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Updated: Jun 8, 2026
Urinary Tract Infection in a Small Animal Model: Transurethral Catheterization of Male and Female Mice
Published on: December 1, 2017
A new murine model for testing vaccines against genital Chlamydia trachomatis infections in males
Sukumar Pal1, Annahita K Sarcon, Luis M de la Maza
1Department of Pathology and Laboratory Medicine, Medical Sciences, Room D440, University of California, Irvine, Irvine, CA 92697-4800, USA.
Abstract:
Two groups of 50 BALB/c male mice were immunized with live Chlamydia trachomatis mouse pneumonitis (MoPn) using the intranasal (i.n.) or the meatus urethra (intraurethral: i.u.) routes. As a control group, 100 male mice were sham-immunized in parallel. Both groups of animals vaccinated with live organisms developed strong Chlamydia-specific humoral and cell mediated immune responses. Based on the IgG2a/IgG1 ratio and the levels of IFN-γ both groups mounted a Th1 immune response. At six weeks following the immunization, all mice were challenged in the meatus urethra. The urethra, urinary bladder, testes and epididymides were harvested at weekly intervals and tested for the presence of C. trachomatis. Based on the culture results from these four organs both groups of Chlamydia-immunized mice showed significant protection. In the group immunized i.u., 10% (5/50) had positive cultures, while in the group immunized i.n. 28% (14/50) had positive cultures during the 5 weeks of observation. In contrast, in the sham-immunized animals 47% (47/100) had positive cultures (P<0.005) during the study period. In addition, the number of positive organs, the length of time that the animal had positive cultures, and the total number of inclusion forming units (IFU) recovered were overall significantly lower in the i.u. or i.n. groups in comparison with the sham-immunized animals. However, in relation to the i.u. immunized group, the protection elicited in the i.n. group was delayed and not as robust. In conclusion, immunization of mice in the meatus urethra may provide the gold standard for testing Chlamydia vaccines in a male model.
Insights
Intraurethral immunization with live Chlamydia trachomatis (MoPn) induced strong protective immunity in male mice. This route offers a potential gold standard for evaluating new Chlamydia vaccines.
Area of Science:
- Immunology
- Microbiology
- Vaccinology
Background:
- Chlamydia trachomatis infections pose significant health challenges.
- Developing effective vaccines against Chlamydia is a critical public health goal.
- Understanding immune responses to Chlamydia in male reproductive tract models is essential.
Purpose of the Study:
- To compare the efficacy of intranasal (i.n.) versus intraurethral (i.u.) immunization routes for Chlamydia trachomatis (MoPn) in a male mouse model.
- To evaluate the resulting humoral and cell-mediated immune responses.
- To assess protection against subsequent urethral challenge.
Main Methods:
- BALB/c male mice were immunized intranasally or intraurethrally with live C. trachomatis MoPn.
- Control groups received sham immunization.
- Mice were challenged intraurethrally six weeks post-immunization.
- Urethra, urinary bladder, testes, and epididymides were cultured weekly for C. trachomatis.
- Humoral and cell-mediated immunity (IFN-γ, IgG2a/IgG1 ratio) were assessed.
Main Results:
- Both i.n. and i.u. immunization induced strong Th1-biased immune responses.
- Immunized groups showed significant protection against urethral challenge compared to controls (10-28% positive cultures vs. 47%).
- Intraurethral immunization provided more robust and timely protection than intranasal immunization.
Conclusions:
- Intraurethral immunization with live C. trachomatis MoPn is a highly effective strategy for inducing protective immunity in male mice.
- This model, particularly the i.u. route, may serve as a gold standard for Chlamydia vaccine development.
- Further research into i.u. vaccination strategies is warranted for controlling Chlamydia infections.
