# Macrophages and Resistance to Mycobacterium Tuberculosis Infection in Humans

> **NIH NIH K08** · UNIVERSITY OF WASHINGTON · 2022 · $190,080

## Abstract

PROJECT SUMMARY
Mycobacterium tuberculosis (Mtb) is a leading worldwide infectious killer, in part, due to a large reservoir of
latent infection that contributes to ongoing transmission. Yet some individuals resist Mtb infection despite
heavy and repeated exposure as indicated by persistently negative tuberculin skin tests (TSTs) and interferon
gamma (IFNg) release assays (IGRAs). Elucidation of the mechanisms employed by these human resisters
(RSTRs) may yield novel targets for host-directed therapies or identify immune signatures that correlate with
host protection. Dr. Simmons’s collaborators longitudinally followed a group of highly-exposed household
contacts (HHCs) of index pulmonary tuberculosis (TB) patients in Uganda and define RSTRs as the ~7% that
remain TST/IGRA-negative over 8-10 years of follow-up. Using whole transcriptome analysis (RNAseq), Dr.
Simmons found that monocyte-derived macrophages (MDMs) from RSTRs versus HHCs with latent Mtb
infection (LTBI) have distinct transcriptional responses after ex vivo Mtb infection. He further identifies a
network of genes differentially expressed in RSTR versus LTBI macrophages. Gene products of this RAB11
network play roles in intracellular phagosome or vesicle trafficking. Common polymorphisms in one of these
genes, YTHDC2, were found to associate with protection from TB disease in Uganda but the immunologic
mechanisms are unknown. The long-term objectives of this proposal are to define macrophage pathways or
genes that characterize the protective RSTR response. Dr. Simmons will determine whether RAB11 network
candidate resistant genes are required for microbicidal activities of phagosome pathways in Aim 1, and confirm
these phagosome processes are distinct in primary RSTR and LTBI macrophages. In Aim 2, he proposes
genetic approaches to identify natural variants in the RAB11 network gene YTHDC2, fine map the functional
polymorphism(s), and measure the impact that relative YTHDC2-deficiency has on phagosome maturation and
other macrophage responses to Mtb. Once the immune signatures and cellular effectors are identified in this
unique cohort of human RSTRs, host-directed therapies that augment these protective functions can be
developed to improve the efficacy of currently available antimicrobials.
Dr. Simmons is currently a Senior Fellow in the Division of Allergy and Infectious Diseases at the University of
Washington. He additionally proposes a comprehensive career development program that includes: 1)
Mentored training and formal didactics in large data set analyses (e.g. statistical genetics, systems biology); 2)
mentorship in design of case-control studies and human subjects research; 3) structured opportunities to
present his work to local and international scientific audiences; and 4) Scientific Advisory Committee meetings
that ensure scientific and career development progress. By the conclusion of this award, Dr. Simmons will
transition to an independently-funded expert in the Mtb ...

## Key facts

- **NIH application ID:** 10335176
- **Project number:** 5K08AI143926-04
- **Recipient organization:** UNIVERSITY OF WASHINGTON
- **Principal Investigator:** Jason Simmons
- **Activity code:** K08 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $190,080
- **Award type:** 5
- **Project period:** 2019-02-01 → 2024-01-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10335176

## Citation

> US National Institutes of Health, RePORTER application 10335176, Macrophages and Resistance to Mycobacterium Tuberculosis Infection in Humans (5K08AI143926-04). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10335176. Licensed CC0.

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