Myeloid-Derived Suppressor Cells (MDSCs) as Potential Therapeutic Targets in TB/HIV (R21 Clinical Trial Not Allowed) | PAR 19 364

Opportunity Information: Apply for PAR 19 364

The grant opportunity titled "Myeloid-Derived Suppressor Cells (MDSCs) as Potential Therapeutic Targets in TB/HIV (R21 Clinical Trial Not Allowed)" (Funding Opportunity Number PAR-19-364) is a National Institutes of Health (NIH) discretionary grant program focused on early-stage, innovative research that looks at how myeloid-derived suppressor cells influence tuberculosis (TB) disease, especially when TB occurs alongside HIV infection. The central idea behind the announcement is that TB outcomes are not driven only by the bacteria (Mycobacterium tuberculosis), but also by host immune responses that can become suppressive or dysregulated. MDSCs are a key candidate cell population in this space because they can dampen immune activity, potentially allowing TB to persist, worsen, or reactivate. This FOA aims to support projects that clarify whether MDSCs could be intentionally targeted as part of host-directed therapy, meaning treatments that improve disease outcomes by adjusting the patient immune environment rather than directly attacking the pathogen.

The scientific scope explicitly welcomes both clinical research and preclinical/non-clinical studies, but it draws a firm line that clinical trials are not allowed under this announcement. In practice, that generally means applicants can propose studies involving human samples, observational clinical investigations, mechanistic analyses, or small-scale clinical research activities that do not test an intervention for efficacy in a trial framework. On the preclinical side, applicants can propose laboratory, animal model, or translational experiments designed to uncover mechanisms of MDSC expansion or function during TB and HIV co-infection, to map how MDSCs suppress protective immune responses, and to identify pathways that might be modulated therapeutically. A major emphasis is placed on understanding host-induced immunosuppression and how it contributes to TB pathogenesis, including progression from latent infection to active disease, severity of disease, and impaired immune control in the setting of HIV.

This opportunity uses the NIH R21 funding mechanism, which is commonly intended for exploratory and developmental research. R21 awards are typically used to support high-risk, high-reward concepts, proof-of-concept studies, development of new approaches or models, and generation of preliminary data that could later justify a larger project. The listed award ceiling is $200,000, aligning with the smaller, early-stage nature of an R21. The funding activity category is Health, and the CFDA number associated with this opportunity is 93.855. The original closing date provided for the opportunity was January 10, 2022, and the FOA creation date was September 3, 2019.

Eligibility is broad and includes a wide range of domestic U.S. organizational types: state, county, city or 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 that are not federally recognized; public housing authorities/Indian housing authorities; nonprofit organizations with or without 501(c)(3) status (when not part of an institution of higher education); for-profit organizations (other than small businesses); and small businesses. In addition, the FOA highlights expanded categories of "other eligible applicants," reinforcing participation from organizations that serve historically underrepresented or specifically designated communities and regions. These include 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, U.S. territories or possessions, and non-U.S. entities (foreign organizations) as well as regional organizations. This broad eligibility structure signals an intent to encourage diverse institutional participation, including organizations with strong community or regional ties to populations most affected by TB and HIV.

Overall, PAR-19-364 is aimed at advancing the science needed to determine whether MDSCs are a practical and meaningful therapeutic target for improving TB outcomes in people living with HIV, while also deepening understanding of immune suppression as a driver of TB disease progression. Projects responding to this FOA would be expected to bring forward new mechanistic insights, identify actionable immune pathways, or generate convincing early evidence that modulating MDSCs could complement existing TB treatments, particularly in the complex immune landscape created by HIV co-infection.

• 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 (R21 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.)
• Each selected applicant is eligible to receive up to $200,000.00 in funding.
• 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 19 364

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