title: Peripheral deletional tolerance of alloreactive CD8 but not CD4 T cells is dependent on the PD-1/PD-L1 pathway.
abstract: Although interaction between programmed death-1 (PD-1) and the ligand PD-L1 has been shown to mediate CD8 cell exhaustion in the setting of chronic infection or the absence of CD4 help, a role for this pathway in attenuating early alloreactive CD8 cell responses has not been identified. We demonstrate that the PD-1/PD-L1 pathway is needed to rapidly tolerize alloreactive CD8 cells in a model that requires CD4 cells and culminates in CD8 cell deletion. This protocol involves allogeneic bone marrow transplantation (BMT) following conditioning with low-dose total body irradiation and anti-CD154 antibody. Tolerized donor-reactive T-cell receptor transgenic CD8 cells are shown to be in an abortive activation state prior to their deletion, showing early and prolonged expression of activation markers (compared with rejecting CD8 cells) while being functionally silenced by day 4 after transplantation. Although both tolerized and rejecting alloreactive CD8 cells up-regulate PD-1, CD8 cell tolerance is dependent on the PD-1/PD-L1 pathway. In contrast, CD4 cells are tolerized independently of this pathway following BMT with anti-CD154. These studies demonstrate a dichotomy between the requirements for CD4 and CD8 tolerance and identify a role for PD-1 in the rapid tolerization of an alloreactive T-cell population via a deletional mechanism.
authors.affiliation: Transplantation Biology Research Center, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02129, USA.
authors.forename: Fabienne
authors.initials: F
authors.lastname: Haspot
authors.forename: Thomas
authors.initials: T
authors.lastname: Fehr
authors.forename: Carrie
authors.initials: C
authors.lastname: Gibbons
authors.forename: Guiling
authors.initials: G
authors.lastname: Zhao
authors.forename: Timothy
authors.initials: T
authors.lastname: Hogan
authors.forename: Tasuku
authors.initials: T
authors.lastname: Honjo
authors.forename: Gordon J
authors.initials: GJ
authors.lastname: Freeman
authors.forename: Megan
authors.initials: M
authors.lastname: Sykes
mesh_terms: D000818:Animals; D000938:Antigen-Presenting Cells / Q000276:immunology; D000954:Antigens, Surface / Q000235:genetics / Q000276:immunology*; D051017:Apoptosis Regulatory Proteins / Q000172:deficiency / Q000235:genetics / Q000276:immunology*; D018122:B7-1 Antigen / Q000235:genetics / Q000276:immunology*; D060890:B7-H1 Antigen; D016026:Bone Marrow Transplantation / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D005260:Female; D007108:Immune Tolerance; D008213:Lymphocyte Activation; D008562:Membrane Glycoproteins / Q000172:deficiency / Q000235:genetics / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic; D018448:Models, Immunological; D010455:Peptides / Q000172:deficiency / Q000235:genetics / Q000276:immunology*; D061026:Programmed Cell Death 1 Receptor; D014184:Transplantation, Homologous
chemical_list: D000954:Antigens, Surface; D051017:Apoptosis Regulatory Proteins; D018122:B7-1 Antigen; D060890:B7-H1 Antigen; C498919:Cd274 protein, mouse; D008562:Membrane Glycoproteins; C491383:Pdcd1 protein, mouse; D010455:Peptides; D061026:Programmed Cell Death 1 Receptor