RESUMEN
Despite the classical function of NK cells in the elimination of tumor and of virus-infected cells, evidence for a regulatory role for NK cells has been emerging in different models of autoimmunity, transplantation, and viral infections. However, this role has not been fully explored in the context of a growing tumor. In this article, we show that NK cells can limit spontaneous cross-priming of tumor Ag-specific CD8(+) T cells, leading to reduced memory responses. After challenge with MC57 cells transduced to express the model Ag SIY (MC57.SIY), NK cell-depleted mice exhibited a significantly higher frequency of SIY-specific CD8(+) T cells, with enhanced IFN-γ production and cytotoxic capability. Depletion of NK cells resulted in a CD8(+) T cell population skewed toward an effector memory T phenotype that was associated with enhanced recall responses and delayed tumor growth after a secondary tumor challenge with B16.SIY cells. Dendritic cells (DCs) from NK cell-depleted tumor-bearing mice exhibited a more mature phenotype. Interestingly, tumor-infiltrating and tumor-draining lymph node NK cells displayed an upregulated expression of the inhibitory molecule programmed death ligand 1 that, through interaction with programmed death-1 expressed on DCs, limited DC activation, explaining their reduced ability to induce tumor-specific CD8(+) T cell priming. Our results suggest that NK cells can, in certain contexts, have an inhibitory effect on antitumor immunity, a finding with implications for immunotherapy in the clinic.
Asunto(s)
Linfocitos T CD8-positivos/inmunología , Reactividad Cruzada/inmunología , Células Dendríticas/inmunología , Células Asesinas Naturales/inmunología , Activación de Linfocitos/inmunología , Neoplasias Experimentales/inmunología , Animales , Antígeno B7-H1/inmunología , Línea Celular Tumoral , Separación Celular , Citometría de Flujo , Humanos , Ratones , Ratones Endogámicos C57BL , Receptor de Muerte Celular Programada 1/inmunología , Reacción en Cadena en Tiempo Real de la Polimerasa , Transducción de Señal/inmunologíaRESUMEN
Cross-talk between mature dendritic cells (mDC) and NK cells through the cell surface receptors NKp30 and DNAM-1 leads to their reciprocal activation. However, the impact of regulatory dendritic cells (regDC) on NK cell function remains unknown. As regDC constrain the immune response in different physiological and pathological conditions, the aim of this work was to investigate the functional outcome of the interaction between regDC and NK cells and the associated underlying mechanisms. RegDC generated from monocyte-derived DC treated either with LPS and dexamethasone, vitamin D3, or vitamin D3 and dexamethasone instructed NK cells to secrete lower amounts of IFN-γ than NK cells exposed to mDC. Although regDC triggered upregulation of the activation markers CD69 and CD25 on NK cells, they did not induce upregulation of CD56 as mDC, and silenced IFN-γ secretion through mechanisms involving insufficient secretion of IL-18, but not IL-12 or IL-15 and/or induction of NK cell apoptosis. Blocking experiments demonstrated that regDC curb IFN-γ secretion by NK cells through a dominant suppressive mechanism involving IL-10, NK cell inhibitory receptors, and, unexpectedly, engagement of the activating receptor NKp46. Our findings unveil a previously unrecognized cross-talk through which regDC shape NK cell function toward an alternative activated phenotype unable to secrete IFN-γ, highlighting the plasticity of NK cells in response to tolerogenic stimuli. In addition, our findings contribute to identify a novel inhibitory role for NKp46 in the control of NK cell function, and have broad implications in the resolution of inflammatory responses and evasion of antitumor responses.
Asunto(s)
Receptores Coestimuladores e Inhibidores de Linfocitos T/inmunología , Células Dendríticas/inmunología , Interferón gamma/inmunología , Interleucina-10/inmunología , Células Asesinas Naturales/inmunología , Receptor 1 Gatillante de la Citotoxidad Natural/inmunología , Comunicación Celular/efectos de los fármacos , Comunicación Celular/inmunología , Células Cultivadas , Colecalciferol/inmunología , Colecalciferol/farmacología , Receptores Coestimuladores e Inhibidores de Linfocitos T/metabolismo , Células Dendríticas/efectos de los fármacos , Células Dendríticas/metabolismo , Dexametasona/inmunología , Dexametasona/farmacología , Citometría de Flujo , Glucocorticoides/inmunología , Glucocorticoides/farmacología , Antígenos de Histocompatibilidad Clase I/inmunología , Humanos , Interferón gamma/biosíntesis , Interleucina-10/metabolismo , Interleucina-12/inmunología , Interleucina-12/metabolismo , Interleucina-18/inmunología , Interleucina-18/metabolismo , Células Asesinas Naturales/efectos de los fármacos , Células Asesinas Naturales/metabolismo , Lipopolisacáridos/inmunología , Lipopolisacáridos/farmacología , Receptor 1 Gatillante de la Citotoxidad Natural/metabolismo , Receptor Cross-Talk/efectos de los fármacos , Receptor Cross-Talk/inmunología , Vitaminas/inmunología , Vitaminas/farmacologíaRESUMEN
IL-27, a member of the IL-12 family of cytokines, is produced by APCs, and displays pro- and anti-inflammatory effects. How IL-27 affects human NK cells still remains unknown. In this study, we observed that mature DCs secreted IL-27 and that blockade of IL-27R (CD130) reduced the amount of IFN-γ produced by NK cells during their coculture, showing the importance of IL-27 during DC-NK-cell crosstalk. Accordingly, human rIL-27 stimulated IFN-γ secretion by NK cells in a STAT1-dependent manner, induced upregulation of CD25 and CD69 on NK cells, and displayed a synergistic effect with IL-18. Preincubation experiments demonstrated that IL-27 primed NK cells for IL-18-induced IFN-γ secretion, which was associated with an IL-27-driven upregulation of T-bet expression. Also, IL-27 triggered NKp46-dependent NK-cell-mediated cytotoxicity against Raji, T-47D, and HCT116 cells, and IL-18 enhanced this cytotoxic response. Such NK-cell-mediated cytotoxicity involved upregulation of perforin, granule exocytosis, and TRAIL-mediated cytotoxicity but not Fas-FasL interaction. Moreover, IL-27 also potentiated Ab-dependent cell-mediated cytotoxicity against mAb-coated target cells. Taken together, IL-27 stimulates NK-cell effector functions, which might be relevant in different physiological and pathological situations.
Asunto(s)
Células Dendríticas/inmunología , Interleucina-18/farmacología , Interleucinas/farmacología , Células Asesinas Naturales/inmunología , Anticuerpos Monoclonales/farmacología , Antígenos CD/genética , Antígenos CD/inmunología , Antígenos de Diferenciación de Linfocitos T/genética , Antígenos de Diferenciación de Linfocitos T/inmunología , Proliferación Celular/efectos de los fármacos , Supervivencia Celular/inmunología , Técnicas de Cocultivo , Receptor gp130 de Citocinas/genética , Receptor gp130 de Citocinas/inmunología , Citotoxicidad Inmunológica , Células Dendríticas/citología , Células Dendríticas/efectos de los fármacos , Regulación de la Expresión Génica , Células HCT116 , Humanos , Interleucina-18/inmunología , Subunidad alfa del Receptor de Interleucina-2/genética , Subunidad alfa del Receptor de Interleucina-2/inmunología , Interleucinas/inmunología , Células Asesinas Naturales/citología , Células Asesinas Naturales/efectos de los fármacos , Lectinas Tipo C/genética , Lectinas Tipo C/inmunología , Cultivo Primario de Células , Proteínas Recombinantes/farmacología , Transducción de SeñalRESUMEN
Natural Killer (NK) cells play a key role in cancer immunosurveillance. However, NK cells from cancer patients display an altered phenotype and impaired effector functions. In addition, evidence of a regulatory role for NK cells is emerging in diverse models of viral infection, transplantation, and autoimmunity. Here, we analyzed clear cell renal cell carcinoma (ccRCC) datasets from The Cancer Genome Atlas (TCGA) and observed that a higher expression of NK cell signature genes is associated with reduced survival. Analysis of fresh tumor samples from ccRCC patients unraveled the presence of a high frequency of tumor-infiltrating PD-L1+ NK cells, suggesting that these NK cells might exhibit immunoregulatory functions. In vitro, PD-L1 expression was induced on NK cells from healthy donors (HD) upon direct tumor cell recognition through NKG2D and was further up-regulated by monocyte-derived IL-18. Moreover, in vitro generated PD-L1hi NK cells displayed an activated phenotype and enhanced effector functions compared to PD-L1- NK cells, but simultaneously, they directly inhibited CD8+ T cell proliferation in a PD-L1-dependent manner. Our results suggest that tumors might drive the development of PD-L1-expressing NK cells that acquire immunoregulatory functions in humans. Hence, rational manipulation of these regulatory cells emerges as a possibility that may lead to improved anti-tumor immunity in cancer patients.
Asunto(s)
Antígeno B7-H1/biosíntesis , Linfocitos T CD8-positivos/citología , Carcinoma de Células Renales/inmunología , Neoplasias Renales/inmunología , Células Asesinas Naturales/metabolismo , Carcinoma de Células Renales/genética , Carcinoma de Células Renales/metabolismo , Carcinoma de Células Renales/mortalidad , Línea Celular Tumoral , Proliferación Celular , Células Cultivadas , Conjuntos de Datos como Asunto , Supervivencia sin Enfermedad , Expresión Génica , Humanos , Interferón gamma/farmacología , Interleucina-18/farmacología , Células K562 , Estimación de Kaplan-Meier , Neoplasias Renales/genética , Neoplasias Renales/metabolismo , Neoplasias Renales/mortalidad , Monitorización Inmunológica , Monocitos/metabolismo , Proteínas Recombinantes/farmacología , Regulación hacia ArribaRESUMEN
The aim of this work is to determine the binding of ionic calcium (Ca(2+)) to lipid membranes in which the availability of the phosphate groups to the aqueous phase is modified by the degree of saturation of the lipids and the inclusion of cholesterol. The shifts in the phosphate bands observed in the Fourier transform infrared spectroscopy (FTIR) spectra are direct evidence of the interaction of Ca(2+) with phosphate groups. The binding analysis was done by determining the changes in the zeta potential of liposomes suspended in buffer at controlled temperature. The changes produced by the ion on the zeta potential of dioleoylphosphatidylcholine (DOPC); dipalmitoylphosphatidylcholine (DPPC); distearoylphosphatidylcholine (DSPC); dimyristoylphosphatidylethanolamine (DMPE) and their mixers with cholesterol were measured, showing a Langmuir isotherm behavior in all the lipid composition assayed. The results show that the interaction of Ca(2+) to lipid membranes depends on the exposure and the density of phosphate groups at the membrane interphase.