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BACKGROUND AND AIM: Obtaining, positioning and managing intravenous access is complex but common procedure in nursing care practice. Learning the right knowledge and skills during basic nurse education is an essential goal. The use of simulators allows for a better acquisition of skills, guaranteeing safety for patients and nursing students. However, the literature is still lacking on the use of simulation for intravenous cannulation procedures and device management, presenting few conflicting results. The aim of this study was to examine the effect of simulator-based learning on vascular access management in a population of nursing students. METHODS: Using comparative observational study design we evaluated the effect of simulator learning on vascular access management in a nursing student population. RESULTS: The differences between the scores at t1 between the groups of students are significant for obtaining vascular access with relative management of the device and intravenous therapy (t = 3.062, p = 0.001), while at t0, albeit with strong differences in scores means (t = 0.061, p = 0.871) are not statistically significant. Early use of the simulator is also fundamental over time (t = 5.362, p = 0.001). Furthermore, the satisfaction noted by the students during the clinical simulations improves with the increase in the number of the same, as it can influence the single performance. CONCLUSIONS: Nursing training based on the use of simulators favors a better acquisition of skills compared to traditional didactic.
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Cateterismo Periférico , Estudiantes de Enfermería , Humanos , Aprendizaje , Evaluación Educacional , Competencia Clínica , CatéteresRESUMEN
Children in refugee camps, and particularly those with disabilities, face unique challenges in accessing education and are at high risk of being marginalised. Best practices suggest that main-streaming is the optimal strategy for serving students with disabilities. This study examines the extent to which mainstreaming in a refugee camp helps to promote children's prosocial behaviours, taking into account their emotional and behavioural problems. In Kakuma Refugee Camp, Kenya, researchers collected data from the parents of children currently enrolled in special needs education centres (n=65) and from those formerly enrolled at these facilities who transitioned to mainstream classrooms (n=81). Children in mainstream schools functioned better in terms of prosocial behaviours, but this relationship disappeared when factoring in children's emotional and behavioural difficulties. In the context of a refugee camp, mainstreaming alone is not likely to help children's psychosocial and educational functioning, which requires dedicated supports, appropriate facilities and infrastructure, and a dual focus on disability-specific and disability-inclusive initiatives.
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Campos de Refugiados , Instituciones Académicas , Niño , Humanos , KeniaRESUMEN
Many refugee children face challenges accessing education, but refugee children with disabilities are especially vulnerable to exclusion from school environments as well as social settings. Mainstreaming is considered a best practice but may not always be feasible given the limited resources available in refugee camps. The purpose of this study is to examine the extent to which school setting (i.e., special needs vs. mainstream classrooms) is associated with changes in children's prosocial behaviors (i.e., social skills and ability to get along well with peers) and behavioral difficulties, accounting for disability status. In Kakuma Refugee Camp in Kenya, researchers collected two waves of data (approximately 2.5 years apart) for students enrolled in special needs schools (n = 78) and students who had transitioned from special needs schools into mainstream classrooms (n = 51). Children's average prosocial scores decreased between wave 1 and wave 2, but scores from children in special needs schools decreased at a lower rate indicating potential protective factors in these settings. While children's average total difficulties decreased over time, children's difficulties in special needs schools decreased at a faster rate, also indicating potential protective factors. Neither severity of disability nor gender significantly predicted change in prosocial or difficulties scores. In the context of a refugee camp, mainstreaming alone may not fully address the needs of children with disabilities. Specific factors seen in special education settings, such as individualized services, accessible accommodations, and infrastructure supports, must be considered as a means of creating inclusive educational environments.
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(1) Background-The five-year overall survival (OS) of muscle-invasive bladder cancer (MIBC) with neoadjuvant chemotherapy and cystectomy is around 50%. There is no validated biomarker to guide the treatment decision. We investigated whether the Immunoscore (IS) could predict the pathologic response to neoadjuvant chemotherapy and survival outcomes. (2) Methods-This retrospective study evaluated the IS in 117 patients treated using neoadjuvant chemotherapy for localized MIBC from six centers (France and Greece). Pre-treatment tumor samples were immunostained for CD3+ and CD8+ T cells and quantified to determine the IS. The results were associated with the response to neoadjuvant chemotherapy, time to recurrence (TTR), and OS. (3) Results-Low (IS-0), intermediate (IS-1-2), and high (IS-3-4) ISs were observed in 36.5, 43.7, and 19.8% of the cohort, respectively. IS was positively associated with a pathologic complete response (pCR; p-value = 0.0096). A high IS was found in 35.7% of patients with a pCR, whereas it was found in 11.3% of patients without a pCR. A low IS was observed in 48.4% of patients with no pCR and in 21.4% of patients with a pCR. Low-, intermediate-, and high-IS patients had five-year recurrence-free rates of 37.2%, 36.5%, and 72.6%, respectively. In the multivariable analysis, a high IS was associated with a prolonged TTR (high vs. low: p = 0.0134) and OS (high vs. low: p = 0.011). (4) Conclusions-This study showed the significant prognostic and predictive roles of IS regarding localized MIBC.
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Yellow fever virus (YFV) is an RNA virus primarily targeting the liver. Severe YF cases are responsible for hemorrhagic fever, plausibly precipitated by excessive proinflammatory cytokine response. Pathogen recognition receptors (PRRs), such as the cytoplasmic retinoic acid inducible gene I (RIG-I)-like receptors (RLRs), and the viral RNA sensor protein kinase R (PKR), are known to initiate a proinflammatory response upon recognition of viral genomes. Here, we sought to reveal the main determinants responsible for the acute cytokine expression occurring in human hepatocytes following YFV infection. Using a RIG-I-defective human hepatoma cell line, we found that RIG-I largely contributes to cytokine secretion upon YFV infection. In infected RIG-I-proficient hepatoma cells, RIG-I was localized in stress granules. These granules are large aggregates of stalled translation preinitiation complexes known to concentrate RLRs and PKR and are so far recognized as hubs orchestrating RNA virus sensing. Stable knockdown of PKR in hepatoma cells revealed that PKR contributes to both stress granule formation and cytokine induction upon YFV infection. However, stress granule disruption did not affect the cytokine response to YFV infection, as assessed by small interfering RNA (siRNA)-knockdown-mediated inhibition of stress granule assembly. Finally, no viral RNA was detected in stress granules using a fluorescence in situ hybridization approach coupled with immunofluorescence. Our findings suggest that both RIG-I and PKR mediate proinflammatory cytokine induction in YFV-infected hepatocytes, in a stress granule-independent manner. Therefore, by showing the uncoupling of the cytokine response from the stress granule formation, our model challenges the current view in which stress granules are required for the mounting of the acute antiviral response.IMPORTANCE Yellow fever is a mosquito-borne acute hemorrhagic disease caused by yellow fever virus (YFV). The mechanisms responsible for its pathogenesis remain largely unknown, although increased inflammation has been linked to worsened outcome. YFV targets the liver, where it primarily infects hepatocytes. We found that two RNA-sensing proteins, RIG-I and PKR, participate in the induction of proinflammatory mediators in human hepatocytes infected with YFV. We show that YFV infection promotes the formation of cytoplasmic structures, termed stress granules, in a PKR- but not RIG-I-dependent manner. While stress granules were previously postulated to be essential platforms for immune activation, we found that they are not required for the production of proinflammatory mediators upon YFV infection. Collectively, our work uncovered molecular events triggered by the replication of YFV, which could prove instrumental in clarifying the pathogenesis of the disease, with possible repercussions for disease management.
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Proteína 58 DEAD Box/metabolismo , Virus de la Fiebre Amarilla/metabolismo , eIF-2 Quinasa/metabolismo , Proteínas Adaptadoras Transductoras de Señales/genética , Animales , Carcinoma Hepatocelular , Línea Celular , Línea Celular Tumoral , Citocinas/metabolismo , Proteína 58 DEAD Box/deficiencia , Proteína 58 DEAD Box/genética , ADN Helicasas/genética , Técnicas de Silenciamiento del Gen , Haplorrinos , Hepatocitos/virología , Humanos , Proteínas de Unión a Poli-ADP-Ribosa/genética , ARN Helicasas/genética , Proteínas con Motivos de Reconocimiento de ARN/genética , ARN Interferente Pequeño , ARN Viral/genética , Proteínas de Unión al ARN/genética , Receptores Inmunológicos , Antígeno Intracelular 1 de las Células T/genética , Transcriptoma , eIF-2 Quinasa/genéticaRESUMEN
The international American Joint Committee on Cancer/Union for International Cancer Control (AJCC/UICC) tumour-node-metastasis (TNM) staging system provides the current guidelines for the classification of cancer. However, among patients within the same stage, the clinical outcome can be very different. More recently, a novel definition of cancer has emerged, implicating at all stages a complex and dynamic interaction between tumour cells and the immune system. This has enabled the definition of the immune contexture, representing the pre-existing immune parameters associated with patient survival. Even so, the role of distinct immune cell types in modulating cancer progression is increasingly emerging. An immune-based assay named the 'Immunoscore' was defined to quantify the in situ T cell infiltrate and was demonstrated to be superior to the AJCC/UICC TNM classification for patients with colorectal cancer. This Review provides a broad overview of the main immune parameters positively or negatively shaping cancer development, including the Immunoscore, and their prognostic and predictive value. The importance of the immune system in cancer control is demonstrated by the requirement for a pre-existing intratumour adaptive immune response for effective immunotherapies, such as checkpoint inhibitors. Finally, we discuss how the combination of multiple immune parameters, rather than individual ones, might increase prognostic and/or predictive power.
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Sistema Inmunológico/inmunología , Neoplasias/inmunología , Índice de Severidad de la Enfermedad , Antineoplásicos Inmunológicos/farmacología , Antineoplásicos Inmunológicos/uso terapéutico , Biomarcadores de Tumor/análisis , Neoplasias Colorrectales/diagnóstico , Neoplasias Colorrectales/etiología , Neoplasias Colorrectales/terapia , Progresión de la Enfermedad , Humanos , Inhibidores de Puntos de Control Inmunológico/farmacología , Inhibidores de Puntos de Control Inmunológico/uso terapéutico , Sistema Inmunológico/efectos de los fármacos , Sistema Inmunológico/fisiopatología , Inmunoensayo , Estadificación de Neoplasias , Neoplasias/diagnóstico , Neoplasias/etiología , Neoplasias/terapia , Valor Predictivo de las Pruebas , Pronóstico , Medición de Riesgo , Análisis de Supervivencia , Resultado del TratamientoRESUMEN
Colorectal cancer (CRC) represents a major public health challenges, with one of the highest incidences worldwide. The two affected anatomical sites in CRC, i.e. the colon and the rectum, share important underlying features, but often differ in terms of therapeutic management. Current guidelines for CRC define its clinical stratification according to classical, tumor cell-based and pathological parameters. Novel ground-breaking findings in the recent years revealed the prominent role of the immune system in shaping CRC development. This chapter provides a detailed overview of the main genomic and immune features driving (or hampering) CRC progression, with a focus on the main immune cells and factors shaping its evolution. Furthermore, we discuss how tumor-infiltrating immunity could be leveraged both for therapeutic and stratification purposes.
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Colon/inmunología , Neoplasias Colorrectales/inmunología , Linfocitos Infiltrantes de Tumor/inmunología , Recto/inmunología , Colon/patología , Progresión de la Enfermedad , Humanos , Recto/patologíaRESUMEN
Cancer is a complex disease whose outcome depends largely on the cross-talk between the tumor and its microenvironment. Here, we review the evolution of the field of tumor immunology and the advances, in lockstep, of our understanding of cancer as a disease. We discuss the involvement of different immune cells at distinct stages of tumor progression and how immune contexture determinants shaping tumor development are being exploited therapeutically. Current clinical stratification schemes focus on the tumor histopathology and the molecular characteristics of the tumor cell. We argue for the importance of revising these stratification systems to include immune parameters so as to address the immediate need for improved prognostic and/or predictive information to guide clinical decisions.
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Inmunoterapia/métodos , Neoplasias/inmunología , Neoplasias/terapia , Antígeno B7-H1/antagonistas & inhibidores , Antígeno CTLA-4/antagonistas & inhibidores , Humanos , Neoplasias/patología , Receptor de Muerte Celular Programada 1/antagonistas & inhibidores , Linfocitos T/inmunología , Microambiente Tumoral/inmunologíaRESUMEN
Tumors evolve in close interaction with their microenvironment, which encompasses a continual tension between the developing tumor and the host immune system. Clinical trials have shown that appropriate enhancement of a tumor immune response can lead to long-lasting clinical responses and patient benefit. Understanding the contribution of the immune contexture, in addition to the molecular subtype across different tumor indications, is a significant knowledge gap with limited sagacity to drive rational immunotherapy combinations. To better inform clinical studies, we must first strive to understand the multifaceted elements of the tumor-immune interaction, the spatiotemporal interplay of numerous different immune cell types, in conjunction with an understanding of the oncogenic drivers and mutations that may lead to presentation of neoepitopes and could drive changes within the tumor microenvironment. In this review, we discuss the Immunoscore and its probable universal characteristic. The overlay of immune quantification with the molecular segments of disease and how this may benefit identification of patients at high risk of tumor recurrence will be discussed. The Immunoscore may translate to provide a tumor agnostic method to define immune fitness of a given tumor and predict and stratify patients who will benefit from certain therapies (in particular immune therapies) and, ultimately, help save the lives of patients with cancer.
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Biomarcadores de Tumor/inmunología , Neoplasias del Colon/tratamiento farmacológico , Neoplasias del Colon/inmunología , Inmunoterapia/métodos , Mutación , Microambiente Tumoral , Neoplasias del Colon/genética , Neoplasias del Colon/patología , Humanos , PronósticoRESUMEN
Immunotherapies are the most rapidly growing drug class and have a major impact in oncology and on human health. It is increasingly clear that the effectiveness of immunomodulatory strategies depends on the presence of a baseline immune response and on unleashing of pre-existing immunity. Therefore, a general consensus emerged on the central part played by effector T cells in the antitumour responses. Recent technological, analytical and mechanistic advances in immunology have enabled the identification of patients who are more likely to respond to immunotherapy. In this Review, we focus on defining hot, altered and cold tumours, the complexity of the tumour microenvironment, the Immunoscore and immune contexture of tumours, and we describe approaches to treat such tumours with combination immunotherapies, including checkpoint inhibitors. In the upcoming era of combination immunotherapy, it is becoming critical to understand the mechanisms responsible for hot, altered or cold immune tumours in order to boost a weak antitumour immunity. The impact of combination therapy on the immune response to convert an immune cold into a hot tumour will be discussed.
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Vacunas contra el Cáncer/uso terapéutico , Inmunoterapia/métodos , Terapia Molecular Dirigida , Neoplasias/terapia , Microambiente Tumoral/efectos de los fármacos , Animales , Terapia Combinada , Humanos , Neoplasias/inmunología , Microambiente Tumoral/inmunologíaRESUMEN
Treatment of metastatic colorectal cancer is based upon the assumption that metastases are homogeneous within a patient. We quantified immune cell types of 603 whole-slide metastases and primary colorectal tumors from 222 patients. Primary lesions, and synchronous and metachronous metastases, had a heterogeneous immune infiltrate and mutational diversity. Small metastases had frequently a low Immunoscore and T and B cell score, while a high Immunoscore was associated with a lower number of metastases. Anti-epidermal growth factor receptor treatment modified immune gene expression and significantly increased T cell densities in the metastasis core. The predictive accuracy of the Immunoscore from a single biopsy was superior to the one of programmed cell death ligand 1 (PD-L1). The immune phenotype of the least-infiltrated metastasis had a stronger association with patient outcome than other metastases.
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Antineoplásicos/farmacología , Neoplasias Colorrectales/tratamiento farmacológico , Receptores ErbB/antagonistas & inhibidores , Linfocitos Infiltrantes de Tumor/efectos de los fármacos , Microambiente Tumoral/efectos de los fármacos , Adulto , Anciano , Anciano de 80 o más Años , Antígeno B7-H1/genética , Antígeno B7-H1/inmunología , Antígeno B7-H1/metabolismo , Estudios de Cohortes , Neoplasias Colorrectales/genética , Neoplasias Colorrectales/inmunología , Receptores ErbB/inmunología , Receptores ErbB/metabolismo , Femenino , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Regulación Neoplásica de la Expresión Génica/inmunología , Ontología de Genes , Redes Reguladoras de Genes , Humanos , Estimación de Kaplan-Meier , Linfocitos Infiltrantes de Tumor/inmunología , Linfocitos Infiltrantes de Tumor/metabolismo , Masculino , Persona de Mediana Edad , Metástasis de la Neoplasia , Microambiente Tumoral/genética , Microambiente Tumoral/inmunologíaRESUMEN
We examined how the immune microenvironment molds tumor evolution at different metastatic organs in a longitudinal dataset of colorectal cancer. Through multiplexed analyses, we showed that clonal evolution patterns during metastatic progression depend on the immune contexture at the metastatic site. Genetic evidence of neoantigen depletion was observed in the sites with high Immunoscore and spatial proximity between Ki67+ tumor cells and CD3+ cells. The immunoedited tumor clones were eliminated and did not recur, while progressing clones were immune privileged, despite the presence of tumor-infiltrating lymphocytes. Characterization of immune-privileged metastases revealed tumor-intrinsic and tumor-extrinsic mechanisms of escape. The lowest recurrence risk was associated with high Immunoscore, occurrence of immunoediting, and low tumor burden. We propose a parallel selection model of metastatic progression, where branched evolution could be traced back to immune-escaping clones. The findings could inform the understanding of cancer dissemination and the development of immunotherapeutics.
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Infiltración Leucémica/inmunología , Modelos Estadísticos , Neoplasias/inmunología , Carga Tumoral/inmunología , Humanos , Linfocitos Infiltrantes de Tumor/inmunología , Metástasis de la Neoplasia , Neoplasias/genética , Neoplasias/patología , Microambiente Tumoral/inmunologíaRESUMEN
IL-27 is a cytokine exerting pleiotropic immunomodulatory effects on a broad spectrum of immune cells. Optimal IL-27 production downstream of TLR3/4 ligand stimulation relies on autocrine type I IFN signaling, defining a first and second phase in IL-27 production. This work shows that IL-1 receptor-associated kinase 1 (IRAK1) limits TLR3/4- and IFNAR-induced IL-27 production. At the mechanistic level, we identified IRAK1 as a novel regulator of STAT1, IRF1, and IRF9. We found hyperactivation of STAT1 together with increased nuclear levels of IRF1 and IRF9 in IRAK1-deficient murine macrophages compared with control cells following stimulation with LPS and poly(I:C). IRAK1-deficient human microglial cells showed higher basal levels of STAT1 and STAT2 compared with control cells. Blocking the kinase activity of TBK1/IKKε in IRAK1 knockdown human microglial cells reduced the high basal levels of STAT1/2, uncovering a TBK1/IKKε kinase-dependent mechanism controlling basal levels of STAT1/2. Stimulating IRAK1 knockdown human microglial cells with IFN-ß led to increased IL-27p28 expression compared with control cells. In IRAK1-deficient murine macrophages, increased IL-27 levels were detected by ELISA following IFN-ß stimulation compared with control macrophages together with increased nuclear levels of p-STAT1, IRF1, and IRF9. Treatment of wild-type and IRAK1-deficient murine macrophages with fludarabine similarly reduced TLR3/4-induced IL-27 cytokine levels. To our knowledge, this work represents the first report placing IRAK1 in the IFNAR pathway and identifies IRAK1 as an important regulator of STAT1, controlling IL-27 production downstream of TLR3/4 and IFNAR signaling pathways.
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Quinasas Asociadas a Receptores de Interleucina-1/metabolismo , Interleucina-27/metabolismo , Macrófagos/metabolismo , Microglía/metabolismo , Receptor de Interferón alfa y beta/metabolismo , Animales , Células HEK293 , Humanos , Factor 3 de Genes Estimulados por el Interferón/metabolismo , Quinasas Asociadas a Receptores de Interleucina-1/genética , Ratones , Fosforilación , Receptor de Interferón alfa y beta/genética , Factor de Transcripción STAT1/metabolismo , Transducción de Señal , Receptor Toll-Like 3/metabolismo , Receptor Toll-Like 4/metabolismoRESUMEN
Plasmacytoid dendritic cells (pDCs) are specialized in the production of interferons (IFNs) in response to viral infections. The Flaviviridae family comprises enveloped RNA viruses such as Hepatitis C virus (HCV) and Dengue virus (DENV). Cell-free flaviviridae virions poorly stimulate pDCs to produce IFN. By contrast, cells infected with HCV and DENV potently stimulate pDCs via short-range delivery of viral RNAs, which are either packaged within immature virions or secreted exosomes. We report that cells infected with Yellow fever virus (YFV), the prototypical flavivirus, stimulated pDCs to produce IFNs in a TLR7- and cell contact- dependent manner. Such stimulation was unaffected by the presence of YFV neutralizing antibodies. As reported for DENV, cells producing immature YFV particles were more potent at stimulating pDCs than cells releasing mature virions. Additionally, cells replicating a release-deficient YFV mutant or a YFV subgenomic RNA lacking structural protein-coding sequences participated in pDC stimulation. Thus, viral RNAs produced by YFV-infected cells reach pDCs via at least two mechanisms: within immature particles and as capsid-free RNAs. Our work highlights the ability of pDCs to respond to a variety of viral RNA-laden carriers generated from infected cells.
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Cápside , Células Dendríticas/inmunología , Interferones/metabolismo , ARN Viral/metabolismo , Virión/inmunología , Fiebre Amarilla/inmunología , Virus de la Fiebre Amarilla/inmunología , Adulto , Anciano , Células Cultivadas , Células Dendríticas/metabolismo , Células Dendríticas/virología , Femenino , Humanos , Masculino , Persona de Mediana Edad , ARN Viral/genética , Virión/metabolismo , Fiebre Amarilla/metabolismo , Fiebre Amarilla/virología , Adulto JovenRESUMEN
Attenuated measles virus (MV) is currently being evaluated in clinical trials as an oncolytic therapeutic agent. Originally used for its lytic activity against tumor cells, it is now admitted that the effectiveness of MV also lies in its ability to initiate antitumor immune responses through the activation of dendritic cells (DCs). In this study, we investigated the capacity of oncolytic MV to convert human blood myeloid CD1c+ DCs and plasmacytoid DCs (pDCs) into cytotoxic effectors. We found that MV induces the expression of the cytotoxic protein TNF-related apoptosis-inducing ligand (TRAIL) on the surface of DCs. We demonstrate that the secretion of interferon-α (IFN-α) by DCs in response to MV is responsible for this TRAIL expression. Several types of PRRs (pattern recognition receptors) have been implicated in MV genome recognition, including RLRs (RIG-I-like receptors) and TLRs (Toll-like receptors). We showed that CD1c+ DCs secrete modest amounts of IFN-α and express TRAIL in an RLR-dependent manner upon exposure to MV. In pDCs, MV is recognized by RLRs and also by TLR7, leading to the secretion of high amounts of IFN-α and TRAIL expression. Finally, we showed that MV-stimulated DCs induce TRAIL-mediated cell death of Jurkat cells, confirming their acquisition of cytotoxic functions. Our results demonstrate that MV can activate cytotoxic myeloid CD1c+ DCs and pDCs, which may participate to the antitumor immune response.
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Although plasmacytoid dendritic cells (pDCs) represent a rare immune cell type, they are the most important source of type I interferons (IFNs) upon viral infection. Phagocytosed RNA viruses and RNA virus-infected cells are detected by pDCs with the endosomal pattern recognition receptor (PRR) toll-like receptor 7 (TLR7). We showed that replication of the yellow fever live vaccine YF-17D in human pDCs and pDC-like cell lines stimulated type I IFN production through RIG-I (retinoic acid-inducible gene I), a member of the RIG-I-like receptor (RLR) family of cytosolic PRRs. Thus, human pDCs sense replicative viral RNA. In contrast, direct contact between pDCs and YF-17D-infected cells stimulated a TLR7-dependent, viral replication-independent production of type I IFN. We also showed that the RLR pathway was dampened by the activities of interleukin-1 receptor-associated kinases 1 and 4 (IRAK1 and IRAK4), which are downstream effectors of the TLR7 pathway, suggesting that both kinases play opposing roles downstream of specific PRRs. Together, these data suggest that a virus can stimulate either TLR or RLR signaling in the same cell, depending on how its nucleic acid content is delivered.
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Células Dendríticas/metabolismo , Interferón Tipo I/metabolismo , Células Plasmáticas/metabolismo , ARN Viral/biosíntesis , Replicación Viral/fisiología , Virus de la Fiebre Amarilla/fisiología , Adulto , Animales , Chlorocebus aethiops , Proteína 58 DEAD Box , ARN Helicasas DEAD-box/metabolismo , Células Dendríticas/patología , Células Dendríticas/virología , Femenino , Humanos , Masculino , Células Plasmáticas/patología , Células Plasmáticas/virología , Receptores Inmunológicos , Receptor Toll-Like 7/metabolismo , Células Vero , Internalización del VirusRESUMEN
BACKGROUND: Human Immunodeficiency Virus-type 2 (HIV-2) encodes Vpx that degrades SAMHD1, a cellular restriction factor active in non-dividing cells. HIV-2 replicates in lymphocytes but the susceptibility of monocyte-derived dendritic cells (MDDCs) to in vitro infection remains partly characterized. RESULTS: Here, we investigated HIV-2 replication in primary CD4+ T lymphocytes, both activated and non-activated, as well as in MDDCs. We focused on the requirement of Vpx for productive HIV-2 infection, using the reference HIV-2 ROD strain, the proviral clone GL-AN, as well as two primary HIV-2 isolates. All HIV-2 strains tested replicated in activated CD4+ T cells. Unstimulated CD4+ T cells were not productively infected by HIV-2, but viral replication was triggered upon lymphocyte activation in a Vpx-dependent manner. In contrast, MDDCs were poorly infected when exposed to HIV-2. HIV-2 particles did not potently fuse with MDDCs and did not lead to efficient viral DNA synthesis, even in the presence of Vpx. Moreover, the HIV-2 strains tested were not efficiently sensed by MDDCs, as evidenced by a lack of MxA induction upon viral exposure. Virion pseudotyping with VSV-G rescued fusion, productive infection and HIV-2 sensing by MDDCs. CONCLUSION: Vpx allows the non-productive infection of resting CD4+ T cells, but does not confer HIV-2 with the ability to efficiently infect MDDCs. In these cells, an entry defect prevents viral fusion and reverse transcription independently of SAMHD1. We propose that HIV-2, like HIV-1, does not productively infect MDDCs, possibly to avoid triggering an immune response mediated by these cells.
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Linfocitos T CD4-Positivos/virología , Células Dendríticas/virología , VIH-2/fisiología , Internalización del Virus , Replicación Viral , Células Cultivadas , Humanos , Proteínas Reguladoras y Accesorias Virales/metabolismoRESUMEN
IRAK1 is involved in the regulation of type I IFN production downstream of TLR3. Previous work indicated that IRAK1 negatively regulates TRIF-mediated activation of IRF3 and IRF7. We report that IRAK1 limits the activation of the TLR3-NF-κB pathway. Following TLR3 stimulation, IRAK1-deficient macrophages produced increased levels of IL-6 and IFN-ß compared with wild type macrophages. Pharmacological inhibition of TAK1 reduced this increase in IFN-ß, together with the heightened activation of IRF3 and p65 found in TLR3-ligand stimulated IRAK1-deficient macrophages. Recently, IKKε and TANK-binding kinase 1 (TBK1) were reported to limit activation of the NF-κB pathway downstream of IL-1R, TNFR1, and TLRs. We show that TBK1 has a positive role in the TLR3-NF-κB pathway, because we detected reduced levels of IL-6 and reduced activation of p65 in TBK1-deficient macrophages. In contrast, we show that IKKε limits the activation of the TLR3-NF-κB pathway. Furthermore, we show that IRAK1 is required for the activation of IKKε downstream of TLR3. We report impaired activation of ERK1/2 in IRAK1- and IKKε-deficient macrophages, a novel finding for both kinases. Importantly, this work provides novel mechanistic insight into the regulation of the TLR3-signaling pathway, providing strong evidence that an IRAK1-IKKε-signaling axis acts to limit the production of both type I IFNs and proinflammatory cytokines by regulating TAK1 activity.