Federal Project Grant Award Summary

The National Institute of Allergy and Infectious Diseases (NIAID) awarded Boston Children's Hospital $267,000 under the Allergy and Infectious Diseases Research program (CFDA 93.855) on July 6, 2026, with a completion date of June 30, 2028. This R21 Project Grant funds research investigating the regulatory mechanisms of B cells in transplant alloimmunity, specifically examining whether neuropilin-2 (NRP2)-expressing B cells can suppress alloreactive T cell activation and promote immunoregulation following solid organ transplantation. The research will profile NRP2-expressing B cell populations in human and mouse models, assess their capacity to suppress CD4+ T effector cell activation, and evaluate how the NRP2 ligand semaphorin3F (SEMA3F) induces immunoregulatory differentiation in these B cell subsets.

The project addresses a critical gap in transplant immunology by characterizing rare regulatory B cell subsets that may offer protective functions superior to current immunosuppressive strategies, which have improved short-term graft survival but failed to establish durable immunoregulation and long-term graft outcomes. Deliverables include phenotypic and functional characterization of NRP2-expressing B cells, transcriptional profiling of gene responses to SEMA3F signaling, and experimental validation of the hypothesis that semaphorin-induced signaling promotes regulatory B cell differentiation and suppression of alloimmune effector responses—findings with potential translational applications to improve post-transplant immunological tolerance and graft longevity.