Transplants foster B cell alloimmunity by relaying extracellular vesicles to follicular dendritic cells.

ABSTRACT: B cells play fundamental roles in transplant rejection. However, how allogeneic (allo)-antigens (Ags) are transported from allografts to follicular dendritic cells (FDCs) in lymphoid tissues for development of B cell responses remains unknown. We demonstrated that graft allo-Ags are relayed to FDCs via small extracellular vesicles (sEVs), which activate complement via immunoglobulin M (IgM) bound to vesicle phospholipids. Complement-opsonized allo-sEVs bind splenic marginal-zone B cells that shuttle the vesicles to FDCs, which retain and recycle the allo-sEVs so they are recognized by B cells. Accordingly, graft release of allo-sEVs promoted allo-major histocompatibility complex (MHC) accumulation in FDCs, germinal center formation, Ig switch and affinity maturation, and donor-specific ant

SUBMITTER: Chen R 

PROVIDER: S-EPMC12281710 | biostudies-literature | 2025 Jun

REPOSITORIES: biostudies-literature