# Streptococcus pyogenes manipulates host immunity via the Rgg2/3 quorum sensing system

> **NIH NIH F31** · UNIVERSITY OF ILLINOIS AT CHICAGO · 2021 · $51,036

## Abstract

ABSTRACT
Group A Streptococcus (GAS) is an obligate human pathogen that causes 600 million infections annually,
ranging from superficial to severe and invasive. Interestingly, GAS can also asymptomatically colonize up to
30% of children. Because the reservoir for this bacterium is exclusively humans, a better understanding of
mechanisms promoting the asymptomatic lifestyle of GAS can help control the persistence of this ubiquitous
bacterium in the population. Like many other bacterial species, GAS utilizes chemical communication, or quorum
sensing (QS) systems, to genetically coordinate behaviors across a population. Our lab has characterized the
Rgg2/3 QS system and has shown that it promotes phenotypes indicative of cell surface alterations, including
lysozyme resistance and biofilm formation. Our preliminary experiments show that Rgg2/3 activation also alters
the host response in vitro, resulting in decreased macrophage pro-inflammatory cytokine responses, and in vivo,
resulting in prolonged mouse nasopharyngeal colonization. This proposal seeks to test the hypothesis that GAS
utilizes Rgg2/3 QS-mediated modifications to alter interactions with the host. We will examine the implications
of these modifications on the adaptive and innate immune responses to GAS, and we will determine what altered
GAS surface molecules contribute to this modulation. Understanding the role of QS in manipulating immune
responses will provide additional support for developing future strategies to combat infection.

## Key facts

- **NIH application ID:** 10212919
- **Project number:** 5F31AI147429-03
- **Recipient organization:** UNIVERSITY OF ILLINOIS AT CHICAGO
- **Principal Investigator:** KATE M RAHBARI
- **Activity code:** F31 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $51,036
- **Award type:** 5
- **Project period:** 2019-08-16 → 2022-08-15

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10212919

## Citation

> US National Institutes of Health, RePORTER application 10212919, Streptococcus pyogenes manipulates host immunity via the Rgg2/3 quorum sensing system (5F31AI147429-03). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10212919. Licensed CC0.

---

*[NIH grants dataset](/datasets/nih-grants) · CC0 1.0*