Suppression of Chlamydial Pathogenicity by Nonspecific CD8+ T Lymphocytes

ABSTRACT Chlamydia trachomatis, a leading infectious cause of tubal infertility, induces upper genital tract pathology, such as hydrosalpinx, which can be modeled with Chlamydia muridarum infection in mice. Following C. muridarum inoculation, wild-type mice develop robust hydrosalpinx, but OT1 mice fail to do so because their T cell receptors are engineered to recognize a single ovalbumin epitope (OVA457-462). These observations have demonstrated a critical role of Chlamydia-specific T cells in chlamydial pathogenicity. In the current study, we have also found that OT1 mice can actively inhibit chlamydial pathogenicity. First, depletion of CD8+ T cells from OT1 mice led to the induction of significant hydrosalpinx by Chlamydia, indicating that CD8+ T cells are necessary to inhibit chlamydial pathogenicity. Second, adoptive transfer of CD8+ T cells from OT1 mice to CD8 knockout mice significantly reduced chlamydial induction of hydrosalpinx, demonstrating that OT1 CD8+ T cells are sufficient for attenuating chlamydial pathogenicity in CD8 knockout mice. Finally, CD8+ T cells from OT1 mice also significantly inhibited hydrosalpinx development in wild-type mice following an intravaginal inoculation with Chlamydia. Since T cells in OT1 mice are engineered to recognize only the OVA457-462 epitope, the above observations have demonstrated a chlamydial antigen-independent immune mechanism for regulating chlamydial pathogenicity. Further characterization of this mechanism may provide information for developing strategies to reduce infertility-causing pathology induced by infections.

Comparison of cervico-vaginal colonization among sexually active women by intrauterine device use

Introduction: In this study we aimed to evaluate the effect of intrauterine devices (IUDs) on cervico-vaginal colonization. Methodology: Cervico-vaginal samples of 96 patients with vaginal discharge were included in the study. Microscopic evaluation, bacteriological and fungal culture, and antigen testing for Chlamydia trachomatis using an immunochromatographic test method were performed. Results: Trichomonas vaginalis was not detected by wet mount examination. Gram smear revealed that seven patients (7.3%) had Candida spp. and five (5.2%) had clue cell. Of the 96 swabs tested for conventional culture, pathogenic microorganisms were isolated from 24 patients. While Neisseria gonorrhoeae was not found in any of the sample, five (5.2%) were positive for Gardnerella vaginalis. Five (5.2%) were positive for C. trachomatis antigen, while three positivity only for C. trachomatis antigen, one had G. vaginalis additionally, and the other had a mixed infection. Chlamydial antigen positivity was higher among women over 30 years of age (p = 0.157). Increase in polymorphonuclear leukocytes (PNL) was detected 40% and 35.2% of samples, positive and negative, for chlamydial antigen, respectively (p= 1.000). Among IUD+ cases, increase in PNL, fungal elements, E. coli and Gram-positive bacteria and decrease in Lactobacillus spp. were observed, compared to IUD-cases. No statistically significant relationship was detected between IUD and chlamydial antigen with the reported rates of 4.8% and 5.6% for IUD+ or IUD-, respectively (p > 0.05). Conclusion: Statistically significant relationship was not detected between IUD and cervico-vaginal colonization. More comprehensive studies using specific test methods should be conducted to better understand the relationship.