Role of T-Cells in HIV CNS Reservoir Seeding, Persistence, and Neuropathogenesis (R21 Clinical Trial Not Allowed) | RFA MH 26 111

Frequently Asked Questions (FAQs)

What is this funding opportunity?

This is a National Institutes of Health (NIH) request for applications for an R21 exploratory research grant focused on how T cells contribute to HIV infection and persistence in the central nervous system (CNS), including how HIV establishes (seeds) brain reservoirs, how those reservoirs persist during effective antiretroviral therapy (ART), and how CNS immune activity may drive ongoing neuroinflammation and neurological injury.

Which NIH components are involved?

The opportunity is issued by NIH and includes the National Institute of Mental Health (NIMH) as part of the participating NIH components referenced in the description.

What is the Funding Opportunity Number?

The Funding Opportunity Number is RFA-MH-26-111.

What is the application closing date?

The closing date listed for this opportunity is March 18, 2025.

What grant mechanism is being used?

This opportunity uses the NIH R21 mechanism, which is typically intended for exploratory, early-stage, high-impact, or proof-of-concept research.

Are clinical trials allowed under this opportunity?

No. The opportunity is explicitly labeled "Clinical Trial Not Allowed," meaning applications should not propose interventional studies that prospectively assign human participants to receive an intervention.

What scientific problem is this opportunity trying to address?

The opportunity targets a major unresolved problem in HIV medicine: even when ART suppresses HIV to very low or undetectable levels in blood and provides strong virologic control, many people still experience HIV-associated CNS comorbidities and subtle neurological impairments. This suggests viral persistence and inflammatory processes in the brain can continue despite treatment.

What are the main research themes emphasized in the announcement?

The announcement emphasizes (1) how HIV reaches the CNS early after infection, (2) how HIV seeds and maintains reservoirs in the brain over time, including during effective ART, and (3) how immune activity in the CNS may contribute to persistent neuroinflammation and downstream neurological injury.

Why does the opportunity focus on T cells?

A central idea in the opportunity is that understanding CNS HIV immunology, especially the roles of different T-cell populations, is essential for advancing strategies aimed at HIV cure (sterilizing or functional) and for reducing neurological complications that remain common in the ART era.

Which T-cell populations are specifically highlighted?

The description highlights CD4 T cells and CD8 T cells. CD4 T cells are emphasized alongside monocytes as key mediators of HIV entry into the CNS and as potential long-lived sources of viral persistence. CD8 T cells are described as being heavily recruited into the CNS during acute infection, likely reflecting an effort to control local viral replication.

Does the announcement only allow T-cell-only projects?

No. While the title centers on T cells, the description makes clear that the broader CNS immune ecosystem is part of the problem space, including interactions with monocytes and inflammatory pathways, particularly in the context of persistent neuroinflammation under ART.

What does the opportunity say about how HIV enters the CNS?

It highlights that HIV reaches the CNS early after infection and that multiple immune cell types participate in both viral entry into the brain and subsequent damage.

What does the opportunity say about reservoirs in the brain?

It focuses on understanding how HIV seeds reservoirs in the brain, how those reservoirs persist over time even during effective ART, and how immune activity in the CNS may influence reservoir establishment and maintenance.

How does neuroinflammation fit into the goals of this opportunity?

The opportunity links persistent immune activity in the CNS to ongoing neuroinflammation and neurological injury, even when ART achieves strong control of HIV in blood.

How is the blood-brain barrier relevant to the research scope?

The opportunity encourages work that considers how immune surveillance, inflammation, and cell trafficking across the blood-brain barrier might influence reservoir establishment, reservoir maintenance, and consequences for brain function.

How does this opportunity relate to HIV cure strategies?

The opportunity frames CNS immunology and T-cell biology as important for advancing strategies aimed at a sterilizing cure (eliminating all replication-competent virus) or a functional cure (long-term control without ongoing therapy), and for reducing HIV-associated neurological complications.

What types of organizations are eligible to apply?

Eligibility is broad and includes many types of domestic organizations, including state, county, city/township, and special district governments; public and state-controlled institutions of higher education; private institutions of higher education; independent school districts; and public housing authorities/Indian housing authorities.

Are tribal governments and tribal organizations eligible?

Yes. Federally recognized Native American tribal governments and other Native American tribal organizations are included. The announcement also calls out Indian/Native American tribal governments that are not federally recognized as additional eligible applicants/organization types of interest or inclusion.

Are nonprofit organizations eligible?

Yes. Nonprofit organizations with or without 501(c)(3) status are included (excluding institutions of higher education within those nonprofit categories as stated in the eligibility description provided).

Are for-profit organizations eligible?

Yes. For-profit organizations other than small businesses are eligible, and small businesses are also eligible.

Are non-U.S. (foreign) organizations eligible?

Yes. The announcement calls out non-domestic (non-U.S.) entities/foreign organizations among additional eligible applicants/organization types of particular interest or inclusion.

Are community-based or faith-based organizations eligible?

Yes. Faith-based or community-based organizations are specifically called out among additional eligible applicants/organization types of interest or inclusion.

Are minority-serving institutions specifically included?

Yes. The announcement calls out Historically Black Colleges and Universities (HBCUs), Hispanic-serving Institutions, Tribally Controlled Colleges and Universities (TCCUs), Alaska Native and Native Hawaiian Serving Institutions, and Asian American Native American Pacific Islander Serving Institutions (AANAPISISs) among organization types of particular interest or inclusion.

Are U.S. territories eligible to apply?

Yes. U.S. territories or possessions are included among additional eligible applicants/organization types of interest or inclusion.

What CFDA numbers are associated with this opportunity?

The opportunity is associated with CFDA numbers 93.242, 93.279, and 93.853.

What activity areas does this opportunity fall under?

The activity areas are described as falling under health and education-related research support, consistent with NIH biomedical research priorities.

What kind of research approach fits the "Clinical Trial Not Allowed" label?

Based on the description provided, applicants should propose non-clinical-trial research approaches rather than interventional studies that prospectively assign human participants to receive an intervention.

What is the long-term impact this opportunity is aiming for?

The opportunity aims to expand and accelerate research clarifying how T-cell biology intersects with HIV persistence in the brain and ongoing CNS injury in treated infection, with longer-term goals of informing cure strategies and reducing HIV-associated neurological complications.