# Role of eosinophils during bacterial infection

> **NIH NIH R21** · STANFORD UNIVERSITY · 2023 · $195,927

## Abstract

Project Summary
Influx of eosinophils is typically associated with type II responses during allergy. More recent reports indicate
that eosinophils have essential immunoregulatory roles, as well as key anti-microbial effects against helminths,
viruses, and some bacterial species. However, the mechanisms underlying how eosinophils contribute to
eliminating bacteria are understudied, and results are diametrically different depending upon the infecting
pathogen and in acute versus chronic infection. In this application, we propose to investigate the role of
eosinophils during persistent Salmonella infection within mesenteric lymph nodes (MLNs) of 129X1/Sv/J mice.
Our unpublished data show that eosinophils, which we have localized to STm-containing granulomas, increased
significantly over the first 8 weeks of Salmonella enterica Typhimurium (STm) infection, correlated with an
increase in the eosinophil chemoattractant CCL11. In addition, depletion of eosinophils in STm-infected mice
rendered mice more susceptible to infection. Importantly, eosinophil-depleted mice had a significant reduction of
IFNγ-producing cells and lower tissue levels of IFNγ compared to IgG2 controls, suggesting that eosinophils
contribute to pathogen control by influencing the granuloma microenvironment to be Th1 skewed. Our central
hypothesis is that the functions of eosinophils within infected tissues are regulated by microenvironments, such
as the granuloma, and function to contain the pathogen during persistent infection. The impact of eosinophils on
granuloma formation and pathogen control via the production of extracellular DNA traps and possible
manipulation by bacterial virulence factors will be investigated (Aim 1). In addition, we will characterize the
immunoregulatory effector functions of eosinophils during STm persistence in the MLNs (Aim 2).

## Key facts

- **NIH application ID:** 10728101
- **Project number:** 1R21AI178663-01
- **Recipient organization:** STANFORD UNIVERSITY
- **Principal Investigator:** Denise M Monack
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2023
- **Award amount:** $195,927
- **Award type:** 1
- **Project period:** 2023-07-14 → 2025-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10728101

## Citation

> US National Institutes of Health, RePORTER application 10728101, Role of eosinophils during bacterial infection (1R21AI178663-01). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/10728101. Licensed CC0.

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