Vaccination with MIP or Pgp3 induces cross-serovar protection against chlamydial genital tract infection in mice.

Previously we reported that recombinant Chlamydia muridarum macrophage infectivity potentiator (MIP) provided partial protection against C. muridarum genital tract infection in mice. On the other hand, Chlamydia trachomatis plasmid encoded Pgp3could induce the protection against C. muridarum air way infection. This study aimed to evaluate the immunogenicity of MIP and Pgp3 from C. trachomatis serovar D and further investigate whether MIP and Pgp3 provide cross-serovar protection against C. muridarum genital tract infection in mice. Our results showed that vaccination by any regimen, including MIP alone, Pgp3 alone or MIP plus Pgp3, induced specific serum antibody production and Th1-dominant cellular responses in mice. Live chlamydial shedding from the vaginal and inflammatory pathologies in the oviduct markedly reduced. However, MIP + Pgp3 vaccination did not provide better protection than the single immunization. In conclusion, this study demonstrated that both MIP and Pgp3 can induce cross-serovar protective against chlamydial genital tract infection, and provided the guide for the development of optimal multisubunit vaccines against C. trachomatis infection.