# Developing a mouse model to examine the specific impact of IFNa in the pathogenesis of genital tract Chlamydia infection

> **NIH NIH R03** · MARIAN UNIVERSITY · 2020 · $67,580

## Abstract

Reproductive tract pathology caused by Chlamydia infections is the result of the immune responses to the presence of
Chlamydia within the female reproductive tract. Both innate and adaptive immune responses are induced as part of the host
defense against infection, and specific cytokines and chemokines play a role in regulating these defense mechanisms.
Because our previously published data show that TLR3 deficiency leads to a significant decrease in the synthesis of IFN-β
during C. muridarum (Cm) infection in OE cells and mice, we hypothesized that IFN-β was likely not a contributing factor
to the increased amount of genital tract pathology seen in the TLR3-deficient mice. We further hypothesized that IFN-β
was instead a necessary component of the protective immune response to Cm infection. To test these hypotheses, we
infected both wild-type and IFN-β KO mice intravaginally with 105 IFU Cm and our preliminary show that IFN-β KO mice
had higher chlamydial loads and suffered more genital tract pathology during Cm infection when compared to WT mice.
Our data challenge the paradigm that type-1 IFNs are detrimental in the host response to Chlamydia infection that was
established by other investigators using interferon α/β receptor (IFNAR) KO mice. However, one of the exciting outcomes
of our in vitro investigations into the mechanisms of the Chlamydia-TLR3 interaction was that TLR3-deficiency leads to
an overexpression of several IFNα subtypes. This unexpected finding reveals that TLR3 differentially regulates IFNα and
IFN-β, whereby it stimulates the induction of IFN-β during Cm infection in OE cells, while simultaneously down-regulating
the expression of IFNα. The over-expression of IFNα during TLR3 deficiency implicates IFNα (and not IFN-β) as a possible
contributor to the increased genital tract pathology seen in TLR3-deficient mice and would support the narrative of a type-
1 IFN exacerbating the Chlamydia-caused genital tract pathology reported by others using IFNAR KO mice. The research
plan for Specific Aim #1 describes using CRISPR-Cas9 to generate an inbred knock-out mouse strain that is deficient in the
gene expression and protein function of IFNα subtypes 2, 4, 12, and 13. Because these four subtypes of IFNα represent the
only IFNα subtypes induced during Cm infection of murine genital tract epithelium, this quadruple KO mouse will be an
important reagent for us to test the hypothesis that IFNα contributes to reproductive tract pathology during Cm infection
both in vitro and in vivo.

## Key facts

- **NIH application ID:** 10041346
- **Project number:** 1R03AI154033-01
- **Recipient organization:** MARIAN UNIVERSITY
- **Principal Investigator:** WILBERT A DERBIGNY
- **Activity code:** R03 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $67,580
- **Award type:** 1
- **Project period:** 2020-08-19 → 2023-07-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10041346

## Citation

> US National Institutes of Health, RePORTER application 10041346, Developing a mouse model to examine the specific impact of IFNa in the pathogenesis of genital tract Chlamydia infection (1R03AI154033-01). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10041346. Licensed CC0.

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