RESUMEN
Environmental signals shape host physiology and fitness. Microbiota-derived cues are required to program conventional dendritic cells (cDCs) during the steady state so that they can promptly respond and initiate adaptive immune responses when encountering pathogens. However, the molecular underpinnings of microbiota-guided instructive programs are not well understood. Here, we report that the indigenous microbiota controls constitutive production of type I interferons (IFN-I) by plasmacytoid DCs. Using genome-wide analysis of transcriptional and epigenetic regulomes of cDCs from germ-free and IFN-I receptor (IFNAR)-deficient mice, we found that tonic IFNAR signaling instructs a specific epigenomic and metabolic basal state that poises cDCs for future pathogen combat. However, such beneficial biological function comes with a trade-off. Instructed cDCs can prime T cell responses against harmless peripheral antigens when removing roadblocks of peripheral tolerance. Our data provide fresh insights into the evolutionary trade-offs that come with successful adaptation of vertebrates to their microbial environment.
Asunto(s)
Células Dendríticas/inmunología , Interferón Tipo I/inmunología , Microbiota/inmunología , Inmunidad Adaptativa/inmunología , Inmunidad Adaptativa/fisiología , Animales , Linfocitos T CD8-positivos/inmunología , Células Dendríticas/microbiología , Femenino , Masculino , Ratones , Ratones Endogámicos C57BL , Microbiota/fisiología , Receptor de Interferón alfa y beta/metabolismo , Transducción de Señal/inmunologíaRESUMEN
This article is part of the Dendritic Cell Guidelines article series, which provides a collection of state-of-the-art protocols for the preparation, phenotype analysis by flow cytometry, generation, fluorescence microscopy and functional characterization of mouse and human dendritic cells (DC) from lymphoid organs and various nonlymphoid tissues. DC are sentinels of the immune system present in almost every mammalian organ. Since they represent a rare cell population, DC need to be extracted from organs with protocols that are specifically developed for each tissue. This article provides detailed protocols for the preparation of single-cell suspensions from various mouse nonlymphoid tissues, including skin, intestine, lung, kidney, mammary glands, oral mucosa and transplantable tumors. Furthermore, our guidelines include comprehensive protocols for multiplex flow cytometry analysis of DC subsets and feature top tricks for their proper discrimination from other myeloid cells. With this collection, we provide guidelines for in-depth analysis of DC subsets that will advance our understanding of their respective roles in healthy and diseased tissues. While all protocols were written by experienced scientists who routinely use them in their work, this article was also peer-reviewed by leading experts and approved by all coauthors, making it an essential resource for basic and clinical DC immunologists.
Asunto(s)
Células Dendríticas , Piel , Animales , Humanos , Citometría de Flujo , Células Mieloides , Riñón , MamíferosRESUMEN
Dendritic cells (DCs) are the key APCs not only for the priming of naïve T cells, but also for the induction and maintenance of peripheral T-cell tolerance. We have recently shown that cognate interactions between Foxp3(+) Tregs and steady-state DCs are crucial to maintain the tolerogenic potential of DCs. Using DIETER mice, which allow the induction of antigen presentation selectively on DCs without altering their maturation status, we show here that breakdown of CD8(+) T-cell tolerance, which ensues after depletion of suppressive CD4(+) T cells, is driven by a positive feedback loop in which autoreactive CD8(+) T cells activate DCs via CD40. These data identify ligation of CD40 on DCs as a stimulus that promotes autoreactive T-cell priming when regulatory T-cell suppression fails and suggest that feedback from autoreactive T cells to DCs may contribute to the well-documented involvement of CD40 in many autoimmune diseases.
Asunto(s)
Linfocitos T CD4-Positivos/inmunología , Antígenos CD40/inmunología , Ligando de CD40/inmunología , Linfocitos T CD8-positivos/inmunología , Tolerancia Inmunológica/inmunología , Animales , Anticuerpos Monoclonales/farmacología , Presentación de Antígeno/inmunología , Trasplante de Médula Ósea , Linfocitos T CD4-Positivos/metabolismo , Antígenos CD40/genética , Antígenos CD40/metabolismo , Ligando de CD40/genética , Ligando de CD40/metabolismo , Linfocitos T CD8-positivos/metabolismo , Línea Celular Tumoral , Células Dendríticas/inmunología , Células Dendríticas/metabolismo , Retroalimentación Fisiológica/efectos de los fármacos , Citometría de Flujo , Tolerancia Inmunológica/genética , Coriomeningitis Linfocítica/inmunología , Coriomeningitis Linfocítica/virología , Virus de la Coriomeningitis Linfocítica/inmunología , Virus de la Coriomeningitis Linfocítica/fisiología , Ratones Endogámicos C57BL , Ratones Noqueados , Ratones Transgénicos , Linfocitos T Citotóxicos/inmunología , Linfocitos T Citotóxicos/metabolismo , Quimera por Trasplante/sangre , Quimera por Trasplante/inmunologíaRESUMEN
Resting dendritic cells (DCs) induce tolerance of peripheral T cells that have escaped thymic negative selection and thus contribute significantly to protection against autoimmunity. We recently showed that CD4(+)Foxp3(+) regulatory T cells (Tregs) are important for maintaining the steady-state phenotype of DCs and their tolerizing capacity in vivo. We now provide evidence that DC activation in the absence of Tregs is a direct consequence of missing DC-Treg interactions rather than being secondary to generalized autoimmunity in Treg-less mice. We show that DCs that lack MHC class II and thus cannot make cognate interactions with CD4(+) T cells are completely unable to induce peripheral CD8(+) T-cell tolerance. Consequently, mice in which interactions between DC and CD4(+) T cells are not possible develop spontaneous and fatal cytotoxic T lymphocyte-mediated autoimmunity.
Asunto(s)
Inmunidad Adaptativa/inmunología , Autoinmunidad/inmunología , Células Dendríticas/inmunología , Tolerancia Periférica/inmunología , Linfocitos T Citotóxicos/inmunología , Linfocitos T Reguladores/inmunología , Animales , Peso Corporal , Células Dendríticas/metabolismo , Citometría de Flujo , Genes MHC Clase II/genética , Genes MHC Clase II/inmunología , Técnicas Histológicas , Proteínas de Homeodominio , Activación de Linfocitos/inmunología , Ratones , Ratones Transgénicos , TamoxifenoRESUMEN
Dendritic cells (DCs) are important inducers and regulators of T-cell responses. They are able to activate and modulate the differentiation of CD4+ and CD8+ T cells. In the skin, there are at least five phenotypically distinct DC subpopulations that can be distinguished by differential expression of the cell surface markers CD207, CD103, and CD11b. Previous studies have suggested that dermal CD11b-CD207+ conventional type 1 DCs are indispensable for the priming of a skin homing cytotoxic T-lymphocyte response. However, conventional type 1 DCs are also the only skin DC subset capable of cross-presenting exogenous antigens on major histocompatibility complex class I. Thus, it remained unclear whether for antigens that do not require cross-presentation, such as viruses that infect DCs, other DC subtypes in the skin can contribute to cytotoxic T-lymphocyte priming. To address this question, we used a transgenic mouse model that allows inducible expression and presentation of a model antigen on selected subsets of dermal DCs. We show that for antigens presented via the conventional major histocompatibility complex class I presentation pathway, CD207- dermal DCs are fully competent to prime a skin homing cytotoxic T-lymphocyte response that is capable of protection against a local virus challenge and gives rise to skin resident memory CD8+ T cells.