| Autor: |
Keir, Mary E., Liang, Spencer C., Guleria, Indira, Latchman, Yvette E., Qipo, Andi, Albacker, Lee A., Koulmanda, Maria, Freeman, Gordon J., Sayegh, Mohamed H., Sharpe, Arlene H. |
| Předmět: |
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| Zdroj: |
Journal of Experimental Medicine; 4/17/2006, Vol. 203 Issue 4, p883-895, 13p |
| Abstrakt: |
Programmed death 1 (PD-1), an inhibitory receptor expressed on activated lymphocytes, regulates tolerance and autoimmunity. PD-1 has two ligands: PD-1 ligand 1 (PD-L1), which is expressed broadly on hematopoietic and parenchymal cells, including pancreatic islet cells; and PD-L2, which is restricted to macrophages and dendritic cells. To investigate whether PD-L1 and PD-L2 have synergistic or unique roles in regulating T cell activation and tolerance, we generated mice lacking PD-L1 and PD-L2 (PD-L1/PD-L2-/- mice) and compared them to mice lacking either PD-L. PD-L1 and PD-L2 have overlapping functions in inhibiting interleukin-2 and interferon-γ production during T cell activation. However, PD-L1 has a unique and critical role in controlling self-reactive T cells in the pancreas. Our studies with bone marrow chimeras demonstrate that PD-L1/PD-L2 expression only on antigen-presenting cells is insufficient to prevent the early onset diabetes that develops in PD-L1/PD-L2-/- non-obese diabetic mice. PD-L1 expression in islets protects against immunopathology after transplantation of syngeneic islets into diabetic recipients. PD-L1 inhibits pathogenic self-reactive CD4+ T cell-mediated tissue destruction and effector cytokine production. These data provide evidence that PD-L1 expression on parenchymal cells rather than hematopoietic cells protects against autoimmune diabetes and point to a novel role for PD-1-PD-L1 interactions in mediating tissue tolerance. [ABSTRACT FROM AUTHOR] |
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