# The influence of rectal Chlamydia trachomatis infections on immunity and incident urogenital infections in women without an indication forrectal screening

> **NIH NIH R01** · INDIANA UNIVERSITY INDIANAPOLIS · 2024 · $777,815

## Abstract

ABSTRACT
Chlamydia trachomatis (Ct) infections in the U.S. are increasing and no Ct vaccine exists. Annual urogenital
tract (UGT) screening of <25 and high risk women of any age is recommended, but testing for rectal Ct infection
is not recommended in women without rectal exposure. However, rectal Ct prevalence rates are similar in women
regardless of anal sex exposures and up to 19% of Ct infections occur only in the rectum and would be missed
by screening recommendations. Animal studies suggest that rectal infection is beneficial by inducing potent
transmucosal immunity that protects the UGT against reinfection without pathological effects. It is critical that we
understand whether rectal Ct infections in women are potentially harmful, by cross-contaminating the UGT, or
beneficial, by inducing mucosal protection against UGT infection. Further, understanding if rectal Ct infections
are immunogenic will establish if a mucosal chlamydia vaccine is feasible. We will enroll women at high-risk for
chlamydia but who have never engaged in anal sex. Over 12 months, we will (1) obtain monthly oral, vaginal,
and rectal swabs to detect incident Ct infections, (2) collect quarterly blood and cervical cytobrush specimens to
study systemic and cervical T-cell responses, and (3) capture weekly sexual behavior and symptoms data to
screen for exposure and Ct-related symptoms. The goal of this project is to test the hypothesis that (1) rectal Ct
infections are frequent, long-lasting, asymptomatic, associated with specific rectal-tropic strains, and do not
increase risk for UGT infection (Aim 1) and (2) assess their influence on systemic and cervical memory T-cell
immunity and if they decrease incident UGT infections (Aim 2). By understanding if rectal Ct infections increase
or decrease UGT infection risk, these studies may change screening guidelines and lay the foundation for
development of an oral attenuated chlamydia vaccine.

## Key facts

- **NIH application ID:** 10883623
- **Project number:** 5R01AI176999-02
- **Recipient organization:** INDIANA UNIVERSITY INDIANAPOLIS
- **Principal Investigator:** Stephen J. Jordan
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $777,815
- **Award type:** 5
- **Project period:** 2023-07-06 → 2028-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10883623

## Citation

> US National Institutes of Health, RePORTER application 10883623, The influence of rectal Chlamydia trachomatis infections on immunity and incident urogenital infections in women without an indication forrectal screening (5R01AI176999-02). Retrieved via AI Analytics 2026-05-27 from https://api.ai-analytics.org/grant/nih/10883623. Licensed CC0.

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