摘要：We reported that intranasal immunization of mice with recombinant major outer membrane protein (MOMP) of Chlamydia trachomatis genetically fused with modified cholera toxin elicited mucosal and systemic antibody responses, but with inefficient protective mechanisms for complete protection of mice against a homologous C. trachomtis challenged infection. To begin to identify specific immunogenic MOMP regions to pursue as vaccine candidates, herein we selected small gene fragments of the MOMP gene containing T-cell epitopes (278-370 aa) and generated a rMOMP peptide (rMOMP-278). rMOMP and rMOMP-278 proteins were cloned, expressed, and their purities and specificities confirmed by SDS-PAGE and Western blot, respectively. We tested the immunogenicity of rMOMP-278 as compared to the parent rMOMP in mice. Mice were immunized intramuscularly with purified rMOMP proteins; total- and isotype- (IgA, IgG1, IgG2a, and IgG2b) specific antibodies in sera and vaginal washes were measured by ELISA. Immunized mice developed antigen-specific total antibodies in a kinetic fashion, with responses being higher to rMOMP than rMOMP- 278. However, antigen-specific isotype antibodies were detected in the order of IgG2b > IgG2a > IgG1 for rMOMP- 278, indicating more of a mixed Th1/Th2 response. Contrastingly, antibody responses to rMOMP was more of a predominant Th2 response in the order of IgG1 > IgG2b > IgG2a. Our data are evidence to suggest that rMOMP-278 is immunogenic by its ability to evoke systemic and mucosal immune responses with a Th1 bias in mice, and therefore may be an attractive peptide alternative to full MOMP as a vaccine candidate against C. trachomatis genital tract infection.
