IFN-γ Receptor Deficient Donor T cells Mediate Protection from Graft-versus-Host Disease and Preserve Graft-versus-Tumor Responses After Allogeneic Bone Marrow Transplantation

摘要

Graft-versus-host disease (GVHD) is a major complication of allogeneic bone marrow transplantation (BMT). It has been previously reported that lung GVHD severity directly correlates with the expansion of donor Th17 cells in the absence of IFN-γ. However, the consequence of Th17-associated lung GVHD in the presence of IFN-γ has not been well-characterized. In the current study, T cells from IFN-γ receptor knockout (IFN-γR^-/-) mice, capable of producing IFN-γ but unable to signal in response to IFN-γ, have been used to further elucidate the role of IFN-γ in GVHD. We found the transfer of donor T cells from either IFN-γR^-/- or IFN-γ knockout (IFN-γ^-/-) mice resulted in significant increases in donor Th17 cells in the lung. Marked increases in IL4-producing Th2 cells infiltrating the lungs were also observed in the mice of donor IFN-γR^-/- T cells. Interestingly, despite the presence of these cells, these mice did not show the severe immune mediated histopathological lung injury observed in mice receiving donor IFN-γ^-/- T cells. Increases in lung GVHD did occur in mice with donor IFN-γR^-/- T cells when treated in vivo with anti-IFN-γ demonstrating that the cytokine has a protective role on host tissues in GVHD. A survival benefit from acute GVHD was also observed using donor cells from IFN-γR^-/-T cells compared with control donors. Importantly, tumor-bearing mice receiving IFN-γR^-/- T cells, versus wild-type donor T cells, displayed similar graft-versus tumor (GVT) effects. These results demonstrate the critical role of the IFN-γ on host tissues and cell effector functions in GVHD/GVT.