious infection in the lower respiratory tract, especially in infants, young children, the elderly and the immunocompromised population worldwide. Previous study demonstrated the polypeptide (amino acids 148-198) of RSV attachment (G) glycoprotein, corresponding to the central conserved region and encompassing CX3C chemokine motif, could induce antibodies and protection from RSV challenge in mice [1,2]. In this study, we evaluated the immune efficacy of the recombinant DNA vaccine of pVAX1/3G148-198 encoding RSV G protein polypeptide. RSV specific serum IgG antibodies with neutralizing activity were stimulated following prime-boost immunization of pVAX1/3G148-198 intramuscularly, and the ratio of IgG2a/IgG1 was 4.93, indicating a Th1 biased immune response. After challenged intranasally with RSV Long, the vaccinated mice showed both decreased lung RSV titers, pulmonary inflammation and body weight loss. The results suggest that pVAX1/3G148-198 DNA vaccine may be an effective RSV vaccine candidate, and deserves further exploration.