Myeloid-Derived Suppressor Cells (MDSCs) as Potential Therapeutic Targets in TB/HIV (R01 Clinical Trial Not Allowed) | PAR 19 357

Opportunity Information: Apply for PAR 19 357

This funding opportunity, titled "Myeloid-Derived Suppressor Cells (MDSCs) as Potential Therapeutic Targets in TB/HIV (R01 Clinical Trial Not Allowed)" (PAR-19-357), is an NIH discretionary grant program in the health category (CFDA 93.855) focused on understanding and therapeutically exploiting a specific immune pathway involved in tuberculosis, especially when tuberculosis occurs alongside HIV infection. The central idea is to support innovative research that clarifies how MDSCs contribute to immune suppression during Mycobacterium tuberculosis infection and how that immune suppression shapes disease progression, severity, persistence, and treatment response in people with HIV co-infection. The FOA is positioned around host-directed therapeutics, meaning strategies that modify the host immune environment rather than directly targeting the bacteria, with MDSCs being evaluated as a possible actionable target.

The scientific emphasis is on both mechanism and translation. On the mechanistic side, the announcement calls for work that deepens understanding of "host-induced immunosuppression" in TB pathogenesis, with MDSCs as a key cell population of interest. MDSCs are known in many disease settings to dampen protective immune responses; in TB and TB/HIV, that kind of suppression could plausibly reduce the immune system's ability to control bacterial replication, alter granuloma function, and affect how inflammation and tissue damage unfold. In the TB/HIV context, immune regulation is already disrupted, so the FOA encourages research that teases apart how HIV-associated immune dysfunction intersects with MDSC expansion, trafficking, activation states, and suppressive mechanisms, and how those relationships might be leveraged to improve outcomes.

On the therapeutic development side, the program invites projects that assess whether targeting MDSCs could be a viable host-directed approach for TB in the setting of HIV. This can include identifying druggable pathways used by MDSCs, testing candidate interventions in relevant experimental systems, and generating evidence that modulating MDSC activity could restore beneficial immune function without triggering harmful immunopathology. The description explicitly includes innovative clinical research as well as preclinical and non-clinical research, but the mechanism is labeled "Clinical Trial Not Allowed," which generally means the supported work should not be designed as a prospective study in which human participants are assigned to receive an intervention to evaluate its effects on health-related outcomes. In practical terms, that typically steers applicants toward laboratory studies, animal models, computational work, analyses of existing clinical samples or datasets, observational human studies without interventional assignment, and other translational activities that stop short of a clinical trial.

Administratively, this is an R01 grant mechanism, which is the NIH's standard research project grant intended to support a defined, hypothesis-driven project with clear aims and a coherent research plan. The opportunity was created on 2019-09-03, and the listed original closing date is 2022-01-10. The notice does not specify an award ceiling or the expected number of awards in the provided excerpt, so applicants would typically look to the full FOA text and NIH institute/center guidance for budget expectations, scope alignment, and any institute-specific priorities.

Eligibility is broad and includes many organization types commonly able to apply to NIH research funding. Eligible applicants include state, county, city, and township governments; special district governments; independent school districts; public and state-controlled institutions of higher education; private institutions of higher education; federally recognized Native American tribal governments; tribal organizations (including those other than federally recognized governments); public housing authorities and Indian housing authorities; nonprofits with or without 501(c)(3) status (other than institutions of higher education); for-profit organizations (other than small businesses); small businesses; and other entities. The FOA also highlights additional eligible applicant categories such as Alaska Native and Native Hawaiian Serving Institutions, Asian American Native American Pacific Islander Serving Institutions (AANAPISIs), Hispanic-serving Institutions, Historically Black Colleges and Universities (HBCUs), Tribally Controlled Colleges and Universities (TCCUs), faith-based or community-based organizations, eligible federal agencies, regional organizations, U.S. territories or possessions, and non-domestic (non-U.S.) entities and foreign organizations. This wide eligibility signals an intent to encourage participation from diverse institutions and geographies, including settings where TB/HIV burden is high and where access to relevant cohorts, specimens, and local expertise can meaningfully strengthen the science.

Overall, the opportunity is aimed at advancing a clearer, actionable picture of how MDSCs shape immune suppression in TB/HIV and whether intervening on these cells or their pathways could complement existing TB therapies. The expected output is not just descriptive immunology, but research that points toward practical host-directed strategies, supported by rigorous preclinical evidence and clinically relevant human immunology, while remaining outside the boundaries of an NIH-defined clinical trial.

• The National Institutes of Health in the health sector is offering a public funding opportunity titled "Myeloid-Derived Suppressor Cells (MDSCs) as Potential Therapeutic Targets in TB/HIV (R01 Clinical Trial Not Allowed)" and is now available to receive applicants.
• Interested and eligible applicants and submit their applications by referencing the CFDA number(s): 93.855.
• This funding opportunity was created on 2019-09-03.
• Applicants must submit their applications by 2022-01-10. (Agency may still review applications by suitable applicants for the remaining/unused allocated funding in 2026.)
• Eligible applicants include: State governments, County governments, City or township governments, Special district governments, Independent school districts, Public and State controlled institutions of higher education, Native American tribal governments (Federally recognized), Public housing authorities/Indian housing authorities, Native American tribal organizations (other than Federally recognized tribal governments), Nonprofits having a 501 (c) (3) status with the IRS, other than institutions of higher education, Nonprofits that do not have a 501 (c) (3) status with the IRS, other than institutions of higher education, Private institutions of higher education, For-profit organizations other than small businesses, Small businesses, Others.

Apply for PAR 19 357

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