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Understanding the molecular pathways driving the acute antiviral and inflammatory response to SARS-CoV-2 infection is critical for developing treatments for severe COVID-19. Here, we find decreasing number of circulating plasmacytoid dendritic cells (pDCs) in COVID-19 patients early after symptom onset, correlating with disease severity. pDC depletion is transient and coincides with decreased expression of antiviral type I IFNα and of systemic inflammatory cytokines CXCL10 and IL-6. Using an in vitro stem cell-based human pDC model, we further demonstrate that pDCs, while not supporting SARS-CoV-2 replication, directly sense the virus and in response produce multiple antiviral (interferons: IFNα and IFNλ1) and inflammatory (IL-6, IL-8, CXCL10) cytokines that protect epithelial cells from de novo SARS-CoV-2 infection. Via targeted deletion of virus-recognition innate immune pathways, we identify TLR7-MyD88 signaling as crucial for production of antiviral interferons (IFNs), whereas Toll-like receptor (TLR)2 is responsible for the inflammatory IL-6 response. We further show that SARS-CoV-2 engages the receptor neuropilin-1 on pDCs to selectively mitigate the antiviral interferon response, but not the IL-6 response, suggesting neuropilin-1 as potential therapeutic target for stimulation of TLR7-mediated antiviral protection.
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COVID-19 , Células Dendríticas , Receptor Toll-Like 2 , Receptor Toll-Like 7 , COVID-19/inmunología , COVID-19/patología , Citocinas/metabolismo , Células Dendríticas/inmunología , Células Dendríticas/patología , Humanos , Interferón Tipo I/inmunología , Interferón-alfa/inmunología , Interleucina-6/inmunología , Neuropilina-1/inmunología , SARS-CoV-2 , Receptor Toll-Like 2/inmunología , Receptor Toll-Like 7/inmunologíaRESUMEN
BACKGROUND/AIMS: Immune cells are reported to upregulate CD47 during infection, however, the role of CD47 in innate and adaptive immune cells remains unclear. METHODS: To bridge this knowledge gap, we analysed our single cell (sc)-RNA dataset along with other publicly available sc-RNA datasets from healthy controls, people with HIV-1 (PWH) and COVID-19 patients. We characterized each immune cell based on low, intermediate, and high expression of CD47 . RESULTS: Our analyses revealed that CD47 high pDCs and monocytes exhibited relatively higher expression of IFN-α regulatory genes, antiviral interferon-stimulated genes (ISGs) and MHC-I associated genes compared to CD47 inter. and CD47 low cells. Furthermore, CD47 high NK and CD8+ T cells showed higher expression of antiviral ISGs, as well as genes encoding for cytotoxic markers like granzyme B, perforin, granulysin, interferon gamma and NKG7. Additionally, CD47 high CD8+ T cells expressed higher levels of PD-1 and LAG-3 genes. Lastly, we found that CD47 high B cells had enriched expression of genes involved in cell activation and humoral responses. CONCLUSION: Overall, our analyses revealed that innate and adaptive immune cells expressing elevated activation and functional gene signatures also express higher CD47 levels.
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Antígeno CD47 , Linfocitos T CD8-positivos , Granzimas , VIH-1 , Células Asesinas Naturales , Perforina , Receptor de Muerte Celular Programada 1 , ARN Mensajero , Análisis de la Célula Individual , Humanos , Antígeno CD47/metabolismo , Antígeno CD47/genética , Linfocitos T CD8-positivos/metabolismo , Linfocitos T CD8-positivos/inmunología , Granzimas/metabolismo , Granzimas/genética , Células Asesinas Naturales/inmunología , Células Asesinas Naturales/metabolismo , Perforina/metabolismo , Perforina/genética , VIH-1/inmunología , ARN Mensajero/metabolismo , ARN Mensajero/genética , Receptor de Muerte Celular Programada 1/metabolismo , Receptor de Muerte Celular Programada 1/genética , COVID-19/inmunología , COVID-19/virología , COVID-19/genética , Infecciones por VIH/inmunología , Infecciones por VIH/virología , Infecciones por VIH/genética , Proteína del Gen 3 de Activación de Linfocitos , Antígenos de Diferenciación de Linfocitos T/metabolismo , Antígenos de Diferenciación de Linfocitos T/genética , SARS-CoV-2/inmunología , Interferón gamma/metabolismo , Interferón gamma/genética , Monocitos/metabolismo , Monocitos/inmunología , Antígenos CD/metabolismo , Antígenos CD/genética , Linfocitos B/metabolismo , Linfocitos B/inmunología , Inmunidad InnataRESUMEN
Many immunological treatment strategies for reducing the HIV-1 reservoir and enhancing adaptive immunity aim at activating the human plasmacytoid dendritic cells (pDCs). Here, we present a protocol for pDC enrichment, single-cell analysis, and development of a pDC transcriptomic database from healthy individuals and people with HIV-1 before and after Toll-like receptor 9 agonist treatment. For complete details on the use and execution of this protocol, please refer to Cham et al.1.
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VIH-1 , Humanos , VIH-1/genética , Interferón-alfa , Inmunidad Adaptativa , Perfilación de la Expresión Génica , Células DendríticasRESUMEN
Human plasmacytoid dendritic cells (pDCs) play a central role in initiating and activating host immune responses during infection. To understand how the transcriptome of pDCs is impacted by HIV-1 infection and exogenous stimulation, we isolated pDCs from healthy controls, people with HIV-1 (PWH) before and during toll-like receptor 9 (TLR9) agonist treatment and performed single-cell (sc)-RNA sequencing. Our cluster analysis revealed four pDC clusters: pDC1, pDC2, cytotoxic-like pDC and an exhausted pDC cluster. The inducible cytotoxic-like pDC cluster is characterized by high expression of both antiviral and cytotoxic genes. Further analyses confirmed that cytotoxic-like pDCs are distinct from NK and T cells. Cell-cell communication analysis also demonstrated that cytotoxic-like pDCs exhibit similar incoming and outgoing cellular communicating signals as other pDCs. Thus, our study presents a detailed transcriptomic atlas of pDCs and provides new perspectives on the mechanisms of regulation and function of cytotoxic-like pDCs.
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Immune evasion is indispensable for cancer initiation and progression, although its underlying mechanisms in pancreatic ductal adenocarcinoma (PDAC) are not fully known. Here, we characterize the function of tumor-derived PGRN in promoting immune evasion in primary PDAC. Tumor- but not macrophage-derived PGRN is associated with poor overall survival in PDAC. Multiplex immunohistochemistry shows low MHC class I (MHCI) expression and lack of CD8+ T cell infiltration in PGRN-high tumors. Inhibition of PGRN abrogates autophagy-dependent MHCI degradation and restores MHCI expression on PDAC cells. Antibody-based blockade of PGRN in a PDAC mouse model remarkably decelerates tumor initiation and progression. Notably, tumors expressing LCMV-gp33 as a model antigen are sensitized to gp33-TCR transgenic T cell-mediated cytotoxicity upon PGRN blockade. Overall, our study shows a crucial function of tumor-derived PGRN in regulating immunogenicity of primary PDAC.
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Adenocarcinoma/genética , Carcinoma Ductal Pancreático/genética , Antígenos de Histocompatibilidad Clase I/genética , Neoplasias Pancreáticas/genética , Progranulinas/genética , Escape del Tumor/genética , Adenocarcinoma/inmunología , Adenocarcinoma/mortalidad , Adenocarcinoma/terapia , Animales , Anticuerpos Neutralizantes/farmacología , Antígenos Virales/genética , Antígenos Virales/inmunología , Autofagia/efectos de los fármacos , Autofagia/genética , Autofagia/inmunología , Linfocitos T CD8-positivos/efectos de los fármacos , Linfocitos T CD8-positivos/inmunología , Linfocitos T CD8-positivos/patología , Carcinoma Ductal Pancreático/inmunología , Carcinoma Ductal Pancreático/mortalidad , Carcinoma Ductal Pancreático/terapia , Línea Celular Tumoral , Movimiento Celular/efectos de los fármacos , Estudios de Cohortes , Citotoxicidad Inmunológica , Expresión Génica , Glicoproteínas/genética , Glicoproteínas/inmunología , Antígenos de Histocompatibilidad Clase I/inmunología , Humanos , Virus de la Coriomeningitis Linfocítica/genética , Virus de la Coriomeningitis Linfocítica/inmunología , Ratones , Neoplasias Pancreáticas/inmunología , Neoplasias Pancreáticas/mortalidad , Neoplasias Pancreáticas/terapia , Fragmentos de Péptidos/genética , Fragmentos de Péptidos/inmunología , Progranulinas/antagonistas & inhibidores , Progranulinas/inmunología , Proteolisis , Análisis de Supervivencia , Microambiente Tumoral/genética , Microambiente Tumoral/inmunología , Proteínas Virales/genética , Proteínas Virales/inmunología , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
An effective but balanced cellular and inflammatory immune response may limit the severity of coronavirus disease (COVID-19), whereas uncontrolled inflammation leads to disease progression. Older age is associated with higher risk of COVID-19 and a worse outcome, but the underlying immunological mechanisms for this age-related difference are not clear. We investigated the impact of age on viral replication, inflammation, and innate and adaptive cellular immune responses in 205 hospitalized COVID-19 patients. During the early symptomatic phase of COVID-19, we found that patients above 65 years had significantly higher viral load, higher levels of proinflammatory markers, and inadequate mobilization and activation of monocytes, dendritic cells, natural killer cells, and CD8 T cells compared to those below 65 years. Our study points toward age-related deficiencies in the innate immune cellular response to SARS-CoV-2 as a potential cause of poorly controlled viral replication and inflammation during the early symptom phase and subsequent disease progression.
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The integrin associated protein (CD47) is a widely and moderately expressed glycoprotein in all healthy cells. Cancer cells are known to induce increased CD47 expression. Similar to cancer cells, all immune cells can upregulate their CD47 surface expression during infection. The CD47-SIRPa interaction induces an inhibitory effect on macrophages and dendritic cells (dendritic cells) while CD47-thrombospondin-signaling inhibits T cells. Therefore, the disruption of the CD47 interaction can mediate several biologic functions. Upon the blockade and knockout of CD47 reveals an immunosuppressive effect of CD47 during LCMV, influenza virus, HIV-1, mycobacterium tuberculosis, plasmodium and other bacterial pneumonia infections. In our recent study we shows that the blockade of CD47 using the anti-CD47 antibody increases the activation and effector function of macrophages, dendritic cells and T cells during viral infection. By enhancing both innate and adaptive immunity, CD47 blocking antibody promotes antiviral effect. Due to its broad mode of action, the immune-stimulatory effect derived from this antibody could be applicable in nonresolving and (re)emerging infections. The anti-CD47 antibody is currently under clinical trial for the treatment of cancer and could also have amenable therapeutic potential against infectious diseases. This review highlights the immunotherapeutic targeted role of CD47 in the infectious disease realm.
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Ebola virus epidemics can be effectively limited by the VSV-EBOV vaccine (Ervebo) due to its rapid protection abilities; however, side effects prevent the broad use of VSV-EBOV as vaccine. Mechanisms explaining the efficient immune activation after single injection with the VSV-EBOV vaccine remain mainly unknown. Here, using the clinically available VSV-EBOV vaccine (Ervebo), we show that the cell-intrinsic expression of the interferon-inhibitor Usp18 in CD169+ macrophages is one important factor modulating the anti-Ebola virus immune response. The absence of Usp18 in CD169+ macrophages led to the reduced local replication of VSV-EBOV followed by a diminished innate as well as adaptive immune response. In line, CD169-Cre+/ki x Usp18fl/fl mice showed reduced innate and adaptive immune responses against the VSV wildtype strain and died quickly after infection, suggesting that a lack of Usp18 makes mice more susceptible to the side effects of the VSV vector. In conclusion, our study shows that Usp18 expression in CD169+ macrophages is one important surrogate marker for effective vaccination against VSV-EBOV, and probably other VSV-based vaccines also.
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The replication of virus in secondary lymphoid organs is crucial for the activation of antigen-presenting cells. Balanced viral replication ensures the sufficient availability of antigens and production of cytokines, and both of which are needed for virus-specific immune activation and viral elimination. Host factors that regulate coordinated viral replication are not fully understood. In the study reported here, we identified Map3k14 as an important regulator of enforced viral replication in the spleen while performing genome-wide association studies of various inbred mouse lines in a model of lymphocytic choriomeningitis virus (LCMV) infection. When alymphoplasia mice (aly/aly, Map3k14aly/aly, or Nikaly/aly), which carry a mutation in Map3k14, were infected with LCMV or vesicular stomatitis virus (VSV), they display early reductions in early viral replication in the spleen, reduced innate and adaptive immune activation, and lack of viral control. Histologically, scant B cells and the lack of CD169+ macrophages correlated with reduced immune activation in Map3k14aly/aly mice. The transfer of wildtype B cells into Map3k14aly/aly mice repopulated CD169+ macrophages, restored enforced viral replication, and resulted in enhanced immune activation and faster viral control.
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Paradoxically, early host responses to infection include the upregulation of the antiphagocytic molecule, CD47. This suggests that CD47 blockade could enhance antigen presentation and subsequent immune responses. Indeed, mice treated with anti-CD47 monoclonal antibody following lymphocytic choriomeningitis virus infections show increased activation of both macrophages and dendritic cells (DCs), enhancement of the kinetics and potency of CD8+ T cell responses, and significantly improved virus control. Treatment efficacy is critically dependent on both APCs and CD8+ T cells. In preliminary results from one of two cohorts of humanized mice infected with HIV-1 for 6 weeks, CD47 blockade reduces plasma p24 levels and restores CD4+ T cell counts. The results indicate that CD47 blockade not only enhances the function of innate immune cells but also links to adaptive immune responses through improved APC function. As such, immunotherapy by CD47 blockade may have broad applicability to treat a wide range of infectious diseases.
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Antígeno CD47/inmunología , Antígeno CD47/metabolismo , Virosis/inmunología , Inmunidad Adaptativa/inmunología , Animales , Linfocitos T CD8-positivos/inmunología , Línea Celular , Femenino , Células HEK293 , Humanos , Inmunidad Innata/inmunología , Inmunoterapia/métodos , Coriomeningitis Linfocítica/inmunología , Virus de la Coriomeningitis Linfocítica/inmunología , Macrófagos/inmunología , Ratones Endogámicos C57BL , Ratones Noqueados , Transducción de SeñalRESUMEN
Infections can result in a temporarily restricted unresponsiveness of the innate immune response, thereby limiting pathogen control. Mechanisms of such unresponsiveness are well studied in lipopolysaccharide tolerance; however, whether mechanisms of tolerance limit innate immunity during virus infection remains unknown. Here, we find that infection with the highly cytopathic vesicular stomatitis virus (VSV) leads to innate anergy for several days. Innate anergy is associated with induction of apoptotic cells, which activates the Tyro3, Axl, and Mertk (TAM) receptor Mertk and induces high levels of interleukin-10 (IL-10) and transforming growth factor ß (TGF-ß). Lack of Mertk in Mertk-/- mice prevents induction of IL-10 and TGF-ß, resulting in abrogation of innate anergy. Innate anergy is associated with enhanced VSV replication and poor survival after infection. Mechanistically, Mertk signaling upregulates suppressor of cytokine signaling 1 (SOCS1) and SOCS3. Dexamethasone treatment upregulates Mertk and enhances innate anergy in a Mertk-dependent manner. In conclusion, we identify Mertk as one major regulator of innate tolerance during infection with VSV.
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Anergia Clonal , Inmunidad Innata , Estomatitis Vesicular/enzimología , Estomatitis Vesicular/inmunología , Vesiculovirus/fisiología , Tirosina Quinasa c-Mer/metabolismo , Enfermedad Aguda , Animales , Antivirales/metabolismo , Muerte Celular/efectos de los fármacos , Anergia Clonal/efectos de los fármacos , Dexametasona/farmacología , Activación Enzimática/efectos de los fármacos , Inmunidad Innata/efectos de los fármacos , Interleucina-10/metabolismo , Ratones Endogámicos C57BL , Transducción de Señal/efectos de los fármacos , Estomatitis Vesicular/virologíaRESUMEN
Immune activation within the tumor microenvironment is one promising approach to induce tumor regression. Certain viruses including oncolytic viruses such as the herpes simplex virus (HSV) and non-oncolytic viruses such as the lymphocytic choriomeningitis virus (LCMV) are potent tools to induce tumor-specific immune activation. However, not all tumor types respond to viro- and/or immunotherapy and mechanisms accounting for such differences remain to be defined. In our current investigation, we used the non-cytopathic LCMV in different human melanoma models and found that melanoma cell lines produced high levels of CCL5 in response to immunotherapy. In vivo, robust CCL5 production in LCMV infected Ma-Mel-86a tumor bearing mice led to recruitment of NK cells and fast tumor regression. Lack of NK cells or CCL5 abolished the anti-tumoral effects of immunotherapy. In conclusion, we identified CCL5 and NK cell-mediated cytotoxicity as new factors influencing melanoma regression during virotherapy.
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Infecciones por Arenaviridae/inmunología , Quimiocina CCL5/inmunología , Inmunoterapia/métodos , Células Asesinas Naturales/inmunología , Melanoma/inmunología , Animales , Línea Celular Tumoral , Xenoinjertos , Humanos , Virus de la Coriomeningitis Linfocítica/inmunología , Ratones , Virus Oncolíticos/inmunologíaRESUMEN
It is well understood that the adaptive immune response to infectious agents includes a modulating suppressive component as well as an activating component. We now show that the very early innate response also has an immunosuppressive component. Infected cells upregulate the CD47 "don't eat me" signal, which slows the phagocytic uptake of dying and viable cells as well as downstream antigen-presenting cell (APC) functions. A CD47 mimic that acts as an essential virulence factor is encoded by all poxviruses, but CD47 expression on infected cells was found to be upregulated even by pathogens, including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), that encode no mimic. CD47 upregulation was revealed to be a host response induced by the stimulation of both endosomal and cytosolic pathogen recognition receptors (PRRs). Furthermore, proinflammatory cytokines, including those found in the plasma of hepatitis C patients, upregulated CD47 on uninfected dendritic cells, thereby linking innate modulation with downstream adaptive immune responses. Indeed, results from antibody-mediated CD47 blockade experiments as well as CD47 knockout mice revealed an immunosuppressive role for CD47 during infections with lymphocytic choriomeningitis virus and Mycobacterium tuberculosis Since CD47 blockade operates at the level of pattern recognition receptors rather than at a pathogen or antigen-specific level, these findings identify CD47 as a novel potential immunotherapeutic target for the enhancement of immune responses to a broad range of infectious agents.IMPORTANCE Immune responses to infectious agents are initiated when a pathogen or its components bind to pattern recognition receptors (PRRs). PRR binding sets off a cascade of events that activates immune responses. We now show that, in addition to activating immune responses, PRR signaling also initiates an immunosuppressive response, probably to limit inflammation. The importance of the current findings is that blockade of immunomodulatory signaling, which is mediated by the upregulation of the CD47 molecule, can lead to enhanced immune responses to any pathogen that triggers PRR signaling. Since most or all pathogens trigger PRRs, CD47 blockade could be used to speed up and strengthen both innate and adaptive immune responses when medically indicated. Such immunotherapy could be done without a requirement for knowing the HLA type of the individual, the specific antigens of the pathogen, or, in the case of bacterial infections, the antimicrobial resistance profile.
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Betacoronavirus/inmunología , Antígeno CD47/metabolismo , Inmunomodulación/inmunología , Receptores de Reconocimiento de Patrones/inmunología , Células A549 , Inmunidad Adaptativa/inmunología , Animales , Antígeno CD47/genética , Línea Celular Tumoral , Citocinas/inmunología , Femenino , Humanos , Inmunidad Innata/inmunología , Virus de la Coriomeningitis Linfocítica/inmunología , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Mycobacterium tuberculosis/inmunología , SARS-CoV-2 , Regulación hacia Arriba/inmunologíaRESUMEN
BACKGROUND: Tamoxifen (TAM) is an estrogen-receptor antagonist, widely used in the adjuvant treatment of early stage estrogen-sensitive breast cancer. Several studies have revealed new biological targets of TAM that mediate the estrogen receptor independent activities of the drug. Recently, the antiviral activity of TAM on replication of human immunodeficiency virus (HIV), hepatitis C virus (HCV) and Herpes simplex virus (HSV-1) in vitro was described. In the current study, we aimed to investigate the effect of TAM on infection with vesicular stomatitis virus (VSV). METHODS: Vero cells were treated with different concentrations of TAM for 24 h and then infected with VSV. Additionally, C57BL/6 mice were pretreated with 4 mg TAM, one day and three days before infection with VSV. Results: Treatment of Vero cells with TAM suppressed the viral replication of VSV in vitro and in vivo. The inhibitory effect of TAM on VSV replication correlated with an enhanced interferon-I response and stimulation of macrophages. Conclusions: TAM was identified as being capable to protect from VSV infection in vitro and in vivo. Consequently, this antiviral function (as an advantageous side-effect of TAM) might give rise to new clinical applications, such as treatment of resistant virus infections, or serve as an add-on to standard antiviral therapy.
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Splenic CD169+ macrophages are located in the marginal zone to efficiently capture blood-borne pathogens. Here, we investigate the requirements for the induction of CD8+ T cell responses by antigens (Ags) bound by CD169+ macrophages. Upon Ag targeting to CD169+ macrophages, we show that BATF3-dependent CD8α+ dendritic cells (DCs) are crucial for DNGR-1-mediated cross-priming of CD8+ T cell responses. In addition, we demonstrate that CD169, a sialic acid binding lectin involved in cell-cell contact, preferentially binds to CD8α+ DCs and that Ag transfer to CD8α+ DCs and subsequent T cell activation is dependent on the sialic acid-binding capacity of CD169. Finally, functional CD169 mediates optimal CD8+ T cell responses to modified vaccinia Ankara virus infection. Together, these data indicate that the collaboration of CD169+ macrophages and CD8α+ DCs for the initiation of effective CD8+ T cell responses is facilitated by binding of CD169 to sialic acid containing ligands on CD8α+ DCs.