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The pathogenicity of SARS-CoV-2 in hACE2 transgenic mice

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Severe acute respiratory syndrome CoV-2 (SARS-CoV-2) caused the corona virus disease 2019 (COVID-19) cases in China and has become a public health emergency of international concern1. Because angiotensin-converting enzyme 2 (ACE2) is the cell entry receptor of SARS-CoV5, we used transgenic mice bearing human ACE2 and infected with SARS-CoV-2 to study the pathogenicity of the virus. Weight loss and virus replication in lung were observed in hACE2 mice infected with SARS-CoV-2. The typical histopathology was interstitial pneumonia with infiltration of significant macrophages and lymphocytes into the alveolar interstitium, and accumulation of macrophages in alveolar cavities. Viral antigens were observed in the bronchial epithelial cells, macrophages and alveolar epithelia. The phenomenon was not found in wild-type mice with SARS-CoV-2 infection. Notably, we have confirmed the pathogenicity of SARS-CoV-2 in hACE2 mice. The mouse model with SARS-CoV-2 infection will be valuable for evaluating antiviral therapeutics and vaccines as well as understanding the pathogenesis of COVID-19.
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830 | Nature | Vol 583 | 30 July 2020
The pathogenicity of SARS-CoV-2 in hACE2
transgenic mice
Linlin Bao1,2,6, Wei Deng1,2,6, Baoying Huang3,6, Hong Gao1,2,6, Jiangning Liu1,2,6, Lili Ren4,
Qiang Wei1,2, Pin Yu1,2, Yanfeng Xu1,2, Feifei Qi1,2, Yajin Qu1,2, Fengdi Li1,2, Qi Lv1,2, Wenling Wang3,
Jing Xue1,2, Shuran Gong1,2, Mingya Liu1,2, Guanpeng Wang1,2, Shunyi Wang1,2, Zhiqi Song1,2,
Linna Zhao1,2, Peipei Liu3, Li Zhao3, Fei Ye3, Huijuan Wang3, Weimin Zhou3, Na Zhu3, Wei Zhen3,
Haisheng Yu1,2, Xiaojuan Zhang1,2, Li Guo4, Lan Chen4, Conghui Wang4, Ying Wang4,
Xinming Wang4, Yan Xiao4, Qiangming Sun5, Hongqi Liu5, Fanli Zhu5, Chunxia Ma5,
Lingmei Yan5, Mengli Yang5, Jun Han3, Wenbo Xu3, Wenjie Tan3, Xiaozhong Peng5, Qi Jin4,
Guizhen Wu3 ✉ & Chuan Qin1,2 ✉
Severe acute respiratory syndrome coronavirus2 (SARS-CoV-2) is the cause of
coronavirus disease2019 (COVID-19), which has become a public health emergency of
international concern1. Angiotensin-converting enzyme2 (ACE2) is the cell-entry
receptor for severe acute respiratory syndrome coronavirus (SARS-CoV)2. Here we
infected transgenic mice that express human ACE2 (hereafter, hACE2mice) with
SARS-CoV-2 and studied the pathogenicity of the virus. We observed weight loss as
well as virus replication in the lungs of hACE2 mice infected with SARS-CoV-2. The
typical histopathology was interstitial pneumonia with inltration of considerable
numbers of macrophages and lymphocytes into the alveolar interstitium, and the
accumulation of macrophages in alveolar cavities. We obser ved viral antigens in
bronchial epithelial cells, macrophages and alveolar epithelia. These phenomena
were not found in wild-type mice infected with SARS-CoV-2. Notably, we have
conrmed the pathogenicity of SARS-CoV-2 in hACE2 mice. This mouse model of
SARS-CoV-2 infection will be valuable for evaluating antiviral therapeutic agents and
vaccines, as well as understanding the pathogenesis of COVID-19.
In late December 2019, cases of COVID-19—which is caused by
SARS-CoV-2—were identified and reported from Wuhan city (Hubei
province, China), where they were linked to a seafood market at
which exotic animals were also sold and consumed1,3. The number
of confirmed cases has since soared: as of 25 February 2020, almost
78,000cases and over 2,700deaths were reported in China4, and
imported cases from travellers from mainland China were reported
in several other countries. It is critical to establish the pathogenicity
and biology of the virus for prevention and treatment of the disease.
Because SARS-CoV-2 is highly homologous with SARS-CoV, human
ACE2—which is the entry receptor of SARS-CoV—was also considered to
have a high binding ability with the SARS-CoV-2 by molecular biological
analysis2,5. We therefore used transgenic hACE2 mice and wild-type mice
infected with the HB-01 strain of SARS-CoV-2 to study the pathogenic-
ity of the virus.
Specific-pathogen-free male and female wild-type (n=15) or hACE2
(n=19) mice of 6–11months of age were inoculated intranasally with
SARS-CoV-2 strain HB-01 at a dosage of 10
50% tissue culture infectious
dose (TCID50) per 50μl inoculum volume per mouse, after the mice were
intraperitoneally anaesthetized using 2.5% avertin; mock-treated hACE2
mice (n=15) were used as control. Clinical manifestations were recorded
from 13mice (3HB-01-infected wild-type mice; 3mock-treated hACE2
mice; and 7HB-01-infected hACE2 mice). We observed slight bristled
fur and weight loss only in the HB-01-infected hACE2 mice—and not the
HB-01-infected wild-type mice or mock-treated hACE2 mice—during
the 14days of observation; other clinical symptoms, such as an arched
back and decreased response of external stimuli, were not found in any
of the mice. Notably, the weight loss of HB-01-infected hACE2 mice was
up to 8% at 5days post-infection (dpi) (Fig.1a).
Next, we examined viral replication and pathological changes in three
mice per group at each time point; the primary organs—including heart,
liver, spleen, lung, kidney, brain, intestine and testis—were collected
periodically. As shown in Fig.1b, viral loads were detectable by quantita-
tive PCR with reverse transcription (RT–qPCR) at 1, 3, 5 and 7dpi in the
lungs of HB-01-infected hACE2 mice (but not in those of HB-01-infected
wild-type mice; data not shown), and viral RNA copies reached a peak
of 106.77 copies per ml at 3dpi. Viral RNA was also detectable at 1dpi in
the intestine of HB-01-infected hACE2 mice, which was not detected
in other tissues along the timeline (Fig.1b). Although viral loads were
detectable in the intestine, no virus in the intestine was isolated at
1dpi; we therefore speculate that the viral load detected was residual
input inoculum from the nasal mucosa transferred to the intestines by
Received: 2 February 2020
Accepted: 24 April 2020
Published online: 7 May 2020
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1Beijing Key Laboratory for Animal Models of Emerging and Remerging Infectious Diseases, Institute of Laboratory Animal Science, Chinese Academy of Medical Sciences, Beijing, China. 2NHC
Key Laboratory of Human Disease Comparative Medicine, Comparative Medicine Center, Peking Union Medical College, Beijing, China. 3MHC Key Laboratory of Biosafety, National Institute for
Viral Disease Control and Prevention, China CDC, Beijing, China. 4Institute of Pathogen Biology, Chinese Academy of Medical Sciences, Beijing, China. 5Institute of Medical Biology, Chinese
Academy of Medical Sciences, Beijing, China. 6These authors contributed equally: Linlin Bao, Wei Deng, Baoying Huang, Hong Gao, Jiangning Liu. e-mail:;
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... As mouse ACE2 has a low affinity for S protein of SARS-CoV-2, different strategies were adopted to circumvent that mice are resistant to SARS-CoV-2 infection [34]. In a transgenic mouse expressing human ACE2 in the lungs, heart, kidneys and intestines (hACE2 mice), viral RNA was detected in the intestines of intranasally inoculated animals [35]. ...
... While SARS-CoV-2 replication in human enterocytes in vitro is supported by strong evidence, evidence of SARS-CoV-2 infection in the digestive tract of animals showed mixed results. In the intranasally inoculated hACE2 transgenic mice, viral RNA was detected, but no infectious virus was isolated and no viral antigens were detected in the intestines [35]. In another stable mouse model generated by CRISPR-Cas9 knock-in technology [36], robust virus replication were demonstrated in lungs. ...
... While in rhesus macaques infected via a combination of intranasal, intratracheal and ocular inoculation, viral RNA was and SARS-CoV-2 antigen were detected in the GI tract but not viral mRNA [42]. Thus viral RNA was detected in the intestines after virus inoculation (intranasal or intragastric) in almost all animal models [35,39,41,42,82] providing evidence for SARS-CoV-2 entry into enterocytes. However, evidence that the virus found in the GI tissues was infectious was observed only in rhesus monkeys in one study [41]. ...
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The gut has been proposed as a potential alternative entry route for SARS-CoV-2. This was mainly based on the high levels of SARS-CoV-2 receptor expressed in the gastrointestinal (GI) tract, the observations of GI disorders (such as diarrhea) in some COVID-19 patients and the detection of SARS-CoV-2 RNA in feces. However, the underlying mechanisms remain poorly understood. It has been proposed that SARS-CoV-2 can productively infect enterocytes, damaging the intestinal barrier and contributing to inflammatory response, which might lead to GI manifestations, including diarrhea. Here, we report a methodological approach to assess the evidence supporting the sequence of events driving SARS-CoV-2 enteric infection up to gut adverse outcomes. Exploring evidence permits to highlight knowledge gaps and current inconsistencies in the literature and to guide further research. Based on the current insights on SARS-CoV-2 intestinal infection and transmission, we then discuss the potential implication on clinical practice, including on long COVID. A better understanding of the GI implication in COVID-19 is still needed to improve disease management and could help identify innovative therapies or preventive actions targeting the GI tract.
... Human brain infection has now been demonstrated [35], although fulminant lethal brain infection is not a feature of COVID-19 [36,37]. A second mouse model of SARS-CoV-2 infection and COVID-19 disease involves expression (also as a transgene) of hACE2 driven by the mouse ACE2 (mACE2) promoter [38,39], which we independently generate herein and refer to as mACE2-hACE2 mice. This mouse model of COVID-19 is generally less severe, with infections usually self-limiting and non-lethal [38,39]. ...
... A second mouse model of SARS-CoV-2 infection and COVID-19 disease involves expression (also as a transgene) of hACE2 driven by the mouse ACE2 (mACE2) promoter [38,39], which we independently generate herein and refer to as mACE2-hACE2 mice. This mouse model of COVID-19 is generally less severe, with infections usually self-limiting and non-lethal [38,39]. A third model used a mouse-adapted strain of an original SARS-CoV-2 isolate, MA1, which is able to utilize mACE2 and is able to infect wild-type mice efficiently [32]. ...
... Differences between K18-hACE2 6J and K18-hACE2 6J/6N mice for any tissue were not significance. of transgenic mice where expression of hACE2 is driven by the mACE2 promoter (mACE2-hACE2 mice) [38]. We independently generated this mouse model (S8A and S8B Fig) and show that lung titers in mACE2-hACE2 mice were lower than those seen in K18-hACE2 mice on day 2 post infection (�2 logs) (Fig 6A). ...
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How well mouse models recapitulate the transcriptional profiles seen in humans remains debatable, with both conservation and diversity identified in various settings. Herein we use RNA-Seq data and bioinformatics approaches to analyze the transcriptional responses in SARS-CoV-2 infected lungs, comparing 4 human studies with the widely used K18-hACE2 mouse model, a model where hACE2 is expressed from the mouse ACE2 promoter, and a model that uses a mouse adapted virus and wild-type mice. Overlap of single copy orthologue differentially expressed genes (scoDEGs) between human and mouse studies was generally poor (≈15–35%). Rather than being associated with batch, sample treatment, viral load, lung damage or mouse model, the poor overlaps were primarily due to scoDEG expression differences between species. Importantly, analyses of immune signatures and inflammatory pathways illustrated highly significant concordances between species. As immunity and immunopathology are the focus of most studies, these mouse models can thus be viewed as representative and relevant models of COVID-19.
... Neutralization of the Delta variant authentic virus was greatly abrogated (Fig. 1c). In a human ACE2 transgenic mouse model 6 , intraperitoneal administrations of R1-32 at 4 mg kg −1 and 20 mg kg −1 at 1 h post intranasal inoculation of 5 × 10 5 plaque-forming units (p.f.u.) SARS-CoV-2 wild-type virus were able to significantly reduce viral load in lung, 3 d post infection, compared with the control group (Fig. 1d) spike and R1-32 epitope. a, Cryo-EM densities (low-pass filtered to 10 Å) of S-GSAS/6P spikes bound to R1-32 Fab and ACE2 at different stoichiometries. ...
... In vivo protection efficacy of the R1-32 antibody was evaluated using a hACE2 transgenic mouse model 6 . The animal study protocol was approved by the Ethics Committee of Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences (IACUC: 2020025). ...
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Population antibody response is thought to be important in selection of virus variants. We report that SARS-CoV-2 infection elicits a population immune response that is mediated by a lineage of VH1-69 germline antibodies. A representative antibody R1-32 from this lineage was isolated. By cryo-EM, we show that it targets a semi-cryptic epitope in the spike receptor-binding domain. Binding to this non-ACE2 competing epitope results in spike destruction, thereby inhibiting virus entry. On the basis of epitope location, neutralization mechanism and analysis of antibody binding to spike variants, we propose that recurrent substitutions at 452 and 490 are associated with immune evasion of the identified population antibody response. These substitutions, including L452R (present in the Delta variant), disrupt interactions mediated by the VH1-69-specific hydrophobic HCDR2 to impair antibody-antigen association, enabling variants to escape. The first Omicron variants were sensitive to antibody R1-32 but subvariants that harbour L452R quickly emerged and spread. Our results provide insights into how SARS-CoV-2 variants emerge and evade host immune responses. Amino acid changes in a newly identified spike epitope enabled the Delta variant to evade a population antibody response.
... As a result, the ACE and ACE2 are considered as opposing forces in the equation that determines the risk of hypertension and cardiovascular disease. ACE2 activates a defensive response in the lungs, lowering edema, permeability, and pulmonary injury (46),(47). Lower ACE2 levels should be harmful for patients with lung disease, so the frequency seen in COVID-19 patients could be a compromise between the negative association with viral infection (lower expression in the airway epithelia) and the positive association with respiratory and cardiovascular disease (lower expression in lung and other organs). The spike protein is an important predictor of the virus's tissue tropism and host range. ...
... Shared policy formulation and dissemination facilitate implementation by faculty to attain the institutional goals with excellence (Hazelkorn E, 2013;Peter Sn et al., 2020;Huo X et al., 2018). Written policies save much institutional prime time, preventing legal confusion, role conflict, and other chaotic operations because they indicate universities' best practices and enable institutional process reuse (Bao L et al., 2020). Besides impacting ethical conduct, the policy ensures guidance, consistency, accountability, clarify, and efficiency. ...
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Aim: This study investigated the intentions, opportunities, and barriers to engaging in a meaningful internationalization of higher education in Malawi, once a global player, to reposition itself on the global stage. Methods: This cross-sectional research was done between June and October 2021. Using a stratified sampling technique, we recruited 202 respondents from various higher education institutions in Malawi. Multi linear regression analysis was used to analyse the factors with the P-value set at 0.05 level of statistical significance. Results: The results indicated that most respondents were males (63.7%) who fell into 30 years age bracket. Further, the results from the multi linear regression analysis indicate that Institutional collaboration (ß=0.326, p=0.000, CI=0.27- 0.383), clear Policy on Mobility (ß=0.146, p=0.0.004, CI=0.047-0.246), experience (ß=0.083, p=0.117, CI=-0.021-0.186), academic rank (ß=0.114, p=0.000, CI=0.069-0.159) were positively statistically significant variables, whereas on the other hand, Occupation (ß=-0.131, p=0.002, CI=-0.213-0.49), academic qualification (ß=-0.106, p=0.013, CI=-0.19-0.023 and mobility Importance (ß=- 0.116, p=0.022, CI=-0.215-0.017) were negatively significant variables respectively. Conclusion and Recommendations: institutions need to invest in international and inter-institutional collaboration, clarify policy direction regarding academic mobility, keep track and linkages with mobile faculty, create a conducive social and formal institutional culture that attracts back mobile faculty, and reduce staff turnover. The study awakes African higher education systems to their former glory to align themselves with Sustainable Development Goals (2030) alongside Agenda 2063.
... In this pathway, the angiotensin-converting enzyme (ACE or ACE1) converts angiotensin-1 (Ang-1) to Ang-2; on the other hand, ACE2 converts Ang-2 to Ang-(1-7) [6]. Through binding to AT1 receptor, Ang-2 induces thrombosis, inflammation, fibrosis, and vasoconstriction, while Ang-(1-7) binds to AT2 receptor and hinders the reactions involved in fibrosis, thrombosis, and inflammation [7,8]. Interaction between ACE1/ACE2 predicts the risk of disorders such as hypertension, cardiovascular disease (CVD), and pulmonary diseases, hence, the ACE1/ACE2 axis influences the risk factors involved in COVID-19, and also plays a key role in susceptibility to severe clinical outcomes [9][10][11]. ...
Background Recent studies emphasize the significant impact of the renin-angiotensin aldosterone system (RAAS) as a risk factor associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. However, according to the literature, the effect of rs4646994 and rs2285666 polymorphisms on susceptibility and progression to severe clinical outcomes is still controversial. Our aim was to investigate the effect of polymorphisms such as rs4646994 and rs2285666 on susceptibility to coronavirus disease-2019 (COVID-19). Methods We conducted a comprehensive literature search using databases such as ISI Web of Science, PubMed, Scopus, and Google Scholar to retrieve studies on the effect of two polymorphisms (rs4646994 and rs2285666) of the angiotensin-converting enzyme (ACE) gene on COVID-19. Finally, the effect of each polymorphism on SARS-CoV-2 infection was measured based on the odds ratio with 95% confidence intervals. Results Analysis of the rs4646994 polymorphism showed that the frequency of the D allele in patients infected with COVID-19 was higher than that the I allele. Moreover, the authors found that the DD genotype increased the risk of severe disease by 1.7-fold in Asian population, whereas, this was not the case in the Western population. However, the rs4646994 II genotype plays a protective role against COVID-19 in Western countries. In the case of the rs2285666 polymorphism based on patient ethnicity, the C allele had the highest frequency. Interestingly, in people harboring the GG and TT genotypes, the risk of progression to severe disease significantly increased, while people with genotypes such as GA, AA and CC seem to be more resistant to severe Covid-19. Conclusions Based on geographical region, the rs4646994 DD genotype may be considered as a predictive biomarker to identify the susceptibility of human to SARS-CoV-2 infection and severe COVID-19 outcomes. We also concluded that individuals with GG and TT genotypes are significantly more susceptible to severe outcomes of disease, while conversely, individuals with GA, AA, and CC genotypes are less susceptible to severe COVID-19.
Creating a biomimetic in vitro lung model to recapitulate the infection and inflammatory reactions has been an important but challenging task for biomedical researchers. The 2D based cell culture models – culturing of lung epithelium – have long existed but lack multiple key physiological conditions, such as the involvement of different types of immune cells and the creation of connected lung models to study viral or bacterial infection between different individuals. Pioneers in organ-on-a-chip research have developed lung alveoli-on-a-chip and connected two lung chips with direct tubing and flow. Although this model provides a powerful tool for lung alveolar disease modeling, it still lacks interactions among immune cells, such as macrophages and monocytes, and the mimic of air flow and aerosol transmission between lung-chips is missing. Here, we report the development of an improved human lung physiological system (Lung-MPS) with both alveolar and pulmonary bronchial chambers that permits the integration of multiple immune cells into the system. We observed amplified inflammatory signals through the dynamic interactions among macrophages, epithelium, endothelium, and circulating monocytes. Furthermore, an integrated microdroplet/aerosol transmission system was fabricated and employed to study the propagation of pseudovirus particles containing microdroplets in integrated Lung-MPSs. Finally, a deep-learning algorithm was developed to characterize the activation of cells in this Lung-MPS. This Lung-MPS could provide an improved and more biomimetic sensory system for the study of COVID-19 and other high-risk infectious lung diseases.
Dünya çapında insanların önemli bir kısmının SARS-CoV-2 ile enfekte olmaları ve semptomlar görülmeden önce enfeksiyonu bilinmeyen şekilde yayabilmelerinden dolayı insanların yaban hayvanlarına COVID-19’u yayma riskleri bulunmaktadır. COVID-19’a yaban hayvanlarının duyarlılığının değerlendirildiği çalışmada primatlar, takiben karnivorlar, memeli deniz hayvanları, yabani kemirgenlerin yüksek potansiyel gösterdiği, laboratuvar kemirgenlerinin düşük riskte olduğu, kuşlar, reptiller ve amfibilerin de düşük riskte olduğu bildirildi. Kaplan, aslan, puma ve kar leoparına insanlardan COVID-19’un bulaştırıldığı bildirildi. COVID-19’la enfekte vizonların etkenleri insanlara ve kedilere bulaştırdığı gösterildi. COVID-19’un yabani gelincik ve vizonlara bulaşması halinde hayvanlar daha sonra devamlı rezervuar konaklar haline gelebilir ve insanlara ve diğer hayvan türlerine enfeksiyonu bulaştırabilir. Yaban hayvanları insanlarla yakın temastadır. Dolayısıyla COVID-19’a bağlı bulaşma olup olmadığının bilinmesi önemlidir. Bu çalışma kapsamında son yıllara ait çok sayıda bilimsel kaynak incelenerek insanlardan yaban hayvanlarına, yaban hayvanlarından tekrar insan ya da diğer hayvanlara COVID-19’un bulaştırılıp bulaştırılmadığı konularında ayrıntılı bilgiler verildi. Ayrıca insanlardan yaban hayvanlarına COVID-19’un bulaşmasının engellenmesine yönelik yapılması gereken uygulamalar hakkında bilgiler sunuldu.
Recently the prevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has become a pervasive threat to generic health. The SARS-CoV-2 spike (S) glycoprotein plays a fundamental role in binds and fusion to the angiotensin-converting enzyme 2 (ACE2). The multi-epitope peptide vaccines would be able to elicit both long-lasting humoral and cellular immune responses, resulting the eliminating SARS-CoV-2 infections as asymptomatic patients are in large numbers. Recently, the omicron variant of the SARS-CoV-2 became a variant of concern that contained just 15-point mutations in the receptor-binding domain of the spike protein. In order to eliminate new evidence on coronavirus variants of concern detected through epidemic intelligence, the conserved epitopes of the receptor-binding domain (RBD) and spike cleavage site is the most probable target for vaccine development to inducing binds and fusion inhibitors neutralizing antibodies respectively. In this study, we utilized bioinformatics tools for identifying and analyzing the spike (S) glycoprotein sequence, e.g. the prediction of the potential linear B-cell epitopes, B-cell multi‑epitope design, secondary and tertiary structures, physicochemical properties, solubility, antigenicity, allergenicity, the molecular docking and molecular dynamics simulation for the promising vaccine candidate against all variant of concern of SARS-CoV-2. Among the epitopes of the RBD region are surface-exposed epitopes SVYAWNRKRISNCV and ATRFASVYAWNRKR as the conserved sequences in all variants of concern can be a good candidate to induce an immune response. Communicated by Ramaswamy H. Sarma
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The adaptive immune response induced by SARS-CoV-2 plays a key role in the antiviral process and can protect the body from the threat of infection for a certain period of time. However, owing to the limitations of clinical studies, the antiviral mechanisms, protective thresholds, and persistence of the immune memory of adaptive immune responses remain unclear. This review summarizes existing research models for SARS-CoV-2 and elaborates on the advantages of animal models in simulating the clinical symptoms of COVID-19 in humans. In addition, we systematically summarize the research progress on the SARS-CoV-2 adaptive immune response and the remaining key issues, as well as the application and prospects of animal models in this field. This paper provides direction for in-depth analysis of the anti-SARS-CoV-2 mechanism of the adaptive immune response and lays the foundation for the development and application of vaccines and drugs.
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Background: Human infections with zoonotic coronaviruses (CoVs), including severe acute respiratory syndrome (SARS)-CoV and Middle East respiratory syndrome (MERS)-CoV, have raised great public health concern globally. Here, we report a novel bat-origin CoV causing severe and fatal pneumonia in humans. Methods: We collected clinical data and bronchoalveolar lavage (BAL) specimens from five patients with severe pneumonia from Jin Yin-tan Hospital of Wuhan, Hubei province, China. Nucleic acids of the BAL were extracted and subjected to next-generation sequencing. Virus isolation was carried out, and maximum-likelihood phylogenetic trees were constructed. Results: Five patients hospitalized from December 18 to December 29, 2019 presented with fever, cough, and dyspnea accompanied by complications of acute respiratory distress syndrome. Chest radiography revealed diffuse opacities and consolidation. One of these patients died. Sequence results revealed the presence of a previously unknown β-CoV strain in all five patients, with 99.8-99.9% nucleotide identities among the isolates. These isolates showed 79.0% nucleotide identity with the sequence of SARS-CoV (GenBank NC_004718) and 51.8% identity with the sequence of MERS-CoV (GenBank NC_019843). The virus is phylogenetically closest to a bat SARS-like CoV (SL-ZC45, GenBank MG772933) with 87.6-87.7% nucleotide identity, but is in a separate clade. Moreover, these viruses have a single intact open reading frame gene 8, as a further indicator of bat-origin CoVs. However, the amino acid sequence of the tentative receptor-binding domain resembles that of SARS-CoV, indicating that these viruses might use the same receptor. Conclusion: A novel bat-borne CoV was identified that is associated with severe and fatal respiratory disease in humans.
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In December 2019, a cluster of patients with pneumonia of unknown cause was linked to a seafood wholesale market in Wuhan, China. A previously unknown betacoronavirus was discovered through the use of unbiased sequencing in samples from patients with pneumonia. Human airway epithelial cells were used to isolate a novel coronavirus, named 2019-nCoV, which formed another clade within the subgenus sarbecovirus, Orthocoronavirinae subfamily. Different from both MERS-CoV and SARS-CoV, 2019-nCoV is the seventh member of the family of coronaviruses that infect humans. Enhanced surveillance and further investigation are ongoing. (Funded by the National Key Research and Development Program of China and the National Major Project for Control and Prevention of Infectious Disease in China.).
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Background: An ongoing outbreak of pneumonia associated with a novel coronavirus was reported in Wuhan city, Hubei province, China. Affected patients were geographically linked with a local wet market as a potential source. No data on person-to-person or nosocomial transmission have been published to date. Methods: In this study, we report the epidemiological, clinical, laboratory, radiological, and microbiological findings of five patients in a family cluster who presented with unexplained pneumonia after returning to Shenzhen, Guangdong province, China, after a visit to Wuhan, and an additional family member who did not travel to Wuhan. Phylogenetic analysis of genetic sequences from these patients were done. Findings: From Jan 10, 2020, we enrolled a family of six patients who travelled to Wuhan from Shenzhen between Dec 29, 2019 and Jan 4, 2020. Of six family members who travelled to Wuhan, five were identified as infected with the novel coronavirus. Additionally, one family member, who did not travel to Wuhan, became infected with the virus after several days of contact with four of the family members. None of the family members had contacts with Wuhan markets or animals, although two had visited a Wuhan hospital. Five family members (aged 36-66 years) presented with fever, upper or lower respiratory tract symptoms, or diarrhoea, or a combination of these 3-6 days after exposure. They presented to our hospital (The University of Hong Kong-Shenzhen Hospital, Shenzhen) 6-10 days after symptom onset. They and one asymptomatic child (aged 10 years) had radiological ground-glass lung opacities. Older patients (aged >60 years) had more systemic symptoms, extensive radiological ground-glass lung changes, lymphopenia, thrombocytopenia, and increased C-reactive protein and lactate dehydrogenase levels. The nasopharyngeal or throat swabs of these six patients were negative for known respiratory microbes by point-of-care multiplex RT-PCR, but five patients (four adults and the child) were RT-PCR positive for genes encoding the internal RNA-dependent RNA polymerase and surface Spike protein of this novel coronavirus, which were confirmed by Sanger sequencing. Phylogenetic analysis of these five patients' RT-PCR amplicons and two full genomes by next-generation sequencing showed that this is a novel coronavirus, which is closest to the bat severe acute respiatory syndrome (SARS)-related coronaviruses found in Chinese horseshoe bats. Interpretation: Our findings are consistent with person-to-person transmission of this novel coronavirus in hospital and family settings, and the reports of infected travellers in other geographical regions. Funding: The Shaw Foundation Hong Kong, Michael Seak-Kan Tong, Respiratory Viral Research Foundation Limited, Hui Ming, Hui Hoy and Chow Sin Lan Charity Fund Limited, Marina Man-Wai Lee, the Hong Kong Hainan Commercial Association South China Microbiology Research Fund, Sanming Project of Medicine (Shenzhen), and High Level-Hospital Program (Guangdong Health Commission).
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Background: A recent cluster of pneumonia cases in Wuhan, China, was caused by a novel betacoronavirus, the 2019 novel coronavirus (2019-nCoV). We report the epidemiological, clinical, laboratory, and radiological characteristics and treatment and clinical outcomes of these patients. Methods: All patients with suspected 2019-nCoV were admitted to a designated hospital in Wuhan. We prospectively collected and analysed data on patients with laboratory-confirmed 2019-nCoV infection by real-time RT-PCR and next-generation sequencing. Data were obtained with standardised data collection forms shared by the International Severe Acute Respiratory and Emerging Infection Consortium from electronic medical records. Researchers also directly communicated with patients or their families to ascertain epidemiological and symptom data. Outcomes were also compared between patients who had been admitted to the intensive care unit (ICU) and those who had not. Findings: By Jan 2, 2020, 41 admitted hospital patients had been identified as having laboratory-confirmed 2019-nCoV infection. Most of the infected patients were men (30 [73%] of 41); less than half had underlying diseases (13 [32%]), including diabetes (eight [20%]), hypertension (six [15%]), and cardiovascular disease (six [15%]). Median age was 49·0 years (IQR 41·0-58·0). 27 (66%) of 41 patients had been exposed to Huanan seafood market. One family cluster was found. Common symptoms at onset of illness were fever (40 [98%] of 41 patients), cough (31 [76%]), and myalgia or fatigue (18 [44%]); less common symptoms were sputum production (11 [28%] of 39), headache (three [8%] of 38), haemoptysis (two [5%] of 39), and diarrhoea (one [3%] of 38). Dyspnoea developed in 22 (55%) of 40 patients (median time from illness onset to dyspnoea 8·0 days [IQR 5·0-13·0]). 26 (63%) of 41 patients had lymphopenia. All 41 patients had pneumonia with abnormal findings on chest CT. Complications included acute respiratory distress syndrome (12 [29%]), RNAaemia (six [15%]), acute cardiac injury (five [12%]) and secondary infection (four [10%]). 13 (32%) patients were admitted to an ICU and six (15%) died. Compared with non-ICU patients, ICU patients had higher plasma levels of IL2, IL7, IL10, GSCF, IP10, MCP1, MIP1A, and TNFα. Interpretation: The 2019-nCoV infection caused clusters of severe respiratory illness similar to severe acute respiratory syndrome coronavirus and was associated with ICU admission and high mortality. Major gaps in our knowledge of the origin, epidemiology, duration of human transmission, and clinical spectrum of disease need fulfilment by future studies. Funding: Ministry of Science and Technology, Chinese Academy of Medical Sciences, National Natural Science Foundation of China, and Beijing Municipal Science and Technology Commission.
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During several months of 2003, a newly identified illness termed severe acute respiratory syndrome (SARS) spread rapidly through the world. A new coronavirus (SARS-CoV) was identified as the SARS pathogen, which triggered severe pneumonia and acute, often lethal, lung failure. Moreover, among infected individuals influenza such as the Spanish flu and the emergence of new respiratory disease viruses have caused high lethality resulting from acute lung failure. In cell lines, angiotensin-converting enzyme 2 (ACE2) has been identified as a potential SARS-CoV receptor. The high lethality of SARS-CoV infections, its enormous economic and social impact, fears of renewed outbreaks as well as the potential misuse of such viruses as biologic weapons make it paramount to understand the pathogenesis of SARS-CoV. Here we provide the first genetic proof that ACE2 is a crucial SARS-CoV receptor in vivo. SARS-CoV infections and the Spike protein of the SARS-CoV reduce ACE2 expression. Notably, injection of SARS-CoV Spike into mice worsens acute lung failure in vivo that can be attenuated by blocking the renin-angiotensin pathway. These results provide a molecular explanation why SARS-CoV infections cause severe and often lethal lung failure and suggest a rational therapy for SARS and possibly other respiratory disease viruses.
The emergence of Middle East respiratory syndrome coronavirus (MERS-CoV) in 2012 marked the second introduction of a highly pathogenic coronavirus into the human population in the twenty-first century. The continuing introductions of MERS-CoV from dromedary camels, the subsequent travel-related viral spread, the unprecedented nosocomial outbreaks and the high case-fatality rates highlight the need for prophylactic and therapeutic measures. Scientific advancements since the 2002-2003 severe acute respiratory syndrome coronavirus (SARS-CoV) pandemic allowed for rapid progress in our understanding of the epidemiology and pathogenesis of MERS-CoV and the development of therapeutics. In this Review, we detail our present understanding of the transmission and pathogenesis of SARS-CoV and MERS-CoV, and discuss the current state of development of measures to combat emerging coronaviruses.
To establish a small animal model of severe acute respiratory syndrome (SARS), we developed a mouse model of human severe acute respiratory syndrome coronavirus (SARS-CoV) infection by introducing the human gene for angiotensin-converting enzyme 2 (hACE2) (the cellular receptor of SARS-CoV), driven by the mouse ACE2 promoter, into the mouse genome. The hACE2 gene was expressed in lung, heart, kidney, and intestine. We also evaluated the responses of wild-type and transgenic mice to SARS-CoV inoculation. At days 3 and 7 postinoculation, SARS-CoV replicated more efficiently in the lungs of transgenic mice than in those of wild-type mice. In addition, transgenic mice had more severe pulmonary lesions, including interstitial hyperemia and hemorrhage, monocytic and lymphocytic infiltration, protein exudation, and alveolar epithelial cell proliferation and desquamation. Other pathologic changes, including vasculitis, degeneration, and necrosis, were found in the extrapulmonary organs of transgenic mice, and viral antigen was found in brain. Therefore, transgenic mice were more susceptible to SARS-CoV than were wild-type mice, and susceptibility was associated with severe pathologic changes that resembled human SARS infection. These mice will be valuable for testing potential vaccine and antiviral drug therapies and for furthering our understanding of SARS pathogenesis.
Infection of humans with the severe acute respiratory syndrome coronavirus (SARS-CoV) results in substantial morbidity and mortality, with death resulting primarily from respiratory failure. While the lungs are the major site of infection, the brain is also infected in some patients. Brain infection may result in long-term neurological sequelae, but little is known about the pathogenesis of SARS-CoV in this organ. We previously showed that the brain was a major target organ for infection in mice that are transgenic for the SARS-CoV receptor (human angiotensin-converting enzyme 2). Herein, we use these mice to show that virus enters the brain primarily via the olfactory bulb, and infection results in rapid, transneuronal spread to connected areas of the brain. This extensive neuronal infection is the main cause of death because intracranial inoculation with low doses of virus results in a uniformly lethal disease even though little infection is detected in the lungs. Death of the animal likely results from dysfunction and/or death of infected neurons, especially those located in cardiorespiratory centers in the medulla. Remarkably, the virus induces minimal cellular infiltration in the brain. Our results show that neurons are a highly susceptible target for SARS-CoV and that only the absence of the host cell receptor prevents severe murine brain disease.