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A multicenter cross-sectional diagnostic study was carried out including 45 children with nontuberculous mycobacterial cervicofacial lymphadenitis and controls. The tested immunoassay, detecting M. avium-specific anti-glycopeptidolipid-core immunoglobulin A antibodies, had inadequate diagnostic performance in the studied population and seems to be of no additional value in detecting cases of nontuberculous mycobacterial cervicofacial lymphadenitis.
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Background: Toll-like receptor (TLR) agonists have been investigated due to their potential dual effects as latency reverting agents and immune modulatory compounds in people living with HIV (PLWH). Here, we investigated whether co-stimulation of TLR7/8 agonists with RIG-I-like receptor (RLR) agonists enhances antiviral immunity. Methods: Peripheral blood mononuclear cells (PBMCs) and monocyte-derived dendritic cells (DCs) were incubated with TLR and RLR-agonists for 24 h and innate and adaptive immune responses were determined (maturation markers, cytokines in supernatant, ISG expression). Results: Both TLR7 and TLR8 agonists induced pro-inflammatory cytokines in DCs as well as PBMCs. TLR8 agonists were more potent in inducing cytokine responses and had a stronger effect on DC-induced immunity. Notably, while all compounds induced IL-12p70, co-stimulation with TLR8 agonists and RLR agonist polyI: C induced significantly higher levels of IL-12p70 in PBMCs. Moreover, crosstalk between TLR8 and RLR agonists induced a strong type I Interferon (IFN) response as different antiviral IFN-stimulated genes were upregulated by the combination compared to the agonists alone. Conclusion: Our data strongly suggest that TLR crosstalk with RLRs leads to strong antiviral immunity as shown by induction of IL-12 and type I IFN responses in contrast to TLRs alone. Thus, co-stimulation of TLRs and RLRs might be a powerful strategy to induce reactivation of latent reservoir as well as antiviral immunity that eliminates the reactivated cells.
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The non-pathogenic TH17 subset of helper T cells clears fungal infections, whereas pathogenic TH17 cells cause inflammation and tissue damage; however, the mechanisms controlling these distinct responses remain unclear. Here we found that fungi sensing by the C-type lectin dectin-1 in human dendritic cells (DCs) directed the polarization of non-pathogenic TH17 cells. Dectin-1 signaling triggered transient and intermediate expression of interferon (IFN)-ß in DCs, which was mediated by the opposed activities of transcription factors IRF1 and IRF5. IFN-ß-induced signaling led to integrin αvß8 expression directly and to the release of the active form of the cytokine transforming growth factor (TGF)-ß indirectly. Uncontrolled IFN-ß responses as a result of IRF1 deficiency induced high expression of the IFN-stimulated gene BST2 in DCs and restrained TGF-ß activation. Active TGF-ß was required for polarization of non-pathogenic TH17 cells, whereas pathogenic TH17 cells developed in the absence of active TGF-ß. Thus, dectin-1-mediated modulation of type I IFN responses allowed TGF-ß activation and non-pathogenic TH17 cell development during fungal infections in humans.
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Células Dendríticas , Interferón Tipo I , Micosis , Humanos , Citocinas/metabolismo , Células Dendríticas/metabolismo , Interferón Tipo I/metabolismo , Lectinas Tipo C/genética , Lectinas Tipo C/metabolismo , Células Th17/metabolismo , Factor de Crecimiento Transformador beta/metabolismo , Micosis/inmunologíaRESUMEN
New SARS-CoV-2 variants of concern and waning immunity demonstrate the need for a quick and simple prophylactic agent to prevent infection. Low molecular weight heparins (LMWH) are potent inhibitors of SARS-CoV-2 binding and infection in vitro. The airways are a major route for infection and therefore inhaled LMWH could be a prophylactic treatment against SARS-CoV-2. We investigated the efficacy of in vivo inhalation of LMWH in humans to prevent SARS-CoV-2 attachment to nasal epithelial cells in a single-center, open-label intervention study. Volunteers received enoxaparin in the right and a placebo (NaCl 0.9%) in the left nostril using a nebulizer. After application, nasal epithelial cells were retrieved with a brush for ex-vivo exposure to either SARS-CoV-2 pseudovirus or an authentic SARS-CoV-2 isolate and virus attachment as determined. LMWH inhalation significantly reduced attachment of SARS-CoV-2 pseudovirus as well as authentic SARS-CoV-2 to human nasal cells. Moreover, in vivo inhalation was as efficient as in vitro LMWH application. Cell phenotyping revealed no differences between placebo and treatment groups and no adverse events were observed in the study participants. Our data strongly suggested that inhalation of LMWH was effective to prevent SARS-CoV-2 attachment and subsequent infection. LMWH is ubiquitously available, affordable, and easy to apply, making them suitable candidates for prophylactic treatment against SARS-CoV-2. IMPORTANCE New SARS-CoV-2 variants of concern and waning immunity demonstrate the need for a quick and simple agent to prevent infection. Low molecular weight heparins (LMWH) have been shown to inhibit SARS-CoV-2 in experimental settings. The airways are a major route for SARS-CoV-2 infection and inhaled LMWH could be a prophylactic treatment. We investigated the efficacy of inhalation of the LMWH enoxaparin in humans to prevent SARS-CoV-2 attachment because this is a prerequisite for infection. Volunteers received enoxaparin in the right and a placebo in the left nostril using a nebulizer. Subsequently, nasal epithelial cells were retrieved with a brush and exposed to SARS-CoV-2. LMWH inhalation significantly reduced the binding of SARS-Cov-2 to human nasal cells. Cell phenotyping revealed no differences between placebo and treatment groups and no adverse events were observed in the participants. Our data indicated that LMWH can be used to block SARS-CoV-2 attachment to nasal cells. LMWH was ubiquitously available, affordable, and easily applicable, making them excellent candidates for prophylactic treatment against SARS-CoV-2.
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COVID-19 , Heparina de Bajo-Peso-Molecular , Humanos , Heparina de Bajo-Peso-Molecular/efectos adversos , SARS-CoV-2 , Enoxaparina/uso terapéuticoRESUMEN
The current pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and outbreaks of new variants highlight the need for preventive treatments. Here, we identified heparan sulfate proteoglycans as attachment receptors for SARS-CoV-2. Notably, neutralizing antibodies against SARS-CoV-2 isolated from COVID-19 patients interfered with SARS-CoV-2 binding to heparan sulfate proteoglycans, which might be an additional mechanism of antibodies to neutralize infection. SARS-CoV-2 binding to and infection of epithelial cells was blocked by low molecular weight heparins (LMWH). Although dendritic cells (DCs) and mucosal Langerhans cells (LCs) were not infected by SARS-CoV-2, both DC subsets efficiently captured SARS-CoV-2 via heparan sulfate proteoglycans and transmitted the virus to ACE2-positive cells. Notably, human primary nasal cells were infected by SARS-CoV-2, and infection was blocked by pre-treatment with LMWH. These data strongly suggest that heparan sulfate proteoglycans are important attachment receptors facilitating infection and transmission, and support the use of LMWH as prophylaxis against SARS-CoV-2 infection.
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COVID-19/transmisión , Proteoglicanos de Heparán Sulfato/metabolismo , Heparina de Bajo-Peso-Molecular/farmacología , SARS-CoV-2/patogenicidad , Enzima Convertidora de Angiotensina 2/inmunología , Enzima Convertidora de Angiotensina 2/metabolismo , Animales , Anticuerpos Neutralizantes/metabolismo , Anticuerpos Neutralizantes/farmacología , Chlorocebus aethiops , Células Dendríticas/metabolismo , Células Dendríticas/virología , Células Epiteliales/metabolismo , Células Epiteliales/virología , Interacciones Huésped-Patógeno , Humanos , Membrana Mucosa/citología , Membrana Mucosa/virología , SARS-CoV-2/metabolismo , Sindecano-1/metabolismo , Sindecano-4/metabolismo , Células Vero , Tratamiento Farmacológico de COVID-19RESUMEN
Semen is important in determining HIV-1 susceptibility but it is unclear how it affects virus transmission during sexual contact. Mucosal Langerhans cells (LCs) are the first immune cells to encounter HIV-1 during sexual contact and have a barrier function as LCs are restrictive to HIV-1. As semen from people living with HIV-1 contains complement-opsonized HIV-1, we investigated the effect of complement on HIV-1 dissemination by human LCs in vitro and ex vivo. Notably, pre-treatment of HIV-1 with semen enhanced LC infection compared to untreated HIV-1 in the ex vivo explant model. Infection of LCs and transmission to target cells by opsonized HIV-1 was efficiently inhibited by blocking complement receptors CR3 and CR4. Complement opsonization of HIV-1 enhanced uptake, fusion, and integration by LCs leading to an increased transmission of HIV-1 to target cells. However, in the absence of both CR3 and CR4, C-type lectin receptor langerin was able to restrict infection of complement-opsonized HIV-1. These data suggest that complement enhances HIV-1 infection of LCs by binding CR3 and CR4, thereby bypassing langerin and changing the restrictive nature of LCs into virus-disseminating cells. Targeting complement factors might be effective in preventing HIV-1 transmission.
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Infecciones por VIH/inmunología , VIH-1/fisiología , Células de Langerhans/inmunología , Semen/inmunología , Anticuerpos Bloqueadores/metabolismo , Antígenos CD/metabolismo , Línea Celular , Activación de Complemento , Transmisión de Enfermedad Infecciosa , Infecciones por VIH/transmisión , VIH-1/patogenicidad , Interacciones Huésped-Parásitos , Humanos , Evasión Inmune , Integrina alfaXbeta2/metabolismo , Lectinas Tipo C/metabolismo , Antígeno de Macrófago-1/metabolismo , Lectinas de Unión a Manosa/metabolismo , Opsonización , Semen/virologíaRESUMEN
Sexually transmitted Hepatitis C virus (HCV) infections and high reinfections are a major concern amongst men who have sex with men (MSM) living with HIV-1 and HIV-negative MSM. Immune activation and/or HIV-1 coinfection enhance HCV susceptibility via sexual contact, suggesting that changes in immune cells or external factors are involved in increased susceptibility. Activation of anal mucosal Langerhans cells (LCs) has been implicated in increased HCV susceptibility as activated but not immature LCs efficiently retain and transmit HCV to other cells. However, the underlying molecular mechanism of transmission remains unclear. Here we identified the Heparan Sulfate Proteoglycan Syndecan 4 as the molecular switch, controlling HCV transmission by LCs. Syndecan 4 was highly upregulated upon activation of LCs and interference with Heparan Sulfate Proteoglycans or silencing of Syndecan 4 abrogated HCV transmission. These data strongly suggest that Syndecan 4 mediates HCV transmission by activated LCs. Notably, our data also identified the C-type lectin receptor langerin as a restriction factor for HCV infection and transmission. Langerin expression abrogated HCV infection in HCV permissive cells, whereas langerin expression on the Syndecan 4 expressing cell line strongly decreased HCV transmission to a target hepatoma cell line. These data suggest that the balanced interplay between langerin restriction and Syndecan 4 transmission determines HCV dissemination. Silencing of langerin enhanced HCV transmission whereas silencing Syndecan 4 on activated LCs decreased transmission. Blocking Heparan Sulfate Proteoglycans abrogated HCV transmission by LCs ex vivo identifying Heparan Sulfate Proteoglycans and Syndecan 4 as potential targets to prevent sexual transmission of HCV. Thus, our data strongly suggest that the interplay between receptors promotes or restricts transmission and further indicate that Syndecan 4 is the molecular switch controlling HCV susceptibility after sexual contact.
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Antígenos CD/metabolismo , Infecciones por VIH/metabolismo , VIH-1/fisiología , Hepacivirus/fisiología , Hepatitis C/metabolismo , Células de Langerhans/fisiología , Lectinas Tipo C/metabolismo , Lectinas de Unión a Manosa/metabolismo , Enfermedades de Transmisión Sexual/metabolismo , Sindecano-4/metabolismo , Antígenos CD/genética , Diferenciación Celular , Línea Celular , Coinfección , Transmisión de Enfermedad Infecciosa , Homosexualidad Masculina , Humanos , Lectinas Tipo C/genética , Masculino , Lectinas de Unión a Manosa/genética , ARN Interferente Pequeño/genética , Sindecano-4/genética , Regulación hacia ArribaRESUMEN
Strong innate and adaptive immune responses are paramount in combating viral infections. Dendritic cells (DCs) detect viral infections via cytosolic RIG-I like receptors (RLRs) RIG-I and MDA5 leading to MAVS-induced immunity. The DEAD-box RNA helicase DDX3 senses abortive human immunodeficiency virus 1 (HIV-1) transcripts and induces MAVS-dependent type I interferon (IFN) responses, suggesting that abortive HIV-1 RNA transcripts induce antiviral immunity. Little is known about the induction of antiviral immunity by DDX3-ligand abortive HIV-1 RNA. Here we synthesized a 58 nucleotide-long capped RNA (HIV-1 Cap-RNA58) that mimics abortive HIV-1 RNA transcripts. HIV-1 Cap-RNA58 induced potent type I IFN responses in monocyte-derived DCs, monocytes, macrophages and primary CD1c+ DCs. Compared with RLR agonist poly-I:C, HIV-1 Cap-RNA58 induced comparable levels of type I IFN responses, identifying HIV-1 Cap-RNA58 as a potent trigger of antiviral immunity. In monocyte-derived DCs, HIV-1 Cap-RNA58 activated the transcription factors IRF3 and NF-κB. Moreover, HIV-1 Cap-RNA58 induced DC maturation and the expression of pro-inflammatory cytokines. HIV-1 Cap-RNA58-stimulated DCs induced proliferation of CD4+ and CD8+ T cells and differentiated naïve T helper (TH) cells toward a TH2 phenotype. Importantly, treatment of DCs with HIV-1 Cap-RNA58 resulted in an efficient antiviral innate immune response that reduced ongoing HIV-1 replication in DCs. Our data strongly suggest that HIV-1 Cap-RNA58 induces potent innate and adaptive immune responses, making it an interesting addition in vaccine design strategies.
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Inmunidad Adaptativa , Infecciones por VIH/inmunología , VIH-1/genética , Interacciones Microbiota-Huesped/inmunología , Inmunidad Innata , ARN Viral/farmacología , Diferenciación Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Células Cultivadas , Células Dendríticas/inmunología , Células Dendríticas/virología , Infecciones por VIH/virología , Humanos , Factor 3 Regulador del Interferón/metabolismo , Interferón Tipo I/metabolismo , Macrófagos/inmunología , Macrófagos/virología , Monocitos/inmunología , Monocitos/virología , FN-kappa B/metabolismo , ARN Viral/síntesis química , ARN Viral/inmunología , Transducción de Señal/efectos de los fármacos , Linfocitos T/efectos de los fármacos , Linfocitos T/inmunología , Transcripción GenéticaRESUMEN
The spirochete Borrelia miyamotoi has recently been shown to cause relapsing fever. Like the Lyme disease agent, Borrelia burgdorferi, B. miyamotoi is transmitted through the bite of infected ticks; however, little is known about the response of the immune system upon infection. Dendritic cells (DCs) play a central role in the early immune response against B. burgdorferi We investigated the response of DCs to two different strains of B. miyamotoi using in vitro and ex vivo models and compared this to the response elicited by B. burgdorferi. Our findings show that B. miyamotoi is phagocytosed by monocyte-derived DCs, causing upregulation of activation markers and production of proinflammatory cytokines in a similar manner to B. burgdorferi. Recognition of B. miyamotoi was demonstrated to be partially mediated by TLR2. DCs migrated out of human skin explants upon inoculation of the skin with B. miyamotoi. Finally, we showed that B. miyamotoi-stimulated DCs induced proliferation of naive CD4+ and CD8+ T cells to a larger extent than B. burgdorferi. In conclusion, we show in this study that DCs respond to and mount an immune response against B. miyamotoi that is similar to the response to B. burgdorferi and is able to induce T cell proliferation.
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Borrelia/fisiología , Células Dendríticas/inmunología , Mordeduras y Picaduras de Insectos/inmunología , Fiebre Recurrente/inmunología , Piel/patología , Linfocitos T/inmunología , Garrapatas/inmunología , Animales , Diferenciación Celular , Proliferación Celular , Células Cultivadas , Citocinas/metabolismo , Humanos , Mediadores de Inflamación/metabolismo , Activación de Linfocitos , Fagocitosis , Garrapatas/microbiología , Receptor Toll-Like 2/metabolismoRESUMEN
A single HIV-1 variant establishes infection of the host after sexual contact. Identifying the phenotypic characteristics of these Transmitted Founder (T/F) viruses is important to understand the restriction mechanisms during transmission. Langerhans cells (LCs) are the mucosal dendritic cell subset that has been shown to have a protective role in HIV-1 transmission. Immature LCs efficiently capture and degrade HIV-1 via langerin-mediated restriction. Here we have investigated the capacity of T/F HIV-1 strains to infect mucosal Langerhans cells (LCs). Notably, most T/F variants efficiently infected immature LCs derived from skin and vaginal tissue in contrast to chronic HIV-1 laboratory strains. Next we screened a panel of T/F viruses and their matched 6-month consensus sequence viruses. Interestingly most T/F variants infected immature LCs whereas donor-matched 6-month consensus sequence viruses had lost the ability to infect LCs. However, we also identified 6-month consensus sequence viruses that had retained an ability to infect LCs similar to that of the donor-matched T/F virus. Moreover, some T/F viruses and 6-month consensus sequence viruses were unable to infect immature LCs. Further analyses indicated that T/F viruses are less sensitive to langerin-mediated restriction. These data suggest that T/F HIV-1 variants have the ability to infect immature LCs, which will facilitate transmission.
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VIH-1/patogenicidad , Interacciones Huésped-Patógeno , Células de Langerhans/virología , Antígenos CD/metabolismo , Células Cultivadas , Células HEK293 , Humanos , Células de Langerhans/inmunología , Lectinas Tipo C/metabolismo , Lectinas de Unión a Manosa/metabolismoRESUMEN
Follicular T helper cells (TFH) are fundamental in orchestrating effective antibody-mediated responses critical for immunity against viral infections and effective vaccines. However, it is unclear how virus infection leads to TFH induction. We here show that dengue virus (DENV) infection of human dendritic cells (DCs) drives TFH formation via crosstalk of RIG-I-like receptor (RLR) RIG-I and MDA5 with type I Interferon (IFN) signaling. DENV infection leads to RLR-dependent IKKε activation, which phosphorylates IFNα/ß receptor-induced STAT1 to drive IL-27 production via the transcriptional complex ISGF3. Inhibiting RLR activation as well as neutralizing antibodies against IL-27 prevented TFH formation. DENV-induced CXCR5+PD-1+Bcl-6+ TFH cells secreted IL-21 and activated B cells to produce IgM and IgG. Notably, RLR activation by synthetic ligands also induced IL-27 secretion and TFH polarization. These results identify an innate mechanism by which antibodies develop during viral disease and identify RLR ligands as potent adjuvants for TFH-promoting vaccination strategies.
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Anticuerpos Antivirales/inmunología , Virus del Dengue/fisiología , Dengue/inmunología , Linfocitos T Colaboradores-Inductores/inmunología , Formación de Anticuerpos , Linfocitos B/inmunología , Proteína 58 DEAD Box/genética , Proteína 58 DEAD Box/inmunología , Células Dendríticas/inmunología , Dengue/genética , Dengue/virología , Humanos , Helicasa Inducida por Interferón IFIH1/genética , Helicasa Inducida por Interferón IFIH1/inmunología , Interleucina-27/genética , Interleucina-27/inmunología , Interleucinas/genética , Interleucinas/inmunología , Activación de Linfocitos , Receptores InmunológicosRESUMEN
Microbial DNA is highly immunostimulatory and is sensed by endosomal pattern recognition receptors after release from internalized microbes. It is unclear how extracellular DNA released from dead microbes is delivered to endosomal PRRs to induce immune responses. Here we have investigated the ability of DCs to bind and internalize extracellular E.coli DNA as well as synthetic DNA. DCs internalized E.coli and synthetic DNA, which was dependent on the C-type lectin receptor DC-SIGN. Notably, endosomal uptake of DNA by DCs enhanced TLR9-dependent responses of B cells against DNA. Hence, we have identified DC-SIGN as a cell surface receptor for DNA that facilitates immune responses directed against DNA.
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Linfocitos B/inmunología , Moléculas de Adhesión Celular/fisiología , ADN Bacteriano/inmunología , Células Dendríticas/inmunología , Escherichia coli/genética , Lectinas Tipo C/fisiología , Receptores de Superficie Celular/fisiología , Citocinas/biosíntesis , Humanos , Interferón Tipo I/biosíntesisRESUMEN
Dengue virus (DENV) causes 400 million infections annually and is one of several viruses that can cause viral hemorrhagic fever, which is characterized by uncontrolled immune activation resulting in high fever and internal bleeding. Although the underlying mechanisms are unknown, massive cytokine secretion is thought to be involved. Dendritic cells (DCs) are the main target cells of DENV, and we investigated their role in DENV-induced cytokine production and adaptive immune responses. DENV infection induced DC maturation and secretion of IL-1ß, IL-6, and TNF. Inhibition of DENV RNA replication abrogated these responses. Notably, silencing of RNA sensors RIG-I or MDA5 abrogated DC maturation, as well as cytokine responses by DENV-infected DCs. DC maturation was induced by type I IFN responses because inhibition of IFN-α/ß receptor signaling abrogated DENV-induced DC maturation. Moreover, DENV infection of DCs resulted in CCL2, CCL3, and CCL4 expression, which was abrogated after RIG-I and MDA5 silencing. DCs play an essential role in TH cell differentiation, and we show that RIG-I and MDA5 triggering by DENV leads to TH1 polarization, which is characterized by high levels of IFN-γ. Notably, cytokines IL-6, TNF, and IFN-γ and chemokines CCL2, CCL3, and CCL4 have been associated with disease severity, endothelial dysfunction, and vasodilation. Therefore, we identified RIG-I and MDA5 as critical players in innate and adaptive immune responses against DENV, and targeting these receptors has the potential to decrease hemorrhagic fever in patients.
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Proteína 58 DEAD Box/inmunología , Células Dendríticas/inmunología , Virus del Dengue/inmunología , Células TH1/inmunología , Diferenciación Celular , Quimiocina CCL2/genética , Quimiocina CCL2/inmunología , Quimiocina CCL3/genética , Quimiocina CCL3/inmunología , Quimiocina CCL4/genética , Quimiocina CCL4/inmunología , Proteína 58 DEAD Box/deficiencia , Proteína 58 DEAD Box/genética , Proteína 58 DEAD Box/metabolismo , Células Dendríticas/virología , Humanos , Helicasa Inducida por Interferón IFIH1/deficiencia , Helicasa Inducida por Interferón IFIH1/inmunología , Helicasa Inducida por Interferón IFIH1/metabolismo , Interferón gamma/inmunología , Interferón gamma/metabolismo , Interleucina-1beta/inmunología , Interleucina-1beta/metabolismo , Interleucina-6/inmunología , Interleucina-6/metabolismo , Receptores Inmunológicos , Células TH1/fisiología , Factor de Necrosis Tumoral alfa/inmunología , Factor de Necrosis Tumoral alfa/metabolismoRESUMEN
The mechanisms by which human immunodeficiency virus 1 (HIV-1) avoids immune surveillance by dendritic cells (DCs), and thereby prevents protective adaptive immune responses, remain poorly understood. Here we showed that HIV-1 actively arrested antiviral immune responses by DCs, which contributed to efficient HIV-1 replication in infected individuals. We identified the RNA helicase DDX3 as an HIV-1 sensor that bound abortive HIV-1 RNA after HIV-1 infection and induced DC maturation and type I interferon responses via the signaling adaptor MAVS. Notably, HIV-1 recognition by the C-type lectin receptor DC-SIGN activated the mitotic kinase PLK1, which suppressed signaling downstream of MAVS, thereby interfering with intrinsic host defense during HIV-1 infection. Finally, we showed that PLK1-mediated suppression of DDX3-MAVS signaling was a viral strategy that accelerated HIV-1 replication in infected individuals.
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Proteínas Adaptadoras Transductoras de Señales/metabolismo , Células Dendríticas/virología , Infecciones por VIH/inmunología , VIH-1/fisiología , Evasión Inmune , Inmunidad , Macrófagos/virología , Proteínas Adaptadoras Transductoras de Señales/genética , Extractos Celulares , Repeticiones Palindrómicas Cortas Agrupadas y Regularmente Espaciadas/genética , Estudios de Cohortes , ARN Helicasas DEAD-box/metabolismo , Células Dendríticas/inmunología , Regulación Viral de la Expresión Génica , Células HEK293 , Infecciones por VIH/virología , Interacciones Huésped-Patógeno/genética , Humanos , Interferón beta/sangre , Macrófagos/inmunología , Polimorfismo de Nucleótido Simple , ARN Viral/inmunología , ARN Viral/metabolismo , Receptores de Reconocimiento de Patrones/metabolismo , Transducción de Señal , Carga Viral/genéticaRESUMEN
Traditional medicines that stimulate or modulate the immune system can be used as innovative approaches to treat immunological diseases. The herbal medicine IMOD has been shown to strongly modulate immune responses in several animal studies as well as in clinical trials. However, little is known about the mechanisms of IMOD to modulate immunity. Here we have investigated whether IMOD modulates the immunological function of human dendritic cells (DCs). IMOD alone did not induce DC maturation nor production of cytokines. Notably, IMOD decreased the production of pro-inflammatory cytokines IL-6, IL-12 p70, and TNFα by LPS-activated DCs at both mRNA and protein levels in a dose dependent manner. In contrast, treatment with IMOD did not affect LPS induced-production of the anti-inflammatory cytokine IL-10. Furthermore, IMOD inhibited T cell activation/proliferation by LPS-treated DCs and skewed T-cells responses toward the T helper type 2 polarization. These data strongly indicate that IMOD has a potent immunomodulatory ability that affects TLR signaling and thereby modulates DC function. Insight into the immunomodulatory effect of herbal medicine IMOD may provide innovative strategies to affect the immune system and to help combat various diseases.
RESUMEN
Dendritic cells (DCs) orchestrate antibody-mediated responses to combat extracellular pathogens including parasites by initiating T helper cell differentiation. Here we demonstrate that carbohydrate-specific signalling by DC-SIGN drives follicular T helper cell (TFH) differentiation via IL-27 expression. Fucose, but not mannose, engagement of DC-SIGN results in activation of IKKε, which collaborates with type I IFNR signalling to induce formation and activation of transcription factor ISGF3. Notably, ISGF3 induces expression of IL-27 subunit p28, and subsequent IL-27 secreted by DC-SIGN-primed DCs is pivotal for the induction of Bcl-6(+)CXCR5(+)PD-1(hi)Foxp1(lo) TFH cells, IL-21 secretion by TFH cells and T-cell-dependent IgG production by B cells. Thus, we have identified an essential role for DC-SIGN-induced ISGF3 by fucose-based PAMPs in driving IL-27 and subsequent TFH polarization, which might be harnessed for vaccination design.
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Moléculas de Adhesión Celular/metabolismo , Células Dendríticas/citología , Fucosa/química , Subunidad gamma del Factor 3 de Genes Estimulados por el Interferón/metabolismo , Interleucina-27/metabolismo , Lectinas Tipo C/metabolismo , Receptores de Superficie Celular/metabolismo , Linfocitos T Colaboradores-Inductores/citología , Secuencias de Aminoácidos , Linfocitos B/citología , Diferenciación Celular , Núcleo Celular/metabolismo , Proteínas de Unión al ADN/metabolismo , Dimerización , Citometría de Flujo , Humanos , Inmunoglobulina G/química , Factor 7 Regulador del Interferón/metabolismo , Leucocitos Mononucleares/citología , Activación de Linfocitos/inmunología , Manosa/química , Proteínas Proto-Oncogénicas c-bcl-6 , Interferencia de ARN , Transducción de SeñalRESUMEN
Dendritic cells (DCs) are targets of measles virus (MV) and play central roles in viral dissemination. However, DCs express the RIG-I-like receptors (RLRs) RIG-I and Mda5 that sense MV and induce type I interferon (IFN) production. Given the potency of this antiviral response, RLRs are tightly regulated at various steps, including dephosphorylation by PP1 phosphatases, which induces their activation. We demonstrate that MV suppresses RIG-I and Mda5 by activating the C-type lectin DC-SIGN and inducing signaling that prevents RLR dephosphorylation. MV binding to DC-SIGN leads to activation of the kinase Raf-1, which induces the association of PP1 inhibitor I-1 with GADD34-PP1 holoenzymes, thereby inhibiting phosphatase activity. Consequently, GADD34-PP1 holoenzymes are unable to dephosphorylate RIG-I and Mda5, hence suppressing type I IFN responses and enhancing MV replication. Blocking DC-SIGN signaling allows RLR activation and suppresses MV infection of DCs. Thus, MV subverts DC-SIGN to control RLR activation and escape antiviral responses.
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Moléculas de Adhesión Celular/metabolismo , ARN Helicasas DEAD-box/metabolismo , Células Dendríticas/inmunología , Interacciones Huésped-Patógeno , Lectinas Tipo C/metabolismo , Virus del Sarampión/inmunología , Proteína Fosfatasa 1/antagonistas & inhibidores , Receptores de Superficie Celular/metabolismo , Línea Celular , Proteína 58 DEAD Box , Células Dendríticas/virología , Humanos , Evasión Inmune , Virus del Sarampión/fisiología , Receptores InmunológicosRESUMEN
Carbohydrate-specific signalling through DC-SIGN provides dendritic cells with plasticity to tailor immunity to the nature of invading microbes. Here we demonstrate that recognition of fucose-expressing extracellular pathogens like Schistosoma mansoni and Helicobacter pylori by DC-SIGN favors T helper cell type-2 (TH2) responses via activation of atypical NF-κB family member Bcl3. Crosstalk between TLR and DC-SIGN signalling results in TLR-induced MK2-mediated phosphorylation of LSP1, associated with DC-SIGN, upon fucose binding. Subsequently, IKKε and CYLD are recruited to phosphorylated LSP1. IKKε activation is pivotal for suppression of CYLD deubiquitinase activity and subsequent nuclear translocation of ubiquitinated Bcl3. Bcl3 activation represses TLR-induced proinflammatory cytokine expression, while enhancing interleukin-10 (IL-10) and TH2-attracting chemokine expression, shifting TH differentiation from TH1 to TH2 polarization. Thus, DC-SIGN directs adaptive TH2 immunity to fucose-expressing pathogens via an IKKε-CYLD-dependent signalling pathway leading to Bcl3 activation, which might be targeted in vaccination strategies or to prevent aberrant inflammation and allergy.
Asunto(s)
Moléculas de Adhesión Celular/metabolismo , Fucosa/metabolismo , Quinasa I-kappa B/metabolismo , Lectinas Tipo C/metabolismo , Proteínas Proto-Oncogénicas/metabolismo , Receptores de Superficie Celular/metabolismo , Transducción de Señal , Células Th2/inmunología , Factores de Transcripción/metabolismo , Proteínas Supresoras de Tumor/metabolismo , Animales , Proteínas del Linfoma 3 de Células B , Diferenciación Celular/efectos de los fármacos , Polaridad Celular/efectos de los fármacos , Quimiocinas/genética , Quimiocinas/metabolismo , Enzima Desubiquitinante CYLD , Regulación hacia Abajo/efectos de los fármacos , Activación Enzimática/efectos de los fármacos , Helicobacter pylori/inmunología , Humanos , Mediadores de Inflamación/metabolismo , Antígeno Lewis X/metabolismo , Lipopolisacáridos/farmacología , Proteínas de Microfilamentos/metabolismo , Modelos Biológicos , FN-kappa B/metabolismo , Fosforilación/efectos de los fármacos , Fosfoserina/metabolismo , Unión Proteica/efectos de los fármacos , ARN Mensajero/genética , ARN Mensajero/metabolismo , Schistosoma mansoni/inmunología , Transducción de Señal/efectos de los fármacos , Células Th2/efectos de los fármacos , Regulación hacia Arriba/efectos de los fármacosRESUMEN
Recognition of fungal pathogens by C-type lectin receptor (CLR) dectin-1 on human dendritic cells is essential for triggering protective antifungal TH1 and TH17 immune responses. We show that Fonsecaea monophora, a causative agent of chromoblastomycosis, a chronic fungal skin infection, evades these antifungal responses by engaging CLR mincle and suppressing IL-12, which drives TH1 differentiation. Dectin-1 triggering by F. monophora activates transcription factor IRF1, which is crucial for IL12A transcription via nucleosome remodeling. However, simultaneous F. monophora binding to mincle induces an E3 ubiquitin ligase Mdm2-dependent degradation pathway, via Syk-CARD9-mediated PKB signaling, that leads to loss of nuclear IRF1 activity, hence blocking IL12A transcription. The absence of IL-12 leads to impaired TH1 responses and promotes TH2 polarization. Notably, mincle is similarly exploited by other chromoblastomycosis-associated fungi to redirect TH responses. Thus, mincle is a fungal receptor that can suppress antifungal immunity and, as such, is a potential therapeutic target.