Immunobiology of Xenotransplantation (U19 Clinical Trial Not Allowed) | RFA AI 19 043

Opportunity Information: Apply for RFA AI 19 043

The National Institutes of Health released this grant opportunity, RFA-AI-19-043, titled "Immunobiology of Xenotransplantation (U19 Clinical Trial Not Allowed)," to build a coordinated, multi-project research effort focused on xenotransplantation immunology. The program is organized as a cooperative agreement (U19), which means awardees are expected to work in close partnership with NIH program staff and operate as part of a broader, collaborative research program rather than as fully independent investigator-initiated projects. The work supported under this announcement is strictly preclinical; clinical trials are not allowed.

At its core, the funding aims to accelerate the development and refinement of porcine-to-nonhuman primate (NHP) xenotransplantation models across several high-impact transplant targets: pancreatic islet, kidney, heart, lung, and liver. These models are intended to be realistic and rigorous testbeds that can reveal why pig grafts fail in primate recipients, what immune pathways are responsible for different patterns of rejection, and what interventions can reliably prevent rejection or promote long-term acceptance. By emphasizing pig-to-NHP studies, the FOA is targeting the translational middle ground between small-animal experiments and eventual human application, where immune barriers, physiology, and organ function can be evaluated in a way that more closely mirrors the clinical situation.

The program lays out three major scientific goals. First, it seeks to define the cellular and molecular mechanisms that drive xenograft rejection and/or enable immune tolerance. In practice, this points to deep mechanistic immunology: identifying which innate and adaptive immune cells are involved, how antibodies and complement contribute, how inflammation and coagulation pathways intersect with immunity, and what signatures distinguish rejection from stable graft function. Second, it calls for the development of effective strategies to improve xenograft survival. That includes testing immunomodulatory regimens, tolerance-induction approaches, and other interventions that can extend graft longevity and function in these demanding preclinical models. Third, it explicitly highlights the need to characterize and address physiological compatibility and limitations of xenografts, recognizing that successful xenotransplantation is not only an immune problem. Organ performance, species-specific physiological mismatches, and systemic complications that can arise even when immunologic rejection is controlled are all within scope. The long-term objective is straightforward: generate the scientific foundation and practical strategies needed to move xenotransplantation toward safe, effective clinical use.

Eligibility is broad across U.S.-based organizational types, reflecting NIH norms for biomedical research funding. Eligible applicants include public and private institutions of higher education, nonprofit organizations (with or without 501(c)(3) status), for-profit organizations (other than small businesses) as well as small businesses, and multiple levels of government entities (state, county, city/township, special district governments). It also includes independent school districts, public housing authorities/Indian housing authorities, and federally recognized tribal governments and certain tribal organizations. The FOA also calls out several categories of organizations as other eligible applicants, including 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 (AANAPISIs), along with faith-based or community-based organizations, eligible federal agencies, regional organizations, and U.S. territories or possessions.

At the same time, the opportunity is clear about restrictions related to foreign involvement. Non-domestic (non-U.S.) entities (foreign institutions) are not eligible to apply. Non-domestic components of U.S. organizations are not eligible to apply. In addition, foreign components, as defined in the NIH Grants Policy Statement, are not allowed. Taken together, those constraints mean the funded work and the participating components must be U.S.-based, with no foreign components embedded in the project structure.

From an administrative standpoint, the FOA is categorized under discretionary funding and the health funding activity area, with CFDA number 93.855. The announcement lists an award ceiling of $1,200,000 and indicates expected awards (the specific number is not provided in the text you shared). The original closing date for applications was September 16, 2019, and the FOA was created on May 30, 2019.

• The National Institutes of Health in the health sector is offering a public funding opportunity titled "Immunobiology of Xenotransplantation (U19 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 2019-05-30.
• Applicants must submit their applications by 2019-09-16. (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 $1,200,000.00 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.

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