In Vitro and Animal Model Studies on HBV/HIV Co-Infection (R21) | PA 17 281

Opportunity Information: Apply for PA 17 281

The In Vitro and Animal Model Studies on HBV/HIV Co-Infection (R21) funding opportunity (PA 17 281) is a discretionary National Institutes of Health (NIH) grant designed to push the field forward in two tightly connected areas: building better experimental models of hepatitis B virus (HBV) and human immunodeficiency virus (HIV) co-infection, and using those models to clarify how the two viruses interact in ways that shape disease. The central idea is that progress in HBV/HIV co-infection has been limited by a lack of robust laboratory systems that realistically mimic what happens in people, which in turn slows down both basic discovery and practical drug development. This FOA is meant to stimulate new approaches that can shorten the path from laboratory insight to therapies that are safer and more effective for co-infected individuals.

A major emphasis of the FOA is the development of novel in vitro systems and small animal models that can reproduce key features of HBV/HIV co-infection. In vitro systems can include advanced cell culture approaches that better reflect human liver biology and immune interactions, while small animal models are intended to provide a living system where viral replication, immune responses, and tissue damage can be studied over time. The purpose of investing in these platforms is not model-building for its own sake, but rather enabling faster and more reliable screening, evaluation, and optimization of candidate drugs and therapeutic strategies specifically in the context of co-infection. This is important because drug behavior, toxicity, viral dynamics, and immune effects can differ meaningfully when both viruses are present, and findings from single-infection studies do not always translate cleanly.

The second major goal is to improve understanding of immunopathogenic interactions between HBV and HIV, meaning how the immune system responds to each virus and how those responses influence disease severity, persistence, and progression when the infections occur together. Co-infection can alter immune function, inflammation, and liver injury pathways, and the FOA encourages research that can tease apart these mechanisms in ways that are experimentally tractable and clinically relevant. By supporting studies that connect model development with mechanistic immunology, the program aims to generate insights that can inform not only drug discovery, but also broader therapeutic strategies, such as immune-based interventions and approaches to reduce liver-related complications.

This opportunity uses the NIH R21 mechanism, which generally supports exploratory and developmental research intended to test novel concepts, generate preliminary data, and open up new directions that may be too early-stage for larger awards. The listed award ceiling is $200,000, reflecting a focus on proof-of-concept work, early validation of platforms, and targeted mechanistic questions that can establish feasibility and justify future expansion. The original closing date provided for this specific listing was January 7, 2019, and the FOA was created on May 12, 2017, indicating it was issued to catalyze near-term innovation in this niche but high-impact research area.

Eligibility is broad, reflecting an intent to draw in diverse institutional strengths, including academic labs, nonprofits, government entities, and industry. Eligible applicants include state, county, and local governments; special districts; 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 and Indian housing authorities; nonprofits with and without 501(c)(3) status (excluding higher education institutions in those nonprofit categories as specified); for-profit organizations other than small businesses; small businesses; and other organizations. The FOA also explicitly highlights additional eligible applicant types such as Alaska Native and Native Hawaiian Serving Institutions, Asian American Native American Pacific Islander Serving Institutions (AANAPISISs), 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 entities (foreign organizations). That breadth suggests NIH was seeking to encourage participation from a wide range of communities and research environments, including groups that may offer unique patient populations, specialized model-building expertise, or innovative translational capabilities.

In terms of classification, the FOA is a grant under the broader activity areas of education and health, and it is associated with multiple CFDA numbers (93.273, 93.393, 93.394, 93.395, 93.396, 93.399, 93.855, 93.856), reflecting how NIH initiatives can span several institutes and program lines related to infectious diseases, immunology, and associated biomedical research priorities. Overall, the opportunity is best understood as a targeted push to overcome technical bottlenecks in HBV/HIV co-infection research by funding early-stage, high-value model systems and the mechanistic studies those systems make possible, with the downstream goal of accelerating therapeutic discovery and improving outcomes for people living with both infections.

• The National Institutes of Health in the education, health sector is offering a public funding opportunity titled "In Vitro and Animal Model Studies on HBV/HIV Co-Infection (R21)" and is now available to receive applicants.
• Interested and eligible applicants and submit their applications by referencing the CFDA number(s): 93.273, 93.393, 93.394, 93.395, 93.396, 93.399, 93.855, 93.856.
• This funding opportunity was created on 2017-05-12.
• Applicants must submit their applications by 2019-01-07. (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 PA 17 281

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