Immunogenicity and protection against genital Chlamydia infection and its complications by a multisubunit candidate vaccine

• Published in: Journal of Microbiology, Immunology and Infection Vol. 40; no. 3; pp. 88 - 200
• Main Authors: Ifere, GO, He, Q, Igietseme, JU, Ananaba, G A, Lyn, D, Lubitz, W, Kellar, K L, Black, C M, Eko, F O
• Format: Journal Article
• Language: English
• Published: 01.06.2007
• Subjects: Chlamydia trachomatis; Vibrio cholerae
• ISSN: 1684-1182; 1365-2567

Genital infections due to Chlamydia trachomatis pose a considerable public health challenge worldwide and a vaccine is urgently needed to protect against these infections. We examined whether a vaccine composed of a combination of the major outer membrane protein (MOMP) and porin B protein (PorB) of C. trachomatis would have a protective advantage over a single subunit construct. Single and multisubunit vaccines expressing MOMP and PorB were constructed and evaluated in the mouse model of genital infection. Thus, groups of female C57BL/6 mice were immunized intramuscularly with recombinant Vibrio cholerae ghosts (VCG) expressing the vaccine antigens or VCG alone and humoral and cell-mediated immune responses were evaluated. Significant levels of Chlamydia-specific secretory immunoglobulin A and immunoglobulin G2a were detected in vaginal washes and serum of immunized mice. The multisubunit construct induced a significantly higher level of T-helper Type 1 response than the single subunits as measured by the amount of interferon-gamma produced by immune T cells in response to re-stimulation with ultraviolet-irradiated elementary bodies in vitro. Three weeks after the last immunization, animals were challenged intravaginally with 10 super(7) inclusion-forming units of C. trachomatis serovar D. There was a significant difference in the intensity and duration of vaginal shedding between the vaccine-immunized mice and controls. All the animals immunized with the multisubunit vaccine had completely resolved the infection 2 weeks post-challenge. Higher numbers of embryos were observed in vaccinated animals than in controls, indicating protection against infertility. These results underscore the potential, albeit moderate, vaccine advantage of the multisubunit formulation.