title: Natural killer cells recruited into lymph nodes inhibit alloreactive T-cell activation through perforin-mediated killing of donor allogeneic dendritic cells.
abstract: Natural killer (NK)-cell alloreactivity is exploited in bone marrow transplantation to improve clinical outcome. Likewise, in solid organ transplantation, it has been recently shown that recipient NK cells may limit alloreactive T-cell responses through their capacity to prevent the persistence of graft-derived allogeneic dendritic cells (DCs). In a model of CD4(+) T cell-mediated allogeneic skin graft rejection, we show that the absence of host NK-cell alloreactivity was characterized by enhanced expansion of alloreactive effector T lymphocytes, including Th2 cells, and massive eosinophilic infiltrates in the rejected tissues. In CD8(+) T cell-deficient C57BL/6 (H-2(b)) recipients injected with allogeneic BALB/c (H-2(d)) DCs, we demonstrated that NK cells expressing the H-2D(d)-specific Ly49D activating receptor were implicated in the regulation of alloreactive CD4(+) T-cell responses. Moreover, we showed that Ly49D(+) CD127(-) NK cells were recruited within DC draining lymph nodes and rapidly eliminated allogeneic H-2(d) DCs through the perforin pathway. In normal mice, we further demonstrated that NK cells by quickly eliminating allogeneic DCs strongly inhibited alloreactive CD8(+) T-cell responses. Thus, NK cells act as early regulators of alloreactive T-cell priming in allotransplantation through their capacity to kill allogeneic DCs in draining lymph nodes.
authors.affiliation: INSERM U563, Centre de Physiopathologie de Toulouse Purpan, Toulouse, France.
authors.forename: Sophie
authors.initials: S
authors.lastname: Laffont
authors.forename: Cyril
authors.initials: C
authors.lastname: Seillet
authors.forename: John
authors.initials: J
authors.lastname: Ortaldo
authors.forename: Jérôme D
authors.initials: JD
authors.lastname: Coudert
authors.forename: Jean-Charles
authors.initials: JC
authors.lastname: Guéry
mesh_terms: D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes; D002465:Cell Movement / Q000276:immunology; D003602:Cytotoxicity, Immunologic; D003713:Dendritic Cells / Q000276:immunology / Q000637:transplantation*; D006084:Graft Rejection; D007694:Killer Cells, Natural / Q000502:physiology*; D008198:Lymph Nodes / Q000276:immunology*; D008213:Lymphocyte Activation; D051379:Mice; D054353:Perforin; D016038:Skin Transplantation
chemical_list: D054353:Perforin