# STI and Implications for HIV Transmission and Prevention

> **NIH NIH R01** · EMORY UNIVERSITY · 2020 · $415,894

## Abstract

PROJECT SUMMARY
Despite making up only 2% of the US population, men who have sex with men (MSM) accounted for 67% of
new HIV infections in 2014, and incidence rates among adolescent MSM are alarmingly high in some areas.
One potential barrier to the effectiveness of biomedical HIV prevention interventions among MSM is the
physiologic efficiency of HIV transmission across the rectal mucosa, where approximately 70% of infections
are thought to occur among MSM. However, the majority of HIV mucosal transmission research has
concentrated on vaginal transmission in women and non-human primates, which is then extrapolated to
understanding the mechanisms of rectal transmission among MSM. In addition, the role of inflammation in the
rectal mucosa attributed to bacterial sexually transmitted infections (STI), including Chlamydia (CT), Gonorrhea
(GC), and syphilis, has been understudied to date despite the tremendous burden of STI in MSM and their
influence on HIV transmission. We have previously shown that rectal STI, even in the setting of routine
screening and treatment, is associated with HIV seroconversion in a cohort of HIV-negative MSM. For HIV
positive MSM, our prior work shows that rectal shedding of HIV remains low in men on suppressive
antiretroviral therapy (ART) with rectal GC and/or CT; however, sampling of the mucosa was not optimal to
detect low level shedding in this study. In the absence of rectal STI, preliminary data presented in this
application with adult HIV-negative MSM aged 18-45 show a distinct innate and adaptive pro-inflammatory
immune response to condomless receptive anal intercourse (CRAI) in the rectal mucosa, and that the diversity
and composition of the rectal mucosal microbiota differ between adult MSM who engage in CRAI versus men
who do not engage in anal intercourse (AI) with MSM engaging in CRAI being enriched for the family
Prevotellaceae. In this application, we propose to expand our rectal mucosal studies of MSM to examine the
effect of bacterial STI on the rectal mucosal resident cellular populations (aim1) and the microbiome (aim2). In
aim 3, we will study resolution of inflammation after treatment of STI and its effect on ex vivo HIV infection of
the rectal mucosa. We will build upon our successful translational mucosal immunology program with a highly
successful clinical research and retention infrastructure that was designed to understand factors that may
influence rectal transmission among MSM. A better understanding of the host response to STI in the rectum
will be useful to the design of biomedical HIV and bacterial STI prevention mechanisms, including effective
vaccines.

## Key facts

- **NIH application ID:** 9911989
- **Project number:** 5R01HD092033-04
- **Recipient organization:** EMORY UNIVERSITY
- **Principal Investigator:** Colleen F Kelley
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $415,894
- **Award type:** 5
- **Project period:** 2017-04-01 → 2022-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9911989

## Citation

> US National Institutes of Health, RePORTER application 9911989, STI and Implications for HIV Transmission and Prevention (5R01HD092033-04). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/9911989. Licensed CC0.

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