title: A critical role of IFNgamma in priming MSC-mediated suppression of T cell proliferation through up-regulation of B7-H1.
abstract: Bone-marrow-derived mesenchymal stem cells (MSCs) have been shown to possess immunosuppressive properties, e.g., by inhibiting T cell proliferation. Activated T cells can also enhance the immunosuppression ability of MSCs. The precise mechanisms underlying MSC-mediated immunosuppression remain largely undefined, although both cell-cell contact and soluble factors have been implicated; nor is it clear how the immunosuppressive property of MSCs is modulated by T cells. Using MSCs isolated from mouse bone marrow, we show here that interferon gamma (IFNgamma), a well-known proinflammatory cytokine produced by activated T cells, plays an important role in priming the immunosuppressive property of MSCs. Mechanistically, IFNgamma acts directly on MSCs and leads to up-regulation of B7-H1, an inhibitory surface molecule in these stem cells. MSCs primed by activated T cells derived from IFNgamma-/- mouse exhibited dramatically reduced ability to suppress T cell proliferation, a defect that can be rescued by supplying exogenous IFNgamma. Moreover, siRNA-mediated knockdown of B7-H1 in MSCs abolished immunosuppression by these cells. Taken together, our results suggest that IFNgamma plays a critical role in triggering the immunosuppresion by MSCs through up-regulating B7-H1 in these cells, and provide evidence supporting the cell-cell contact mechanism in MSC-mediated immunosuppression.
authors.affiliation: Shanghai Institute of Immunology, Shanghai 200025, China.
authors.forename: Huiming
authors.initials: H
authors.lastname: Sheng
authors.forename: Ying
authors.initials: Y
authors.lastname: Wang
authors.forename: Yuqing
authors.initials: Y
authors.lastname: Jin
authors.forename: Qiuyu
authors.initials: Q
authors.lastname: Zhang
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhang
authors.forename: Li
authors.initials: L
authors.lastname: Wang
authors.forename: Baihua
authors.initials: B
authors.lastname: Shen
authors.forename: Shuo
authors.initials: S
authors.lastname: Yin
authors.forename: Wei
authors.initials: W
authors.lastname: Liu
authors.forename: Lei
authors.initials: L
authors.lastname: Cui
authors.forename: Ningli
authors.initials: N
authors.lastname: Li
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000276:immunology*; D060890:B7-H1 Antigen; D001854:Bone Marrow Cells / Q000276:immunology*; D049109:Cell Proliferation; D002478:Cells, Cultured; D015536:Down-Regulation / Q000235:genetics; D005260:Female; D007108:Immune Tolerance / Q000276:immunology*; D007371:Interferon-gamma / Q000235:genetics / Q000502:physiology*; D008213:Lymphocyte Activation / Q000276:immunology; D059630:Mesenchymal Stem Cells / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D034622:RNA Interference / Q000502:physiology; D034741:RNA, Small Interfering / Q000235:genetics; D013601:T-Lymphocytes / Q000276:immunology*; D015854:Up-Regulation / Q000276:immunology
chemical_list: D015703:Antigens, CD; D060890:B7-H1 Antigen; C423236:CD274 protein, human; D034741:RNA, Small Interfering; D007371:Interferon-gamma