Induction of protective immunity against a Chlamydia trachomatis genital infection in three genetically distinct strains of mice

Abstract

To establish the feasibility of inducing a protective immune response against a chlamydial genital infection in animals with different genetic backgrounds, groups of C3H/HeN (H-2k), BALB/c (H-2d) and C57BL/6 (H-2b) mice, were immunized intranasally with elementary bodies (EB) of the Chlamydia trachomatis mouse pneumonitis biovar. Following the intranasal immunization strong Chlamydia-specific humoral and cell-mediated immune (CMI) responses were detected in the three strains of mice. Eight weeks following immunization the animals were challenged with C. trachomatis in the genital tract. Vaginal cultures showed that the three strains of mice immunized with EB were significantly protected in comparison to the sham immunized animals. To determine the ability of this immunization protocol to protect against infertility six weeks after the genital challenge the animals were mated. Mice of the three strains immunized with EB showed significant protection as demonstrated by the number of animals that were fertile, and the number of embryos present in their uterine horns, in comparison to the sham immunized mice.

Figure 1

Immunoblot of serum samples using C. trachomatis MoPn EB as the antigen performed on a 5–20% gradient SDS–PAGE. Lane 1, MW markers (×1000). Lanes 2, 3, and 4, preimmunization serum samples from C3H/HeN, C57BL/6 and BALB/c mice, respectively. Lanes 5, 6 and 7 serum samples collected 8 weeks after i.n. immunization from C3H/HeN, C57BL/6 and BALB/c mice, respectively. Lane 8, monoclonal antibodies against the 150 000 MW, the 60 000 MW crp, MOMP and the 28 000 MW proteins of the C. trachomatis MoPn serovar.