RESUMEN
ICOS is a T-cell coregulatory receptor that provides a costimulatory signal to T cells during antigen-mediated activation. Antitumor immunity can be improved by ICOS-targeting therapies, but their mechanism of action remains unclear. Here, we define the role of ICOS signaling in antitumor immunity using a blocking, nondepleting antibody against ICOS ligand (ICOS-L). ICOS signaling provided critical support for the effector function of CD4(+) Foxp3(-) T cells during anti-OX40-driven tumor immune responses. By itself, ICOS-L blockade reduced accumulation of intratumoral T regulatory cells (Treg), but it was insufficient to substantially inhibit tumor growth. Furthermore, it did not impede antitumor responses mediated by anti-4-1BB-driven CD8(+) T cells. We found that anti-OX40 efficacy, which is based on Treg depletion and to a large degree on CD4(+) effector T cell (Teff) responses, was impaired with ICOS-L blockade. In contrast, the provision of additional ICOS signaling through direct ICOS-L expression by tumor cells enhanced tumor rejection and survival when administered along with anti-OX40 therapy. Taken together, our results showed that ICOS signaling during antitumor responses acts on both Teff and Treg cells, which have opposing roles in promoting immune activation. Thus, effective therapies targeting the ICOS pathway should seek to promote ICOS signaling specifically in effector CD4(+) T cells by combining ICOS agonism and Treg depletion. Cancer Res; 76(13); 3684-9. ©2016 AACR.
Asunto(s)
Adenocarcinoma/inmunología , Linfocitos T CD8-positivos/inmunología , Neoplasias Colorrectales/inmunología , Receptores OX40/metabolismo , Linfocitos T Reguladores/inmunología , Adenocarcinoma/metabolismo , Adenocarcinoma/prevención & control , Animales , Neoplasias Colorrectales/metabolismo , Neoplasias Colorrectales/prevención & control , Citocinas/metabolismo , Femenino , Citometría de Flujo , Humanos , Ligando Coestimulador de Linfocitos T Inducibles/metabolismo , Activación de Linfocitos , Ratones , Ratones Endogámicos BALB C , Ratones Desnudos , Receptores de Antígenos de Linfocitos T , Transducción de Señal , Células Tumorales Cultivadas , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Stable Foxp3 expression is crucial for regulatory T (Treg) cell function. We observed that antigen-driven activation and inflammation in the CNS promoted Foxp3 instability selectively in the autoreactive Treg cells that expressed high amounts of Foxp3 before experimental autoimmune encephalitis induction. Treg cells with a demethylated Treg-cell-specific demethylated region in the Foxp3 locus downregulated Foxp3 transcription in the inflamed CNS during the induction phase of the response. Stable Foxp3 expression returned at the population level with the resolution of inflammation or was rescued by IL-2-anti-IL-2 complex treatment during the antigen priming phase. Thus, a subset of fully committed self-antigen-specific Treg cells lost Foxp3 expression during an inflammatory autoimmune response and might be involved in inadequate control of autoimmunity. These results have important implications for Treg cell therapies and give insights into the dynamics of the Treg cell network during autoreactive CD4(+) T cell effector responses in vivo.
Asunto(s)
Autoantígenos/inmunología , Encefalomielitis Autoinmune Experimental/inmunología , Factores de Transcripción Forkhead/fisiología , Regulación de la Expresión Génica/inmunología , Linfocitos T Reguladores/inmunología , Animales , Linfocitos T CD4-Positivos/inmunología , Linaje de la Célula , Sistema Nervioso Central/inmunología , Metilación de ADN , Regulación hacia Abajo/inmunología , Factores de Transcripción Forkhead/biosíntesis , Factores de Transcripción Forkhead/genética , Genes Reporteros , Ganglios Linfáticos/inmunología , Activación de Linfocitos , Ratones , Ratones Endogámicos C57BL , Glicoproteína Mielina-Oligodendrócito/inmunología , Fragmentos de Péptidos/inmunología , Receptores de Interleucina-2/fisiología , Proteínas Recombinantes de Fusión/inmunología , Secuencias Reguladoras de Ácidos Nucleicos , Organismos Libres de Patógenos EspecíficosRESUMEN
During the initial hours after activation, CD4(+) T cells experience profound changes in gene expression. Co-stimulation via the CD28 receptor is required for efficient activation of naive T cells. However, the transcriptional consequences of CD28 co-stimulation are not completely understood. We performed expression microarray analysis to elucidate the effects of CD28 signals on the transcriptome of activated T cells. We show that the transcription factor DEC1 is highly induced in a CD28-dependent manner upon T cell activation, is involved in essential CD4(+) effector T cell functions, and participates in the transcriptional regulation of several T cell activation pathways, including a large group of CD28-regulated genes. Antigen-specific, DEC1-deficient CD4(+) T cells have cell-intrinsic defects in survival and proliferation. Furthermore, we found that DEC1 is required for the development of experimental autoimmune encephalomyelitis because of its critical role in the production of the proinflammatory cytokines GM-CSF, IFN-γ, and IL-2. Thus, we identify DEC1 as a critical transcriptional mediator in the activation of naive CD4(+) T cells that is required for the development of a T cell-mediated autoimmune disease.
Asunto(s)
Autoinmunidad , Antígenos CD28/metabolismo , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD4-Positivos/metabolismo , Proteínas Supresoras de Tumor/metabolismo , Animales , Antígenos CD28/genética , Antígenos CD28/inmunología , Línea Celular , Proliferación Celular , Citocinas/biosíntesis , Encefalomielitis Autoinmune Experimental/genética , Encefalomielitis Autoinmune Experimental/inmunología , Perfilación de la Expresión Génica , Regulación de la Expresión Génica , Humanos , Mediadores de Inflamación/metabolismo , Interleucina-2/metabolismo , Activación de Linfocitos/genética , Ratones , Ratones Noqueados , Receptores de Antígenos de Linfocitos T/genética , Receptores de Antígenos de Linfocitos T/metabolismo , Transcriptoma , Proteínas Supresoras de Tumor/deficiencia , Proteínas Supresoras de Tumor/genéticaRESUMEN
Regulatory T cells (T(reg) cells) are essential for self-tolerance and immune homeostasis. Lack of effector T cell (T(eff) cell) function and gain of suppressive activity by T(reg) cells are dependent on the transcriptional program induced by Foxp3. Here we report that repression of SATB1, a genome organizer that regulates chromatin structure and gene expression, was crucial for the phenotype and function of T(reg) cells. Foxp3, acting as a transcriptional repressor, directly suppressed the SATB1 locus and indirectly suppressed it through the induction of microRNAs that bound the SATB1 3' untranslated region. Release of SATB1 from the control of Foxp3 in T(reg) cells caused loss of suppressive function, establishment of transcriptional T(eff) cell programs and induction of T(eff) cell cytokines. Our data support the proposal that inhibition of SATB1-mediated modulation of global chromatin remodeling is pivotal for maintaining T(reg) cell functionality.
Asunto(s)
Ensamble y Desensamble de Cromatina/inmunología , Factores de Transcripción Forkhead/inmunología , Regulación de la Expresión Génica , Proteínas de Unión a la Región de Fijación a la Matriz/inmunología , Autotolerancia , Linfocitos T Reguladores/inmunología , Regiones no Traducidas 3'/genética , Regiones no Traducidas 3'/inmunología , Animales , Diferenciación Celular/efectos de los fármacos , Ensamble y Desensamble de Cromatina/efectos de los fármacos , Citometría de Flujo , Factores de Transcripción Forkhead/genética , Factores de Transcripción Forkhead/metabolismo , Perfilación de la Expresión Génica , Genoma Humano , Estudio de Asociación del Genoma Completo , Humanos , Lentivirus , Activación de Linfocitos/efectos de los fármacos , Proteínas de Unión a la Región de Fijación a la Matriz/genética , Proteínas de Unión a la Región de Fijación a la Matriz/metabolismo , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , MicroARNs/inmunología , MicroARNs/metabolismo , MicroARNs/farmacología , Interferencia de ARN , ARN Interferente Pequeño/inmunología , ARN Interferente Pequeño/metabolismo , ARN Interferente Pequeño/farmacología , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Autotolerancia/efectos de los fármacos , Autotolerancia/genética , Autotolerancia/inmunología , Linfocitos T Reguladores/citología , Linfocitos T Reguladores/metabolismo , Transducción GenéticaRESUMEN
Breakdown in self-tolerance is caused, in part, by loss of regulatory T (Treg) cells. Recently, a controversy has surfaced about whether Treg cells are overwhelmingly stable, or if they can be reprogrammed in inflammatory and autoimmune environments. Those in the instability camp have shown that a fraction of Treg cells lose forkhead box P3 protein and acquire effector arm activities. Instability is coupled with interleukin-2 insufficiency and the inflammatory milieu that promotes reprogramming. Here, we highlight the basic tenets of each viewpoint and discuss technical, biological and environmental differences in the models that might help yield a unifying hypothesis. Also considered is how Treg cell instability could link to development of autoimmune disease and the implications for trials of Treg cell-based therapy.
Asunto(s)
Linfocitos T Reguladores/inmunología , Animales , Enfermedades Autoinmunes/inmunología , Enfermedades Autoinmunes/terapia , Diferenciación Celular , Humanos , Inflamación/inmunología , Linfocitos T Reguladores/citologíaRESUMEN
Th17 cells promote a variety of autoimmune diseases, including psoriasis, multiple sclerosis, rheumatoid arthritis, and inflammatory bowel disease. TGF-ß is required for conversion of naive T cells to Th17 cells, but the mechanisms regulating this process are unknown. Integrin αvß8 on DCs can activate TGF-ß, and this process contributes to the development of induced Tregs. Here, we have now shown that integrin αvß8 expression on DCs plays a critical role in the differentiation of Th17 cells. Th17 cells were nearly absent in the colons of mice lacking αvß8 expression on DCs. In addition, these mice and the DCs harvested from them had an impaired ability to convert naive T cells into Th17 cells in vivo and in vitro, respectively. Importantly, mice lacking αvß8 on DCs showed near-complete protection from experimental autoimmune encephalomyelitis. Our results therefore suggest that the integrin αvß8 pathway is biologically important and that αvß8 expression on DCs could be a therapeutic target for the treatment of Th17-driven autoimmune disease.
Asunto(s)
Células Dendríticas/inmunología , Encefalomielitis Autoinmune Experimental/inmunología , Integrinas/metabolismo , Células Th17/inmunología , Animales , Secuencia de Bases , Diferenciación Celular/inmunología , Colon/inmunología , Colon/patología , Citocinas/biosíntesis , Citocinas/genética , Cartilla de ADN/genética , Células Dendríticas/patología , Encefalomielitis Autoinmune Experimental/patología , Expresión Génica , Técnicas In Vitro , Integrinas/deficiencia , Integrinas/genética , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Ratones SCID , Ratones Transgénicos , ARN Mensajero/genética , ARN Mensajero/metabolismo , Células Th17/patologíaRESUMEN
Regulatory T cells (T(reg) cells) are central to the maintenance of immune homeostasis. However, little is known about the stability of T(reg) cells in vivo. In this study, we demonstrate that a substantial percentage of cells had transient or unstable expression of the transcription factor Foxp3. These 'exFoxp3' T cells had an activated-memory T cell phenotype and produced inflammatory cytokines. Moreover, exFoxp3 cell numbers were higher in inflamed tissues in autoimmune conditions. Adoptive transfer of autoreactive exFoxp3 cells led to the rapid onset of diabetes. Finally, analysis of the T cell receptor repertoire suggested that exFoxp3 cells developed from both natural and adaptive T(reg) cells. Thus, the generation of potentially autoreactive effector T cells as a consequence of Foxp3 instability has important implications for understanding autoimmune disease pathogenesis.
Asunto(s)
Factores de Transcripción Forkhead/fisiología , Memoria Inmunológica , Linfocitos T Reguladores/fisiología , Traslado Adoptivo , Secuencia de Aminoácidos , Animales , Enfermedades Autoinmunes/etiología , Regiones Determinantes de Complementariedad/química , Islas de CpG , Metilación de ADN , Células Madre Hematopoyéticas/fisiología , Inmunofenotipificación , Interferón gamma/biosíntesis , Interleucina-17/biosíntesis , Interleucina-2/farmacología , Proteínas Luminiscentes/metabolismo , Ratones , Ratones Endogámicos NOD , Datos de Secuencia Molecular , Receptores de Antígenos de Linfocitos T/fisiologíaRESUMEN
Plasmacytoid dendritic cells (pDCs) have both stimulatory and regulatory effects on T cells. pDCs are a major CNS-infiltrating dendritic cell population during experimental autoimmune encephalomyelitis but, unlike myeloid dendritic cells, have a minor role in T cell activation and epitope spreading. We show that depletion of pDCs during either the acute or relapse phases of experimental autoimmune encephalomyelitis resulted in exacerbation of disease severity. pDC depletion significantly enhanced CNS but not peripheral CD4(+) T cell activation, as well as IL-17 and IFN-gamma production. Moreover, CNS pDCs suppressed CNS myeloid dendritic cell-driven production of IL-17, IFN-gamma, and IL-10 in an IDO-independent manner. The data demonstrate that pDCs play a critical regulatory role in negatively regulating pathogenic CNS CD4(+) T cell responses, highlighting a new role for pDCs in inflammatory autoimmune disease.