Summary
This NIH funding opportunity announcement (PAR-25-362) solicits R01 research grant applications focused on early immune system development and ontogeny. Clinical trials are optional under this mechanism. The opportunity is issued by the National Institutes of Health (HHS) and remains open for an extended multi-year period, reflecting a standing program announcement rather than a single-award contract. Applicants are expected to propose investigator-initiated research projects advancing understanding of how the immune system develops in early life.