Host anti-donor T-cell receptor (TCR) (Host anti-donor TCR)

Host anti-donor T cells are a specific population of recipient immune cells that recognize donor antigens, leading to transplant rejection or host-versus-graft disease (HvGD). The interaction between these host T cells and "veto cells" (typically donor-derived CD8+ T cells or hematopoietic stem cells) is a specialized mechanism of immune tolerance. When the host T-cell receptor (TCR) recognizes Major Histocompatibility Complex (MHC) class I molecules on the veto cell, the veto cell actively induces apoptosis or anergy in the host T cell (Reisner & Martelli, 2005, Nature Reviews Immunology). This "veto effect" is unique because it specifically eliminates only the clones of T cells capable of rejecting the graft, while leaving the rest of the host's immune repertoire intact (Bachar-Lustig et al., 2002, Immunology Reviews). Therapeutic strategies leveraging this mechanism involve the administration of donor-derived veto cells to facilitate engraftment and reduce the need for global immunosuppression in bone marrow or organ transplantation (Reisner et al., 2011, Trends in Immunology). The primary molecular interface for this effect is the host TCR binding to the donor MHC-I, which subsequently triggers death signals such as the Fas/FasL pathway within the host cell (Verneris et al., 2002, Current Opinion in Hematology).

Other names

Host anti-donor T cellsAlloreactive host T cellsHost-versus-graft T cellsVeto-targeted T cells

Induction of apoptosis in host alloreactive T cells via TCR-mediated recognition of donor MHC class I on veto cells.