RESUMO
We developed a rapid method to remove the native mouse thymus from NSG mice, which allowed us to compare the behavior of human immune cells in the presence or absence of human T cells in human immune system mice. Removing the native mouse thymus is critical for studies of human thymopiesis in grafted thymic tissue in humanized mice.
Assuntos
Timectomia/métodos , Timo/imunologia , Timo/transplante , Transplante Heterólogo/métodos , Animais , Humanos , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCIDRESUMO
We evaluated the role of the thymus in development of multi-organ autoimmunity in human immune system (HIS) mice. T cells were essential for disease development and the same T cell clones with varying phenotypes infiltrated multiple tissues. De novo-generated hematopoietic stem cell (HSC)-derived T cells were the major disease drivers, though thymocytes pre-existing in grafted human thymi contributed if not first depleted. HIS mice with a native mouse thymus developed disease earlier than thymectomized mice with a thymocyte-depleted human thymus graft. Defective structure in the native mouse thymus was associated with impaired negative selection of thymocytes expressing a transgenic TCR recognizing a self-antigen. Disease developed without direct recognition of antigens on recipient mouse MHC. While human thymus grafts had normal structure and negative selection, failure to tolerize human T cells recognizing mouse antigens presented on HLA molecules may explain eventual disease development. These new insights have implications for human autoimmunity and suggest methods of avoiding autoimmunity in next-generation HIS mice.
Assuntos
Doenças Autoimunes/etiologia , Doenças Autoimunes/metabolismo , Autoimunidade , Suscetibilidade a Doenças/imunologia , Timo/imunologia , Timo/metabolismo , Animais , Antígenos , Doenças Autoimunes/patologia , Biomarcadores , Seleção Clonal Mediada por Antígeno/imunologia , Modelos Animais de Doenças , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Imuno-Histoquímica , Imunofenotipagem , Linfopoese/genética , Linfopoese/imunologia , Camundongos , Camundongos Knockout , Camundongos Transgênicos , Especificidade de Órgãos/imunologia , Receptores de Antígenos de Linfócitos T/genética , Receptores de Antígenos de Linfócitos T/metabolismo , Receptores de Antígenos de Linfócitos T alfa-beta/genética , Receptores de Antígenos de Linfócitos T alfa-beta/metabolismo , Linfócitos T/imunologia , Linfócitos T/metabolismoRESUMO
Gangliosides shed by tumors into their microenvironment (TME) are immunoinhibitory. Interferon-γ (IFN-γ) may boost antitumor immune responses. Thus we wondered whether IFN-γ would counteract tumor ganglioside-mediated immune suppression. To test this hypothesis, we exposed human monocyte-derived LPS-activated dendritic cells (DC) to IFN-γ and to a highly purified ganglioside, GD1a. DC ganglioside exposure decreased TLR-dependent p38 signaling, explaining the previously observed ganglioside-induced down-modulation of pro-inflammatory surface markers and cytokines. Strikingly, while increasing LPS-dependent DC responses, IFN-γ unexpectedly did not counteract the inhibitory effects of GD1a. Rather, induction of indoleamine 2,3-dioxygenase (IDO1), and expression of STAT1/IRF-1 and programmed cell death ligand (PD-L1), indicated that the immunoinhibitory, not an immune stimulatory, IFN-γ-signaling axis, was active. The combination, IFN-γ and DC ganglioside enrichment, markedly impaired DC stimulatory potential of CD8+ T-cells. We suggest that gangliosides and IFN-γ may act in concert as immunosuppressive mediators in the TME, possibly promoting tumor progression.