RESUMEN
Oral tolerance prevents oral sensitization to dietary antigens (Ags), including proteins and haptens, and development of delayed-type hypersensitivity (DTH) responses. We showed here that plasmacytoid dendritic cells (pDCs) prevented oral T cell priming and were responsible for systemic tolerance to CD4(+) and CD8(+) T cell-mediated DTH responses induced by Ag feeding. Systemic depletion of pDCs prevented induction of tolerance by antigen feeding. Transfer of oral Ag-loaded liver pDCs to naive recipient mice induced Ag-specific suppression of CD4(+) and CD8(+) T cell responses to protein and hapten, respectively. Liver is a site of oral Ag presentation, and pDCs appeared to induce anergy or deletion of Ag-specific T cells in the liver relatively rapidly via a CD4(+) T cell-independent mechanism. These data demonstrate that oral tolerance relies on Ag presentation by pDC to T cells and suggest that pDC could represent a key therapeutic target for intestinal and systemic inflammatory diseases.
Asunto(s)
Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD8-positivos/inmunología , Células Dendríticas/inmunología , Hipersensibilidad Tardía/inmunología , Tolerancia Inmunológica , Mucosa Bucal/inmunología , Animales , Linfocitos T CD4-Positivos/metabolismo , Linfocitos T CD8-positivos/metabolismo , Células Dendríticas/metabolismo , Dinitrofluorobenceno/inmunología , Femenino , Hipersensibilidad Tardía/metabolismo , Hígado/inmunología , Ganglios Linfáticos/inmunología , Ratones , Ratones Endogámicos C57BL , Bazo/inmunologíaRESUMEN
Human monocyte-derived dendritic cell (MoDC) have been used in the clinic with moderately encouraging results. Mouse XCR1(+) DC excel at cross-presentation, can be targeted in vivo to induce protective immunity, and share characteristics with XCR1(+) human DC. Assessment of the immunoactivation potential of XCR1(+) human DC is hindered by their paucity in vivo and by their lack of a well-defined in vitro counterpart. We report in this study a protocol generating both XCR1(+) and XCR1(-) human DC in CD34(+) progenitor cultures (CD34-DC). Gene expression profiling, phenotypic characterization, and functional studies demonstrated that XCR1(-) CD34-DC are similar to canonical MoDC, whereas XCR1(+) CD34-DC resemble XCR1(+) blood DC (bDC). XCR1(+) DC were strongly activated by polyinosinic-polycytidylic acid but not LPS, and conversely for MoDC. XCR1(+) DC and MoDC expressed strikingly different patterns of molecules involved in inflammation and in cross-talk with NK or T cells. XCR1(+) CD34-DC but not MoDC efficiently cross-presented a cell-associated Ag upon stimulation by polyinosinic-polycytidylic acid or R848, likewise to what was reported for XCR1(+) bDC. Hence, it is feasible to generate high numbers of bona fide XCR1(+) human DC in vitro as a model to decipher the functions of XCR1(+) bDC and as a potential source of XCR1(+) DC for clinical use.
Asunto(s)
Antígenos CD34/inmunología , Células Sanguíneas/inmunología , Células Dendríticas/inmunología , Monocitos/inmunología , Receptores Acoplados a Proteínas G/inmunología , Adyuvantes Inmunológicos/farmacología , Presentación de Antígeno/inmunología , Técnicas de Cultivo de Célula , Diferenciación Celular/inmunología , Línea Celular , Reactividad Cruzada/inmunología , Perfilación de la Expresión Génica , Proteínas Fluorescentes Verdes , Humanos , Imidazoles/inmunología , Células Asesinas Naturales/inmunología , Lipopolisacáridos/inmunología , Fenotipo , Poli I-C/inmunología , Linfocitos T/inmunología , Receptor Toll-Like 3 , Receptor Toll-Like 4RESUMEN
Plasmacytoid dendritic cells (pDCs) are specialized producers of type I interferons (IFNs) that respond to most viruses. Because of their antiviral activity and regulatory functions in innate and adaptive immunity, type I IFNs are important not only for antiviral resistance but also in other types of infections and in immune pathology. Here we discuss recent data that begin to reveal the unique molecular mechanisms underlying the remarkably rapid and efficient type I IFN production by pDCs.
Asunto(s)
Células Dendríticas/inmunología , Inmunidad Innata , Interferón Tipo I/biosíntesis , Activación de Linfocitos/inmunología , Células Plasmáticas/inmunología , Virus/inmunología , Animales , Células Dendríticas/ultraestructura , Humanos , Células Plasmáticas/ultraestructuraRESUMEN
Differential expression of Toll-like receptor (TLR) by conventional dendritic cells (cDCs) and plasmacytoid DC (pDCs) has been suggested to influence the type of immune response induced by microbial pathogens. In this study we show that, in vivo, cDCs and pDCs are equally activated by TLR4, -7, and -9 ligands. Type I interferon (IFN) was important for pDC activation in vivo in response to all three TLR ligands, whereas cDCs required type I IFN signaling only for TLR9- and partially for TLR7-mediated activation. Although TLR ligands induced in situ migration of spleen cDC into the T cell area, spleen pDCs formed clusters in the marginal zone and in the outer T cell area 6 h after injection of TLR9 and TLR7 ligands, respectively. In vivo treatment with TLR9 ligands decreased pDC ability to migrate ex vivo in response to IFN-induced CXCR3 ligands and increased their response to CCR7 ligands. Unlike cDCs, the migration pattern of pDCs required type I IFN for induction of CXCR3 ligands and responsiveness to CCR7 ligands. These data demonstrate that mouse pDCs differ from cDCs in the in vivo response to TLR ligands, in terms of pattern and type I IFN requirement for activation and migration.
Asunto(s)
Movimiento Celular/inmunología , Células Dendríticas/metabolismo , Regulación de la Expresión Génica/inmunología , Interferón Tipo I/metabolismo , Glicoproteínas de Membrana/metabolismo , Receptores de Superficie Celular/metabolismo , Animales , Quimiotaxis/inmunología , Femenino , Citometría de Flujo , Imidazoles , Inmunohistoquímica , Ligandos , Ratones , Ratones Noqueados , Oligodesoxirribonucleótidos , Organismos Libres de Patógenos Específicos , Bazo/inmunología , Receptor Toll-Like 4 , Receptor Toll-Like 7 , Receptores Toll-LikeRESUMEN
An effective type I interferon (IFN-alpha/beta) response is critical for the control of many viral infections. Here we show that in vesicular stomatitis virus (VSV)-infected mouse embryonic fibroblasts (MEFs) the production of IFN-alpha is dependent on type I IFN receptor (IFNAR) triggering, whereas in infected mice early IFN-alpha production is IFNAR independent. In VSV-infected mice type I IFN is produced by few cells located in the marginal zone of the spleen. Unlike other dendritic cell (DC) subsets, FACS((R))-sorted CD11c(int)CD11b(-)GR-1(+) DCs show high IFN-alpha expression, irrespective of whether they were isolated from VSV-infected IFNAR-competent or -deficient mice. Thus, VSV preferentially activates a specialized DC subset presumably located in the marginal zone to produce high-level IFN-alpha largely independent of IFNAR feedback signaling.
Asunto(s)
Células Dendríticas/metabolismo , Células Dendríticas/virología , Interferón-alfa/biosíntesis , Receptores de Interferón/deficiencia , Receptores de Interferón/metabolismo , Virus de la Estomatitis Vesicular Indiana/fisiología , Animales , Células Cultivadas , Proteínas de Unión al ADN/metabolismo , Células Dendríticas/efectos de los fármacos , Retroalimentación Fisiológica , Fibroblastos/metabolismo , Fibroblastos/virología , Citometría de Flujo , Eliminación de Gen , Regulación de la Expresión Génica/efectos de los fármacos , Hibridación in Situ , Factor 7 Regulador del Interferón , Interferón-alfa/genética , Interferón-alfa/metabolismo , Interferón beta/metabolismo , Proteínas de la Membrana , Ratones , Ratones Endogámicos C57BL , Ratones Mutantes , Poli I-C/farmacología , ARN Mensajero/genética , ARN Mensajero/metabolismo , Receptor de Interferón alfa y beta , Receptores de Interferón/genética , Transducción de Señal/efectos de los fármacos , Bazo/metabolismo , Bazo/patología , Factores de Tiempo , Rayos UltravioletaRESUMEN
Distinct dendritic cell (DC) subsets have been suggested to be preprogrammed to direct either T helper cell (Th) type 1 or Th2 development, although more recently different pathogen products or stimuli have been shown to render these DCs more flexible. It is still unclear how distinct mouse DC subsets cultured from bone marrow precursors, blood, or their lymphoid tissue counterparts direct Th differentiation. We show that mouse myeloid and plasmacytoid precursor DCs (pDCs) cultured from bone marrow precursors and ex vivo splenic DC subsets can induce the development of both Th1 and Th2 effector cells depending on the dose of antigen. In general, high antigen doses induced Th1 cell development whereas low antigen doses induced Th2 cell development. Both cultured and ex vivo splenic plasmacytoid-derived DCs enhanced CD4(+) T cell proliferation and induced strong Th1 cell development when activated with the Toll-like receptor (TLR)9 ligand CpG, and not with the TLR4 ligand lipopolysaccharide (LPS). The responsiveness of plasmacytoid pDCs to CpG correlated with high TLR9 expression similarly to human plasmacytoid pDCs. Conversely, myeloid DCs generated with granulocyte/macrophage colony-stimulating factor enhanced Th1 cell development when stimulated with LPS as a result of their high level of TLR4 expression. Polarized Th1 responses resulting from high antigen dose were not additionally enhanced by stimulation of DCs by TLR ligands. Thus, the net effect of antigen dose, the state of maturation of the DCs together with the stimulation of DCs by pathogen-derived products, will determine whether a Th1 or Th2 response develops.
Asunto(s)
Antígenos/inmunología , Diferenciación Celular , Células Dendríticas/inmunología , Proteínas de Drosophila , Glicoproteínas de Membrana/metabolismo , Células Plasmáticas/inmunología , Receptores de Superficie Celular/metabolismo , Células TH1/inmunología , Células Th2/inmunología , Animales , División Celular , Islas de CpG/inmunología , Células Dendríticas/citología , Relación Dosis-Respuesta Inmunológica , Citometría de Flujo , Regulación de la Expresión Génica , Lipopolisacáridos/inmunología , Glicoproteínas de Membrana/genética , Ratones , Ratones Transgénicos , Células Mieloides/citología , Células Mieloides/inmunología , Células Plasmáticas/citología , ARN Mensajero/genética , ARN Mensajero/metabolismo , Receptores de Superficie Celular/genética , Células Madre/citología , Células Madre/inmunología , Células TH1/citología , Células TH1/metabolismo , Células Th2/citología , Células Th2/metabolismo , Receptor Toll-Like 4 , Receptores Toll-LikeRESUMEN
Interferon (IFN)-alpha/beta and interleukin (IL)-12 are cytokines critical in defense against viruses, but their cellular sources and mechanisms of regulation for in vivo expression remain poorly characterized. The studies presented here identified a novel subset of dendritic cells (DCs) as major producers of the cytokines during murine cytomegalovirus (MCMV) but not lymphocytic choriomeningitis virus (LCMV) infections. These DCs differed from those activated by Toxoplasma antigen but were related to plasmacytoid cells, as assessed by their CD8alpha(+)Ly6G/C(+)CD11b(-) phenotype. Another DC subset (CD8alpha(2)Ly6G/C(-)CD11b(+)) also contributed to IL-12 production in MCMV-infected immunocompetent mice, modestly. However, it dramatically increased IL-12 expression in the absence of IFN-alpha/beta functions. Conversely, IFN-alpha/beta production was greatly reduced under these conditions. Thus, a cross-regulation of DC subset cytokine responses was defined, whereby secretion of type I IFNs by CD8alpha(+) DCs resulted in responses limiting IL-12 expression by CD11b(+) DCs but enhancing overall IFN-alpha/beta production. Taken together, these data indicate that CD8alpha(+)Ly6G/C(+)CD11b(-) DCs play important roles in limiting viral replication and regulating immune responses, through cytokine production, in some but not all viral infections. They also illustrate the plasticity of cellular sources for innate cytokines in vivo and provide new insights into the roles of IFNs in shaping immune responses to viruses.
Asunto(s)
Células Dendríticas/inmunología , Células Dendríticas/metabolismo , Regulación de la Expresión Génica , Interferón-alfa/inmunología , Interferón beta/inmunología , Interleucina-12/inmunología , Virus de la Coriomeningitis Linfocítica/inmunología , Muromegalovirus/inmunología , Animales , Antígenos Virales/inmunología , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/metabolismo , Células Dendríticas/citología , Citometría de Flujo , Inmunohistoquímica , Interferón-alfa/biosíntesis , Interferón-alfa/genética , Interferón beta/biosíntesis , Interferón beta/genética , Interleucina-12/biosíntesis , Interleucina-12/genética , Células Asesinas Naturales/inmunología , Ratones , Ratones Endogámicos C57BL , Microscopía Fluorescente , Receptores de Interferón/metabolismo , Factor de Transcripción STAT1 , Transducción de Señal , Bazo/citología , Bazo/inmunología , Linfocitos T/inmunología , Transactivadores/genética , Transactivadores/metabolismoRESUMEN
The discovery of a targeted therapeutic compound along with its companion predictive biomarker is a major goal of clinical development for a personalized anticancer therapy to date. Here we present evidence of the predictive value of TLR3 expression by tumor cells for the efficacy of Poly (A:U) dsRNA in 194 breast cancer patients enrolled in a randomized clinical trial. Adjuvant treatment with double-stranded RNA (dsRNA) was associated with a significant decrease in the risk of metastatic relapse in TLR3 positive but not in TLR3-negative breast cancers. Moreover, we show the functional relevance of TLR3 expression by human tumor cells for the antitumor effects mediated by dsRNA in several preclinical mouse models carried out in immunocompromised animals. These 2 independent lines of evidence relied upon the generation of a novel tool, an anti-TLR3 antibody (40F9.6) validated for routine detection of TLR3 expression on paraffin-embedded tissues. Altogether, these data suggest that dsRNA mediates its therapeutic effect through TLR3 expressed on tumor cells, and could therefore represent an effective targeted treatment in patients with TLR3-positive cancers.
Asunto(s)
Anticuerpos Monoclonales , Antineoplásicos/uso terapéutico , Biomarcadores de Tumor/análisis , Neoplasias de la Mama/tratamiento farmacológico , ARN Bicatenario/uso terapéutico , Receptor Toll-Like 3/biosíntesis , Animales , Especificidad de Anticuerpos , Neoplasias de la Mama/metabolismo , Femenino , Humanos , Inmunohistoquímica , Ratones , Ratones Endogámicos BALB C , Estudios Multicéntricos como Asunto , Ensayos Clínicos Controlados Aleatorios como Asunto , Estudios Retrospectivos , Receptor Toll-Like 3/análisisRESUMEN
Plasmacytoid dendritic cells (pDCs) are specialized DCs that produce high levels of type I IFN upon viral infection. Despite their key immunoregulatory role, little is known about pDC ontogeny or how developmental events regulate their function. We show that mice expressing low levels of the transcription factor Ikaros (Ik(L/L)) lack peripheral pDCs, but not other DC subsets. Loss of pDCs is associated with an inability to produce type I IFN after challenge with Toll-like receptor-7 and -9 ligands, or murine cytomegalovirus (MCMV) infection. In contrast, conventional DCs are present in normal numbers and exhibit normal responses in vivo after challenge with MCMV or inactivated toxoplasma antigen. Interestingly, Ik(L/L) bone marrow (BM) cells contain a pDC population that appears blocked at the Ly-49Q- stage of differentiation and fails to terminally differentiate in response to Flt-3L, a cytokine required for pDC differentiation. This differentiation block is strictly dependent on a cell-intrinsic requirement for Ikaros in pDC-committed precursors. Global gene expression profiling of Ik(L/L) BM pDCs reveals an up-regulation of genes not normally expressed, or expressed at low levels, in WT pDCs. These studies suggest that Ikaros controls pDC differentiation by silencing a large array of genes.
Asunto(s)
Diferenciación Celular/inmunología , Células Dendríticas/inmunología , Factor de Transcripción Ikaros/inmunología , Células Plasmáticas/inmunología , Animales , Antígenos de Protozoos/inmunología , Células de la Médula Ósea/inmunología , Células de la Médula Ósea/metabolismo , Diferenciación Celular/genética , Regulación de la Expresión Génica/genética , Regulación de la Expresión Génica/inmunología , Infecciones por Herpesviridae/genética , Infecciones por Herpesviridae/inmunología , Factor de Transcripción Ikaros/biosíntesis , Factor de Transcripción Ikaros/genética , Interferón Tipo I/biosíntesis , Interferón Tipo I/inmunología , Glicoproteínas de Membrana/biosíntesis , Glicoproteínas de Membrana/inmunología , Ratones , Ratones Mutantes , Muromegalovirus/genética , Muromegalovirus/inmunología , Receptor Toll-Like 7/biosíntesis , Receptor Toll-Like 7/inmunología , Receptor Toll-Like 9/biosíntesis , Receptor Toll-Like 9/inmunología , Toxoplasma/inmunología , Tirosina Quinasa 3 Similar a fms/biosíntesis , Tirosina Quinasa 3 Similar a fms/inmunologíaRESUMEN
We have previously reported that mouse plasmacytoid dendritic cells (DC) produce high levels of IL-12p70, whereas bone marrow-derived myeloid DC and splenic DC produce substantially lower levels of this cytokine when activated with the TLR-9 ligand CpG. We now show that in response to CpG stimulation, high levels of IL-10 are secreted by macrophages, intermediate levels by myeloid DC, but no detectable IL-10 is secreted by plasmacytoid DC. MyD88-dependent TLR signals (TLR4, 7, 9 ligation), Toll/IL-1 receptor domain-containing adaptor-dependent TLR signals (TLR3, 4 ligation) as well as non-TLR signals (CD40 ligation) induced macrophages and myeloid DC to produce IL-10 in addition to proinflammatory cytokines. IL-12p70 expression in response to CpG was suppressed by endogenous IL-10 in macrophages, in myeloid DC, and to an even greater extent in splenic CD8alpha(-) and CD8alpha(+) DC. Although plasmacytoid DC did not produce IL-10 upon stimulation, addition of this cytokine exogenously suppressed their production of IL-12, TNF, and IFN-alpha, showing trans but not autocrine regulation of these cytokines by IL-10 in plasmacytoid DC.
Asunto(s)
Proteínas Adaptadoras del Transporte Vesicular/metabolismo , Células Dendríticas/metabolismo , Interleucina-10/metabolismo , Macrófagos/metabolismo , Células Mieloides/inmunología , Factor 88 de Diferenciación Mieloide/metabolismo , Proteínas Adaptadoras del Transporte Vesicular/inmunología , Animales , Células de la Médula Ósea/citología , Células de la Médula Ósea/inmunología , Antígenos CD8/inmunología , Antígenos CD8/metabolismo , Islas de CpG/inmunología , Células Dendríticas/citología , Células Dendríticas/inmunología , Interleucina-10/inmunología , Interleucina-12/biosíntesis , Interleucina-12/inmunología , Macrófagos/inmunología , Ratones , Factor 88 de Diferenciación Mieloide/inmunología , Bazo/citología , Bazo/inmunología , Receptores Toll-Like/inmunología , Receptores Toll-Like/metabolismoRESUMEN
Murine plasmacytoid dendritic cells (pDCs) have been credited with a unique ability to express indoleamine 2,3-dioxygenase (IDO) function and mediate immunosuppression in specific settings; yet, the conditions of spontaneous versus induced activity have remained unclear. We have used maneuvers known to up-regulate IDO in different cell types and have examined the relative efficacy and mechanisms of the induced activity in splenic pDCs, namely, after specific receptor engagement by CTLA-4-Ig, CD200-Ig or CD28-Ig, the latter in combination with silenced expression of the suppressor of cytokine signaling 3 (SOCS3) gene. We found that pDCs (CD11c+ mPDCA-1+ 120G8+) do not express IDO and are not tolerogenic under basal conditions. B7-1 engagement by CTLA-4-Ig, CD200R1 engagement by CD200-Ig and B7-1/B7-2 engagement by CD28-Ig in SOCS3-deficient pDCs were each capable of initiating IDO-dependent tolerance via different mechanisms. IFN-gamma was the major cytokine responsible for CTLA-4-Ig effects, and type I IFNs for those of CD200-Ig. Immunosuppression by CD28-Ig in the absence of SOCS3 required IFN-gamma induction and IFN-like actions of IL-6. Therefore, although pDCs do not mediate IDO-dependent tolerance constitutively, multiple ligands and cytokines will contribute to the expression of a tolerogenic phenotype by pDCs in the mouse.
Asunto(s)
Células Dendríticas/enzimología , Tolerancia Inmunológica , Indolamina-Pirrol 2,3,-Dioxigenasa/biosíntesis , Células Plasmáticas/enzimología , Animales , Antígenos CD/genética , Antígenos CD/inmunología , Citocinas/inmunología , Células Dendríticas/citología , Células Dendríticas/inmunología , Indolamina-Pirrol 2,3,-Dioxigenasa/inmunología , Ligandos , Ratones , Ratones Noqueados , Células Plasmáticas/citología , Células Plasmáticas/inmunología , Triptófano/inmunología , Triptófano/metabolismoRESUMEN
Dendritic cells (DCs) regulate various aspects of innate immunity, including natural killer (NK) cell function. Here we define the mechanisms involved in DC-NK cell interactions during viral infection. NK cells were efficiently activated by murine cytomegalovirus (MCMV)-infected CD11b(+) DCs. NK cell cytotoxicity required interferon-alpha and interactions between the NKG2D activating receptor and NKG2D ligand, whereas the production of interferon-gamma by NK cells relied mainly on DC-derived interleukin 18. Although Toll-like receptor 9 contributes to antiviral immunity, we found that signaling pathways independent of Toll-like receptor 9 were important in generating immune responses to MCMV, including the production of interferon-alpha and the induction of NK cell cytotoxicity. Notably, adoptive transfer of MCMV-activated CD11b(+) DCs resulted in improved control of MCMV infection, indicating that these cells participate in controlling viral replication in vivo.
Asunto(s)
Células Dendríticas/inmunología , Infecciones por Herpesviridae/inmunología , Células Asesinas Naturales/inmunología , Muromegalovirus/inmunología , Animales , Antígenos CD11/biosíntesis , Citotoxicidad Inmunológica , Interferón-alfa/biosíntesis , Interferón gamma/biosíntesis , Interleucina-18 , Ligandos , Activación de Linfocitos , Ratones , Ratones Endogámicos BALB C , Subfamilia K de Receptores Similares a Lectina de Células NK , Receptores Inmunológicos/metabolismo , Receptores de Células Asesinas NaturalesRESUMEN
Antiviral immunity requires early and late mechanisms in which IFN-alpha and IL-12 play major roles. However, the initial events leading to their production remain largely unclear. Given the crucial role of TLR in innate recognition, we investigated their role in antiviral immunity in vivo. Upon murine CMV (MCMV) infection, both MyD88-/- and TLR9-/- mice were more susceptible and presented increased viral loads compared with C57BL/6, TLR2-/-, TLR3-/-, or TLR4-/- mice. However, in terms of resistance to infection, IFN-alpha production and in many other parameters of early inflammatory responses, the MyD88-/- mice showed a more defective response than TLR9-/- mice. In the absence of the TLR9/MyD88 signaling pathway, cytokine production was dramatically impaired with a complete abolition of bioactive IL-12p70 serum release contrasting with a high flexibility for IFN-alpha release, which is initially (36 h) plasmacytoid dendritic cell- and MyD88-dependent, and subsequently (44 h) PDC-, MyD88-independent and, most likely, TLR-independent. NK cells from MCMV-infected MyD88-/- and TLR9-/- mice displayed a severely impaired IFN-gamma production, yet retained enhanced cytotoxic activity. In addition, dendritic cell activation and critical inflammatory cell trafficking toward the liver were still effective. In the long term, except for isotype switching to MCMV-specific IgG1, the establishment of Ab responses was not significantly altered. Thus, our results demonstrate a critical requirement of TLR9 in the process of MCMV sensing to assure rapid antiviral responses, coordinated with other TLR-dependent and -independent events that are sufficient to establish adaptive immunity.
Asunto(s)
Proteínas Adaptadoras Transductoras de Señales/inmunología , Antígenos de Diferenciación/inmunología , Infecciones por Citomegalovirus/inmunología , Interferón-alfa/biosíntesis , Muromegalovirus/inmunología , Receptores Inmunológicos/inmunología , Proteínas Adaptadoras Transductoras de Señales/deficiencia , Proteínas Adaptadoras Transductoras de Señales/genética , Animales , Anticuerpos Antivirales/biosíntesis , Antígenos de Diferenciación/genética , Secuencia de Bases , Diferenciación Celular , Infecciones por Citomegalovirus/patología , Infecciones por Citomegalovirus/virología , Citotoxicidad Inmunológica , ADN Viral/genética , Células Dendríticas/clasificación , Células Dendríticas/inmunología , Células Dendríticas/patología , Femenino , Cambio de Clase de Inmunoglobulina , Interferón gamma/biosíntesis , Interleucina-12/biosíntesis , Células Asesinas Naturales/inmunología , Hígado/inmunología , Hígado/patología , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Muromegalovirus/genética , Muromegalovirus/patogenicidad , Factor 88 de Diferenciación Mieloide , Receptores Inmunológicos/deficiencia , Receptores Inmunológicos/genética , Receptor Toll-Like 2/deficiencia , Receptor Toll-Like 2/genética , Receptor Toll-Like 2/inmunología , Receptor Toll-Like 3/deficiencia , Receptor Toll-Like 3/genética , Receptor Toll-Like 3/inmunología , Receptor Toll-Like 4/deficiencia , Receptor Toll-Like 4/genética , Receptor Toll-Like 4/inmunología , Receptor Toll-Like 9/deficiencia , Receptor Toll-Like 9/genética , Receptor Toll-Like 9/inmunologíaRESUMEN
We report in this study the generation of a novel rat mAb that recognizes mouse plasmacytoid dendritic cells (pDC). This Ab, named 120G8, stains a small subset of CD11c(low) spleen cell with high specificity. This population produces high amounts of IFN-alpha upon in vitro viral stimulation. Both ex vivo- and in vitro-derived 120G8(+) cells display a phenotype identical with that of the previously described mouse pDC (B220(high)Ly6C(high)Gr1(low)CD11b(-)CD11c(low)). Mice treated with 120G8 mAb are depleted of B220(high)Ly6C(high)CD11c(low) cells and have a much-reduced ability to produce IFN-alpha in response to in vivo CpG stimulation. The mAb 120G8 stains all and only B220(high)Ly6C(high)CD11c(low) pDC in all lymphoid organs. Immunohistochemical studies performed with this mAb indicate that pDC are located in the T cell area of spleen, lymph nodes, and Peyer's patches. Although the Ag recognized by 120G8 is not yet known, we show that its expression is up-regulated by type I IFN on B cells and DC. Using this mAb in immunofluorescence studies demonstrates strain- and organ-specific differences in the frequency of pDC and other DC subsets. 129Sv mice have a much higher frequency of pDC, together with a lower frequency of conventional CD8alpha(+)CD11c(high) DC, compared with C57BL/6 mice, both in spleen and blood. The higher ability of 129Sv mice to produce IFN-alpha in vivo is related to a higher number of pDC, but also to a higher ability of pDC from 129Sv mice to produce IFN-alpha in vitro in response to viral stimulation.
Asunto(s)
Anticuerpos Monoclonales/metabolismo , Células Dendríticas/citología , Células Dendríticas/inmunología , Animales , Anticuerpos Bloqueadores/administración & dosificación , Anticuerpos Monoclonales/administración & dosificación , Anticuerpos Monoclonales/análisis , Anticuerpos Monoclonales/biosíntesis , Linfocitos B/inmunología , Linfocitos B/metabolismo , Células de la Médula Ósea/citología , Células de la Médula Ósea/inmunología , Células de la Médula Ósea/metabolismo , Antígeno CD11c/biosíntesis , Diferenciación Celular/inmunología , Células Cultivadas , Células Dendríticas/química , Células Dendríticas/metabolismo , Femenino , Inmunohistoquímica , Inmunofenotipificación , Interferón Tipo I/farmacología , Interferón gamma/antagonistas & inhibidores , Interferón gamma/biosíntesis , Antígenos Comunes de Leucocito/biosíntesis , Recuento de Leucocitos , Leucopenia/inmunología , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C3H , Ratones Endogámicos C57BL , Ratones Endogámicos CBA , Ratones Endogámicos DBA , Ratones Desnudos , Ratones SCID , Orthomyxoviridae/inmunología , Ratas , Especificidad de la Especie , Bazo/citología , Bazo/inmunología , Bazo/metabolismo , Coloración y Etiquetado , Regulación hacia Arriba/inmunologíaRESUMEN
In this study, using a soluble CD200-Ig fusion protein, we provide evidence that murine dendritic cells (DCs) possess a functional CD200R, whose engagement results in the reinforcement or appearance of immunosuppressive properties in these cells. In particular, the plasmacytoid subset (CD11c+B220+120G8+) of splenic DCs (pDCs) is induced by CD200-Ig to express the enzyme IDO, which initiates the tolerogenic pathway of tryptophan catabolism. As a result, pDCs are capable of suppressing Ag-specific responses in vivo when transferred into recipient hosts after treatment with CD200-Ig. IDO induction in pDCs through CD200R engagement requires type I IFNR signaling. Although the release of IFN-alpha may contribute to the full expression of CD200-Ig activity, autocrine IFN-alpha is unlikely to mediate alone the effects of CD200R engagement. These data prospect novel functions for both pDCs and the CD200-CD200R pair in the mouse. At the same time, these data underscore the possible unifying role of the IDO mechanism in immune tolerance.