RESUMO
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes coronavirus disease 2019 (COVID-19), which may result in acute respiratory distress syndrome (ARDS), multiorgan failure, and death. The alveolar epithelium is a major target of the virus, but representative models to study virus host interactions in more detail are currently lacking. Here, we describe a human 2D air-liquid interface culture system which was characterized by confocal and electron microscopy and single-cell mRNA expression analysis. In this model, alveolar cells, but also basal cells and rare neuroendocrine cells, are grown from 3D self-renewing fetal lung bud tip organoids. These cultures were readily infected by SARS-CoV-2 with mainly surfactant protein C-positive alveolar type II-like cells being targeted. Consequently, significant viral titers were detected and mRNA expression analysis revealed induction of type I/III interferon response program. Treatment of these cultures with a low dose of interferon lambda 1 reduced viral replication. Hence, these cultures represent an experimental model for SARS-CoV-2 infection and can be applied for drug screens.
Assuntos
Células Epiteliais Alveolares/metabolismo , COVID-19/metabolismo , Modelos Biológicos , Organoides/metabolismo , SARS-CoV-2/fisiologia , Replicação Viral , Células Epiteliais Alveolares/patologia , Células Epiteliais Alveolares/virologia , Animais , COVID-19/virologia , Chlorocebus aethiops , Regulação da Expressão Gênica , Humanos , Interferon Tipo I/biossíntese , Interferons/biossíntese , Organoides/patologia , Organoides/virologia , Células Vero , Interferon lambdaRESUMO
Mucins play an essential role in protecting the respiratory tract against microbial infections while also acting as binding sites for bacterial and viral adhesins. The heavily O-glycosylated gel-forming mucins MUC5AC and MUC5B eliminate pathogens by mucociliary clearance. Transmembrane mucins MUC1, MUC4, and MUC16 can restrict microbial invasion at the apical surface of the epithelium. In this study, we determined the impact of host mucins and mucin glycans on epithelial entry of SARS-CoV-2. Human lung epithelial Calu-3 cells express the SARS-CoV-2 entry receptor ACE2 and high levels of glycosylated MUC1, but not MUC4 and MUC16, on their cell surface. The O-glycan-specific mucinase StcE specifically removed the glycosylated part of the MUC1 extracellular domain while leaving the underlying SEA domain and cytoplasmic tail intact. StcE treatment of Calu-3 cells significantly enhanced infection with SARS-CoV-2 pseudovirus and authentic virus, while removal of terminal mucin glycans sialic acid and fucose from the epithelial surface did not impact viral entry. In Calu-3 cells, the transmembrane mucin MUC1 and ACE2 are located to the apical surface in close proximity and StcE treatment results in enhanced binding of purified spike protein. Both MUC1 and MUC16 are expressed on the surface of human organoid-derived air-liquid interface (ALI) differentiated airway cultures and StcE treatment led to mucin removal and increased levels of SARS-CoV-2 replication. In these cultures, MUC1 was highly expressed in non-ciliated cells while MUC16 was enriched in goblet cells. In conclusion, the glycosylated extracellular domains of different transmembrane mucins might have similar protective functions in different respiratory cell types by restricting SARS-CoV-2 binding and entry.
Assuntos
COVID-19 , Mucinas , Humanos , Mucinas/metabolismo , Enzima de Conversão de Angiotensina 2 , SARS-CoV-2/metabolismo , Antígeno Ca-125/metabolismo , Pulmão/metabolismo , PolissacarídeosRESUMO
Neutralizing antibodies are considered a correlate of protection against severe human respiratory syncytial virus (HRSV) disease. Currently, HRSV neutralization assays are performed on immortalized cell lines like Vero or A549 cells. It is known that assays on these cell lines exclusively detect neutralizing antibodies (nAbs) directed to the fusion (F) protein. For the detection of nAbs directed to the glycoprotein (G), ciliated epithelial cells expressing the cellular receptor CX3CR1 are required, but generation of primary cell cultures is expensive and labor-intensive. Here, we developed a high-throughput neutralization assay based on the interaction between clinically relevant HRSV grown on primary cells with ciliated epithelial cells, and validated this assay using a panel of infant sera. To develop the high-throughput neutralization assay, we established a culture of differentiated apical-out airway organoids (Ap-O AO). CX3CR1 expression was confirmed, and both F- and G-specific monoclonal antibodies neutralized HRSV in the Ap-O AO. In a side-by-side neutralization assay on Vero cells and Ap-O AO, neutralizing antibody levels in sera from 125 infants correlated well, although titers on Ap-O AO were consistently lower. We speculate that these lower titers might be an actual reflection of the neutralizing antibody capacity in vivo. The organoid-based neutralization assay described here holds promise for further characterization of correlates of protection against HRSV disease.
Assuntos
Anticorpos Neutralizantes , Receptor 1 de Quimiocina CX3C , Testes de Neutralização , Organoides , Infecções por Vírus Respiratório Sincicial , Vírus Sincicial Respiratório Humano , Humanos , Vírus Sincicial Respiratório Humano/imunologia , Anticorpos Neutralizantes/imunologia , Organoides/metabolismo , Organoides/imunologia , Organoides/virologia , Organoides/citologia , Animais , Testes de Neutralização/métodos , Chlorocebus aethiops , Células Vero , Infecções por Vírus Respiratório Sincicial/imunologia , Infecções por Vírus Respiratório Sincicial/virologia , Receptor 1 de Quimiocina CX3C/metabolismo , Receptor 1 de Quimiocina CX3C/imunologia , Anticorpos Antivirais/imunologia , Proteínas Virais de Fusão/imunologia , Proteínas Virais de Fusão/metabolismo , Lactente , Células Epiteliais/metabolismo , Células Epiteliais/imunologia , Células Epiteliais/virologia , Anticorpos Monoclonais/imunologiaRESUMO
The emergence of several bat coronavirus-related disease outbreaks in human and domestic animals has fueled surveillance of coronaviruses in bats worldwide. However, little is known about how these viruses interact with their natural hosts. We demonstrate a Betacoronavirus (subgenus Merbecovirus), PN-ßCoV, in the intestine of its natural host, Nathusius's Pipistrelle Bat (Pipistrellus nathusii), by combining molecular and microscopy techniques. Eighty-eight P. nathusii bat carcasses were tested for PN-ßCoV RNA by RT-qPCR, of which 25 bats (28%) tested positive. PN-ßCoV RNA was more often detected in samples of the intestinal tract than in other sample types. In addition, viral RNA loads were higher in intestinal samples compared to other sample types, both on average and in each individual bat. In one bat, we demonstrated Merbecovirus antigen and PN-ßCoV RNA expression in intestinal epithelium and the underlying connective tissue using immunohistochemistry and in situ hybridization, respectively. These results indicate that PN-ßCoV has a tropism for the intestinal epithelium of its natural host, Nathusius's Pipistrelle Bat, and imply that the fecal-oral route is a possible route of transmission. IMPORTANCE Virtually all mammal species circulate coronaviruses. Most of these viruses will infect one host species; however, coronaviruses are known to include species that can infect multiple hosts, for example the well-known virus that caused a pandemic, SARS-CoV-2. Chiroptera (bats) include over 1,400 different species, which are expected to harbor a great variety of coronaviruses. However, we know very little about how any of these coronaviruses interact with their bat hosts; for example, we do not know their modes of transmissions, or which cells they infect. Thus, we have a limited understanding of coronavirus infections in this important host group. The significance of our study is that we learned that a bat coronavirus that occurs in a common bat species in Europe has a tropism for the intestines. This implies the fecal-oral route is a likely transmission route.
Assuntos
COVID-19 , Quirópteros , Coronaviridae , Coronavírus da Síndrome Respiratória do Oriente Médio , Animais , Humanos , Filogenia , SARS-CoV-2 , Intestinos , Tropismo , RNARESUMO
SARS-CoV-2 can enter cells after its spike protein is cleaved by either type II transmembrane serine proteases (TTSPs), like TMPRSS2, or cathepsins. It is now widely accepted that the Omicron variant uses TMPRSS2 less efficiently and instead enters cells via cathepsins, but these findings have yet to be verified in more relevant cell models. Although we could confirm efficient cathepsin-mediated entry for Omicron in a monkey kidney cell line, experiments with protease inhibitors showed that Omicron (BA.1 and XBB1.5) did not use cathepsins for entry into human airway organoids and instead utilized TTSPs. Likewise, CRISPR-edited intestinal organoids showed that entry of Omicron BA.1 relied on the expression of the serine protease TMPRSS2 but not cathepsin L or B. Together, these data force us to rethink the concept that Omicron has adapted to cathepsin-mediated entry and indicate that TTSP inhibitors should not be dismissed as prophylactic or therapeutic antiviral strategy against SARS-CoV-2. IMPORTANCE Coronavirus entry relies on host proteases that activate the viral fusion protein, spike. These proteases determine the viral entry route, tropism, host range, and can be attractive drug targets. Whereas earlier studies using cell lines suggested that the Omicron variant of SARS-CoV-2 has changed its protease usage, from cell surface type II transmembrane serine proteases (TTSPs) to endosomal cathepsins, we report that this is not the case in human airway and intestinal organoid models, suggesting that host TTSP inhibition is still a viable prophylactic or therapeutic antiviral strategy against current SARS-CoV-2 variants and highlighting the importance of relevant human in vitro cell models.
Assuntos
Serina Proteases , Humanos , Antivirais , COVID-19/virologia , SARS-CoV-2/fisiologia , Serina Proteases/metabolismo , Glicoproteína da Espícula de Coronavírus/genética , Glicoproteína da Espícula de Coronavírus/metabolismo , Internalização do VírusRESUMO
Modified vaccinia virus Ankara (MVA) is used as a vaccine against monkeypox virus and as a viral vaccine vector. MVA-MERS-S is a vaccine candidate against Middle East respiratory syndrome (MERS)-associated coronavirus. Here, we report that cross-reactive monkeypox virus neutralizing antibodies were detectable in only a single study participant after the first dose of MVA-MERS-S vaccine, in 3 of 10 after the second dose, and in 10 of 10 after the third dose.
Assuntos
Infecções por Coronavirus , Coronavírus da Síndrome Respiratória do Oriente Médio , Vacinas Virais , Humanos , Anticorpos Amplamente Neutralizantes , Glicoproteína da Espícula de Coronavírus , Monkeypox virus , Anticorpos Antivirais , Vaccinia virus/genética , Infecções por Coronavirus/prevenção & controle , Anticorpos NeutralizantesRESUMO
Middle East respiratory syndrome coronavirus (MERS-CoV) clade B viruses are found in camelids and humans in the Middle East, but clade C viruses are not. We provide experimental evidence for extended shedding of MERS-CoV clade B viruses in llamas, which might explain why they outcompete clade C strains in the Arabian Peninsula.
Assuntos
Camelídeos Americanos , Infecções por Coronavirus , Herpesvirus Cercopitecino 1 , Coronavírus da Síndrome Respiratória do Oriente Médio , Animais , Humanos , Eliminação de Partículas Virais , CamelusRESUMO
PURPOSE: To study the effect of interferon-α2 auto-antibodies (IFN-α2 Abs) on clinical and virological outcomes in critically ill COVID-19 patients and the risk of IFN-α2 Abs transfer during convalescent plasma treatment. METHODS: Sera from healthy controls, cases of COVID-19, and other respiratory illness were tested for IFN-α2 Abs by ELISA and a pseudo virus-based neutralization assay. The effects of disease severity, sex, and age on the risk of having neutralizing IFN-α2 Abs were determined. Longitudinal analyses were performed to determine association between IFN-α2 Abs and survival and viral load and whether serum IFN-α2 Abs appeared after convalescent plasma transfusion. RESULTS: IFN-α2 neutralizing sera were found only in COVID-19 patients, with proportions increasing with disease severity and age. In the acute stage of COVID-19, all sera from patients with ELISA-detected IFN-α2 Abs (13/164, 7.9%) neutralized levels of IFN-α2 exceeding physiological concentrations found in human plasma and this was associated with delayed viral clearance. Convalescent plasma donors that were anti-IFN-α2 ELISA positive (3/118, 2.5%) did not neutralize the same levels of IFN-α2. Neutralizing serum IFN-α2 Abs were associated with delayed viral clearance from the respiratory tract. CONCLUSIONS: IFN-α2 Abs were detected by ELISA and neutralization assay in COVID-19 patients, but not in ICU patients with other respiratory illnesses. The presence of neutralizing IFN-α2 Abs in critically ill COVID-19 is associated with delayed viral clearance. IFN-α2 Abs in COVID-19 convalescent plasma donors were not neutralizing in the conditions tested.
Assuntos
Autoanticorpos/imunologia , COVID-19/imunologia , COVID-19/terapia , Interferon alfa-2/imunologia , Plasma/imunologia , Adulto , Idoso , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Antivirais/imunologia , Transfusão de Componentes Sanguíneos/métodos , Estado Terminal , Feminino , Humanos , Imunização Passiva/métodos , Imunoglobulina G/imunologia , Masculino , Pessoa de Meia-Idade , SARS-CoV-2/imunologia , Soroterapia para COVID-19RESUMO
Effective clinical intervention strategies for coronavirus disease 2019 (COVID-19) are urgently needed. Although several clinical trials have evaluated use of convalescent plasma containing virus-neutralizing antibodies, levels of neutralizing antibodies are usually not assessed and the effectiveness has not been proven. We show that hamsters treated prophylactically with a 1:2560 titer of human convalescent plasma or a 1:5260 titer of monoclonal antibody were protected against weight loss, had a significant reduction of virus replication in the lungs, and showed reduced pneumonia. Interestingly, this protective effect was lost with a titer of 1:320 of convalescent plasma. These data highlight the importance of screening plasma donors for high levels of neutralizing antibodies. Our data show that prophylactic administration of high levels of neutralizing antibody, either monoclonal or from convalescent plasma, prevent severe SARS-CoV-2 pneumonia in a hamster model, and could be used as an alternative or complementary to other antiviral treatments for COVID-19.
Assuntos
Anticorpos Monoclonais/uso terapêutico , Anticorpos Neutralizantes/uso terapêutico , COVID-19/terapia , Pulmão/patologia , SARS-CoV-2/imunologia , Replicação Viral/efeitos dos fármacos , Animais , Anticorpos Monoclonais/administração & dosagem , Anticorpos Neutralizantes/administração & dosagem , COVID-19/imunologia , Cricetinae , Modelos Animais de Doenças , Humanos , Imunização Passiva , Pulmão/efeitos dos fármacos , Eliminação de Partículas Virais/efeitos dos fármacos , Redução de Peso/efeitos dos fármacos , Soroterapia para COVID-19RESUMO
A new coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has recently emerged to cause a human pandemic. Although molecular diagnostic tests were rapidly developed, serologic assays are still lacking, yet urgently needed. Validated serologic assays are needed for contact tracing, identifying the viral reservoir, and epidemiologic studies. We developed serologic assays for detection of SARS-CoV-2 neutralizing, spike protein-specific, and nucleocapsid-specific antibodies. Using serum samples from patients with PCR-confirmed SARS-CoV-2 infections, other coronaviruses, or other respiratory pathogenic infections, we validated and tested various antigens in different in-house and commercial ELISAs. We demonstrated that most PCR-confirmed SARS-CoV-2-infected persons seroconverted by 2 weeks after disease onset. We found that commercial S1 IgG or IgA ELISAs were of lower specificity, and sensitivity varied between the 2 assays; the IgA ELISA showed higher sensitivity. Overall, the validated assays described can be instrumental for detection of SARS-CoV-2-specific antibodies for diagnostic, seroepidemiologic, and vaccine evaluation studies.
Assuntos
Anticorpos Antivirais/sangue , Betacoronavirus/imunologia , Técnicas de Laboratório Clínico/métodos , Infecções por Coronavirus/diagnóstico , Pneumonia Viral/diagnóstico , COVID-19 , Teste para COVID-19 , Ensaio de Imunoadsorção Enzimática , Humanos , Testes de Neutralização , Pandemias , SARS-CoV-2 , Sensibilidade e Especificidade , Testes SorológicosRESUMO
Posttranslational modifications are central to the spatial and temporal regulation of protein function. Among others, phosphorylation and ubiquitylation are known to regulate proximal T-cell receptor (TCR) signaling. Here we used a systematic and unbiased approach to uncover deubiquitylating enzymes (DUBs) that participate during TCR signaling in primary mouse T lymphocytes. Using a C-terminally modified vinyl methyl ester variant of ubiquitin (HA-Ub-VME), we captured DUBs that are differentially recruited to the cytosol on TCR activation. We identified ubiquitin-specific peptidase (Usp) 12 and Usp46, which had not been previously described in this pathway. Stimulation with anti-CD3 resulted in phosphorylation and time-dependent translocation of Usp12 from the nucleus to the cytosol. Usp12(-/-) Jurkat cells displayed defective NFκB, NFAT, and MAPK activities owing to attenuated surface expression of TCR, which were rescued on reconstitution of wild type Usp12. Proximity-based labeling with BirA-Usp12 revealed several TCR adaptor proteins acting as interactors in stimulated cells, of which LAT and Trat1 displayed reduced expression in Usp12(-/-) cells. We demonstrate that Usp12 deubiquitylates and prevents lysosomal degradation of LAT and Trat1 to maintain the proximal TCR complex for the duration of signaling. Our approach benefits from the use of activity-based probes in primary cells without any previous genome modification, and underscores the importance of ubiquitin-mediated regulation to refine signaling cascades.
Assuntos
Membrana Celular/metabolismo , Receptores de Antígenos de Linfócitos T/metabolismo , Transdução de Sinais , Ubiquitina Tiolesterase/metabolismo , Animais , Sistemas CRISPR-Cas/genética , Núcleo Celular/metabolismo , Separação Celular , Citosol/metabolismo , Endopeptidases/metabolismo , Ácidos Graxos Insaturados/farmacologia , Humanos , Células Jurkat , Camundongos , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Modelos Biológicos , NF-kappa B/metabolismo , Fatores de Transcrição NFATC/metabolismo , Transporte Proteico , Reprodutibilidade dos Testes , Especificidade por Substrato/efeitos dos fármacos , Linfócitos T/metabolismo , Ubiquitina/metabolismo , Ubiquitina Tiolesterase/deficiência , Proteases Específicas de Ubiquitina/metabolismoRESUMO
Background: High-pathogenicity avian influenza viruses continue to circulate in poultry and wild birds and occasionally infect humans, sometimes with fatal outcomes. Development of vaccines is a priority to prepare for potential pandemics but is complicated by antigenic variation of the surface glycoprotein hemagglutinin. We report the immunological profile induced by human immunization with modified vaccinia virus Ankara (MVA) expressing the hemagglutinin gene of influenza A(H5N1) virus A/Vietnam/1194/04 (rMVA-H5). Methods: In a double-blinded phase 1/2a clinical trial, 79 individuals received 1 or 2 injections of rMVA-H5 or vector control. Twenty-seven study subjects received a booster immunization after 1 year. The breadth, magnitude, and properties of vaccine-induced antibody and T-cell responses were characterized. Results: rMVA-H5 induced broadly reactive antibody responses, demonstrated by protein microarray, hemagglutination inhibition, virus neutralization, and antibody-dependent cellular cytotoxicity assays. Antibodies cross-reacted with antigenically distinct H5 viruses, including the recently emerged subtypes H5N6 and H5N8 and the currently circulating subtype H5N1. In addition, the induction of T cells specific for H5 viruses of 2 different clades was demonstrated. Conclusions: rMVA-H5 induced immune responses that cross-reacted with H5 viruses of various clades. These findings validate rMVA-H5 as vaccine candidate against antigenically distinct H5 viruses. Clinical Trials Registration: NTR3401.
Assuntos
Anticorpos Antivirais/sangue , Glicoproteínas de Hemaglutininação de Vírus da Influenza/imunologia , Virus da Influenza A Subtipo H5N1/imunologia , Vacinas contra Influenza/imunologia , Influenza Humana/prevenção & controle , Linfócitos T/imunologia , Adulto , Citotoxicidade Celular Dependente de Anticorpos , Reações Cruzadas , Método Duplo-Cego , Portadores de Fármacos , Feminino , Testes de Inibição da Hemaglutinação , Glicoproteínas de Hemaglutininação de Vírus da Influenza/genética , Humanos , Esquemas de Imunização , Virus da Influenza A Subtipo H5N1/genética , Vacinas contra Influenza/administração & dosagem , Vacinas contra Influenza/genética , Masculino , Testes de Neutralização , Análise Serial de Proteínas , Vacinas Sintéticas/administração & dosagem , Vacinas Sintéticas/genética , Vacinas Sintéticas/imunologia , Vaccinia virus/genética , Adulto JovemRESUMO
It is well known that microbial pathogens and herbivores elicit defence responses in plants. Moreover, microorganisms associated with herbivores, such as bacteria or viruses, can modulate the plant's response to herbivores. Herbivorous spider mites can harbour different species of bacterial symbionts and exert a broad range of effects on host-plant defences. Hence, we tested the extent to which such symbionts affect the plant's defences induced by their mite host and assessed if this translates into changes in plant resistance. We assessed the bacterial communities of two strains of the common mite pest Tetranychus urticae. We found that these strains harboured distinct symbiotic bacteria and removed these using antibiotics. Subsequently, we tested to which extent mites with and without symbiotic bacteria induce plant defences in terms of phytohormone accumulation and defence gene expression, and assessed mite oviposition and survival as a measure for plant resistance. We observed that the absence/presence of these bacteria altered distinct plant defence parameters and affected mite performance but we did not find indications for a causal link between the two. We argue that although bacteria-related effects on host-induced plant defences may occur, these do not necessarily affect plant resistance concomitantly.
Assuntos
Bactérias/efeitos dos fármacos , Herbivoria , Solanum lycopersicum/microbiologia , Solanum lycopersicum/parasitologia , Simbiose , Tetranychidae/fisiologia , Animais , Antibacterianos/farmacologia , Feminino , Herbivoria/efeitos dos fármacos , Solanum lycopersicum/imunologia , Masculino , Movimento , Reguladores de Crescimento de Plantas/análise , Análise de Sobrevida , Simbiose/efeitos dos fármacos , Tetranychidae/efeitos dos fármacosRESUMO
We characterized Middle East respiratory syndrome coronaviruses from a hospital outbreak in Jordan in 2015. The viruses from Jordan were highly similar to isolates from Riyadh, Saudi Arabia, except for deletions in open reading frames 4a and 3. Transmissibility and pathogenicity of this strain remains to be determined.
Assuntos
Sequência de Bases , Infecções por Coronavirus/epidemiologia , Surtos de Doenças , Coronavírus da Síndrome Respiratória do Oriente Médio/genética , RNA Viral/genética , Deleção de Sequência , Adulto , Sequência de Aminoácidos , Infecções por Coronavirus/patologia , Infecções por Coronavirus/virologia , Feminino , Hospitais , Humanos , Jordânia/epidemiologia , Masculino , Pessoa de Meia-Idade , Coronavírus da Síndrome Respiratória do Oriente Médio/classificação , Coronavírus da Síndrome Respiratória do Oriente Médio/patogenicidade , Fases de Leitura Aberta , Filogenia , Arábia Saudita/epidemiologia , Alinhamento de Sequência , Proteínas Virais/genéticaRESUMO
Ferret coronaviruses (FRCoVs) exist as an enteric and a systemic pathotype, of which the latter is highly lethal to ferrets. To our knowledge, this study provides the first full genome sequence of a FRCoV, tentatively called FRCoV-NL-2010, which was detected in 2010 in ferrets in The Netherlands. Phylogenetic analysis showed that FRCoV-NL-2010 is most closely related to mink CoV, forming a separate clade of mustelid alphacoronavirus that split off early from other alphacoronaviruses. Based on sequence homology of the complete genome, we propose that these mustelid coronaviruses may be assigned to a new species. Comparison of FRCoV-NL-2010 with the partially sequenced ferret systemic coronavirus MSU-1 and ferret enteric coronavirus MSU-2 revealed that recombination in the spike, 3c and envelope genes occurred between different FRCoVs.
Assuntos
Infecções por Coronavirus/veterinária , Coronavirus/classificação , Coronavirus/isolamento & purificação , Furões/virologia , Genoma Viral , RNA Viral/genética , Recombinação Genética , Animais , Análise por Conglomerados , Coronavirus/genética , Infecções por Coronavirus/virologia , Países Baixos , Filogenia , Análise de Sequência de DNA , Homologia de SequênciaRESUMO
We obtained the full genome of Middle East respiratory syndrome coronavirus (MERS-CoV) from a camel in Qatar. This virus is highly similar to the human England/Qatar 1 virus isolated in 2012. The MERS-CoV from the camel efficiently replicated in human cells, providing further evidence for the zoonotic potential of MERS-CoV from camels.
Assuntos
Doenças dos Animais/epidemiologia , Doenças dos Animais/virologia , Camelus/virologia , Infecções por Coronavirus/veterinária , Coronavírus da Síndrome Respiratória do Oriente Médio/isolamento & purificação , Doenças dos Animais/história , Animais , Linhagem Celular , Genoma Viral , História do Século XXI , Humanos , Coronavírus da Síndrome Respiratória do Oriente Médio/classificação , Coronavírus da Síndrome Respiratória do Oriente Médio/genética , Dados de Sequência Molecular , Filogenia , Catar/epidemiologia , RNA Viral , Replicação ViralRESUMO
Human metapneumovirus (HMPV), a member of the Pneumoviridae family, causes upper and lower respiratory tract infections in humans. In vitro studies with HMPV have mostly been performed in monolayers of undifferentiated epithelial cells. In vivo studies in cynomolgus macaques and cotton rats have shown that ciliated epithelial cells are the main target of HMPV infection, but these observations cannot be studied in monolayer systems. Here, we established an organoid-derived bronchial culture model that allows physiologically relevant studies on HMPV. Inoculation with multiple prototype HMPV viruses and recent clinical virus isolates led to differences in replication among HMPV isolates. Prolific HMPV replication in this model caused damage to the ciliary layer, including cilia loss at advanced stages post-infection. These cytopathic effects correlated with those observed in previous in vivo studies with cynomolgus macaques. The assessment of the innate immune responses in three donors upon HMPV and RSV inoculation highlighted the importance of incorporating multiple donors to account for donor-dependent variation. In conclusion, these data indicate that the organoid-derived bronchial cell culture model resembles in vivo findings and is therefore a suitable and robust model for future HMPV studies. IMPORTANCE: Human metapneumovirus (HMPV) is one of the leading causative agents of respiratory disease in humans, with no treatment or vaccine available yet. The use of primary epithelial cultures that recapitulate the tissue morphology and biochemistry of the human airways could aid in defining more relevant targets to prevent HMPV infection. For this purpose, this study established the first primary organoid-derived bronchial culture model suitable for a broad range of HMPV isolates. These bronchial cultures were assessed for HMPV replication, cellular tropism, cytopathology, and innate immune responses, where the observations were linked to previous in vivo studies with HMPV. This study exposed an important gap in the HMPV field since extensively cell-passaged prototype HMPV B viruses did not replicate in the bronchial cultures, underpinning the need to use recently isolated viruses with a controlled passage history. These results were reproducible in three different donors, supporting this model to be suitable to study HMPV infection.
Assuntos
Metapneumovirus , Infecções por Paramyxoviridae , Humanos , Animais , Metapneumovirus/fisiologia , Citologia , Replicação Viral , Infecções por Paramyxoviridae/patologia , Epitélio , Macaca , TropismoRESUMO
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes coronavirus disease 2019 (COVID-19). Commonly used methods for both clinical diagnosis of SARS-CoV-2 infection and management of infected patients involve the detection of viral RNA, but the presence of infectious virus particles is unknown. Viability PCR (v-PCR) uses a photoreactive dye to bind non-infectious RNA, ideally resulting in the detection of RNA only from intact virions. This study aimed to develop and validate a rapid v-PCR assay for distinguishing intact and compromised SARS-CoV-2. Propidium monoazide (PMAxx) was used as a photoreactive dye. Mixtures with decreasing percentages of intact SARS-CoV-2 (from 100% to 0%) were prepared from SARS-CoV-2 virus stock and a clinical sample. Each sample was divided into a PMAxx-treated part and a non-PMAxx-treated part. Reverse transcription-PCR (RT-PCR) using an in-house developed SARS-CoV-2 viability assay was then applied to both sample sets. The difference in intact SARS-CoV-2 was determined by subtracting the cycle threshold (Ct) value of the PMAxx-treated sample from the non-PMAxx-treated sample. Mixtures with decreasing concentrations of intact SARS-CoV-2 showed increasingly lower delta Ct values as the percentage of intact SARS-CoV-2 decreased, as expected. This relationship was observed in both high and low viral load samples prepared from cultured SARS-CoV-2 virus stock, as well as for a clinical sample prepared directly from a SARS-CoV-2 positive nasopharyngeal swab. In this study, a rapid v-PCR assay has been validated that can distinguish intact from compromised SARS-CoV-2. The presence of intact virus particles, as determined by v-PCR, may indicate SARS-CoV-2 infectiousness. IMPORTANCE: This study developed a novel method that can help determine whether someone who has been diagnosed with coronavirus disease 2019 (COVID-19) is still capable of spreading the virus to others. Current tests only detect the presence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA, but cannot tell whether the particles are still intact and can thus infect cells. The researchers used a dye that selectively blocks the detection of damaged virions and free RNA. They showed that this viability PCR reliably distinguishes intact SARS-CoV-2 capable of infecting from damaged SARS-CoV-2 or free RNA in both cultured virus samples and a clinical sample. Being able to quickly assess contagiousness has important implications for contact tracing and safely ending isolation precautions. This viability PCR technique provides a simple way to obtain valuable information, beyond just positive or negative test results, about the actual risk someone poses of transmitting SARS-CoV-2 through the air or surfaces they come into contact with.
RESUMO
The conjunctival epithelium covering the eye contains two main cell types: mucus-producing goblet cells and water-secreting keratinocytes, which present mucins on their apical surface. Here, we describe long-term expanding organoids and air-liquid interface representing mouse and human conjunctiva. A single-cell RNA expression atlas of primary and cultured human conjunctiva reveals that keratinocytes express multiple antimicrobial peptides and identifies conjunctival tuft cells. IL-4/-13 exposure increases goblet and tuft cell differentiation and drastically modifies the conjunctiva secretome. Human NGFR+ basal cells are identified as bipotent conjunctiva stem cells. Conjunctival cultures can be infected by herpes simplex virus 1 (HSV1), human adenovirus 8 (hAdV8), and SARS-CoV-2. HSV1 infection was reversed by acyclovir addition, whereas hAdV8 infection, which lacks an approved drug therapy, was inhibited by cidofovir. We document transcriptional programs induced by HSV1 and hAdV8. Finally, conjunctival organoids can be transplanted. Together, human conjunctiva organoid cultures enable the study of conjunctival (patho)-physiology.