Although T-cell CD28/CD40 costimulation blockade represents a powerful mechanism to
promote immune tolerance during murine allotransplantation, it has not yet been
successfully translated to clinical transplantation. We determined the impact of natural killer
(NK) cells on costimulation blockade-resistant rejection of donor bone marrow. We found
that NK cells represent a potent barrier to engraftment: host NK depletion led to increased
donor stem cell survival, increased mixed hematopoietic chimerism and to engraftment of …