# Determining the role of the vaginal microbiota in microbial and immunological resistance to vaginal pathobiont colonization

> **NIH NIH F31** · BAYLOR COLLEGE OF MEDICINE · 2022 · $46,752

## Abstract

Disturbances of the human vaginal microbiota can cause severe complications for women and, if pregnant, their
neonates. Currently, about one in four women experience vaginal dysbiosis, a condition marked by the absence
of the health-associated genus Lactobacillus and the presence of a heterogenous consortium of microbes.
Although clinical studies have found associations between Lactobacillus dominant vaginal communities and
reduced vaginal infection, the complexity of the role that vaginal microbiota play in the protection against
pathobiont outgrowth has not been thoroughly studied. Without an understanding of protective microbial and
host factors leading into vaginal dysbiosis, antibiotic therapeutics targeting the symptomatic influx of other taxa
have not been effective in preventing the recurrence of infection. Thus, it is necessary to define the initial factors
that increase susceptibility to vaginal infection. The overarching goal of this proposal is to understand the
capacity at which the vaginal microbiota can directly confer protection against pathobiont outgrowth or indirectly
alter the local immune response to inhibit pathobiont colonization. To attribute a reduction of pathobiont
colonization to local factors, we will delineate whether the vaginal microbiota or immune profile are shaped by
microbial and immunological processes in the gut. We hypothesize that endogenous vaginal microbiota are
sufficient to determine susceptibility to pathobiont colonization and shape the local immune profile both
in homeostasis and in vaginal dysbiosis. To understand both the vaginal microbiota’s influence on the
transition to the susceptible state of vaginal dysbiosis and the ability to enhance immunological protection against
pathobiont outgrowth, we will interrogate in vivo and in vitro models. Specifically, we will determine the microbe
and immune factors that mediate protection against vaginal dysbiosis-associated pathobionts Group B
Streptococcus and Prevotella bivia by utilization of the HMbmice model, which reflects a humanized vaginal tract
dominated by Lactobacillus spp. We will describe the vaginal microbiota of HMbmice to understand the community
dynamics and compositions through longitudinal 16S rRNA gene sequencing. We will then employ mini-
bioreactors to cultivate vaginal microbes in vitro, testing for specific bacteria and metabolites that are capable of
limiting vaginal infection. Additionally, we will utilize flow cytometry to elucidate the impact that different vaginal
microbiota have on training of the local immune function. Lastly, we will generate gnotobiotic mice to resolve
whether the vaginal microbiota and immune system are influenced by the gut, establishing the source of vaginal
susceptibility to infection. Ultimately, this proposal seeks to benefit underrepresented groups in science through
the therapeutic discoveries for women’s health and the training of the applicant, who will focus on disseminating
scientific knowledge ...

## Key facts

- **NIH application ID:** 10536287
- **Project number:** 1F31AI167538-01A1
- **Recipient organization:** BAYLOR COLLEGE OF MEDICINE
- **Principal Investigator:** Marlyd Elizabeth Mejia
- **Activity code:** F31 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $46,752
- **Award type:** 1
- **Project period:** 2022-08-26 → 2025-08-25

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10536287

## Citation

> US National Institutes of Health, RePORTER application 10536287, Determining the role of the vaginal microbiota in microbial and immunological resistance to vaginal pathobiont colonization (1F31AI167538-01A1). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/10536287. Licensed CC0.

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