Your browser doesn't support javascript.
Show: 20 | 50 | 100
Results 1 - 10 de 10
Filter
1.
J Appl Lab Med ; 2021 Feb 25.
Article in English | MEDLINE | ID: covidwho-1101853

ABSTRACT

BACKGROUND: Widespread testing of SARS-CoV-2 has resulted in shortages of collection devices and transport media. We evaluated the stability of flocked swabs inoculated with SARS-CoV-2-containing specimen incubated dry (i.e. without transport medium) at room temperature. METHODS: A pool of SARS-CoV-2 positive specimen was used to inoculate flocked swabs. Five swabs were placed immediately into UTM following inoculation, and tested immediately (day 0). Fifteen of the swabs were placed into sterile 15 mL conical tubes and incubated at room temperature for one, two, or seven days. Following incubation, swabs were hydrated in separate vials of UTM and tested. This protocol was repeated for viral transport media (VTM) and saline. As a comparison, a series of swabs was prepared and tested in parallel, but stored in the corresponding liquid transport media (UTM, VTM, or saline) and incubated at room temperature. Testing was performed at 1, 2, and 7 days post inoculation in duplicate. All molecular testing was performed using the Roche cobas SARS-CoV-2 assay. RESULTS: All dry swabs tested at days 1, 2, and 7 provided results that were within two cycle thresholds (Cts) of the average Ct values for swabs hydrated in the same media and tested on day 0. There was no statistical difference in Ct values between swabs incubated in liquid media versus dry swabs incubated at room temperature prior to hydration in liquid media. CONCLUSIONS: The utilization of "dry swabs" may simplify specimen collection, negate the need for liquid transport media, and mitigate safety risks while preserving the accuracy of testing.

3.
Nat Immunol ; 21(11): 1327-1335, 2020 11.
Article in English | MEDLINE | ID: covidwho-728991

ABSTRACT

Although animal models have been evaluated for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, none have fully recapitulated the lung disease phenotypes seen in humans who have been hospitalized. Here, we evaluate transgenic mice expressing the human angiotensin I-converting enzyme 2 (ACE2) receptor driven by the cytokeratin-18 (K18) gene promoter (K18-hACE2) as a model of SARS-CoV-2 infection. Intranasal inoculation of SARS-CoV-2 in K18-hACE2 mice results in high levels of viral infection in lungs, with spread to other organs. A decline in pulmonary function occurs 4 days after peak viral titer and correlates with infiltration of monocytes, neutrophils and activated T cells. SARS-CoV-2-infected lung tissues show a massively upregulated innate immune response with signatures of nuclear factor-κB-dependent, type I and II interferon signaling, and leukocyte activation pathways. Thus, the K18-hACE2 model of SARS-CoV-2 infection shares many features of severe COVID-19 infection and can be used to define the basis of lung disease and test immune and antiviral-based countermeasures.


Subject(s)
Betacoronavirus/immunology , Coronavirus Infections/pathology , Immunity, Innate/immunology , Peptidyl-Dipeptidase A/genetics , Pneumonia, Viral/pathology , Pneumonia/pathology , Animals , Chlorocebus aethiops , Coronavirus Infections/immunology , Disease Models, Animal , Female , Humans , Interferon Type I/immunology , Interferon-gamma/immunology , Keratin-18/genetics , Leukocytes/immunology , Lymphocyte Activation/immunology , Male , Mice , Mice, Transgenic , Monocytes/immunology , NF-kappa B/immunology , Neutrophil Infiltration/immunology , Neutrophils/immunology , Pandemics , Pneumonia/genetics , Pneumonia/virology , Pneumonia, Viral/immunology , Promoter Regions, Genetic/genetics , T-Lymphocytes/immunology , Vero Cells , Virus Replication/immunology
4.
Cell ; 183(1): 169-184.e13, 2020 10 01.
Article in English | MEDLINE | ID: covidwho-720448

ABSTRACT

The coronavirus disease 2019 pandemic has made deployment of an effective vaccine a global health priority. We evaluated the protective activity of a chimpanzee adenovirus-vectored vaccine encoding a prefusion stabilized spike protein (ChAd-SARS-CoV-2-S) in challenge studies with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and mice expressing the human angiotensin-converting enzyme 2 receptor. Intramuscular dosing of ChAd-SARS-CoV-2-S induces robust systemic humoral and cell-mediated immune responses and protects against lung infection, inflammation, and pathology but does not confer sterilizing immunity, as evidenced by detection of viral RNA and induction of anti-nucleoprotein antibodies after SARS-CoV-2 challenge. In contrast, a single intranasal dose of ChAd-SARS-CoV-2-S induces high levels of neutralizing antibodies, promotes systemic and mucosal immunoglobulin A (IgA) and T cell responses, and almost entirely prevents SARS-CoV-2 infection in both the upper and lower respiratory tracts. Intranasal administration of ChAd-SARS-CoV-2-S is a candidate for preventing SARS-CoV-2 infection and transmission and curtailing pandemic spread.


Subject(s)
Coronavirus Infections/immunology , Immunogenicity, Vaccine , Pneumonia, Viral/immunology , Viral Vaccines/immunology , Adenoviridae/genetics , Administration, Intranasal , Animals , Antibodies, Neutralizing/blood , Antibodies, Viral/blood , Chlorocebus aethiops , Coronavirus Infections/pathology , Coronavirus Infections/prevention & control , Female , HEK293 Cells , Humans , Injections, Intramuscular , Mice , Mice, Inbred BALB C , Pandemics , Pneumonia, Viral/pathology , Respiratory Mucosa/immunology , Respiratory Mucosa/pathology , Respiratory Mucosa/virology , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/immunology , Vero Cells , Viral Vaccines/administration & dosage
5.
Cell Host Microbe ; 28(3): 465-474.e4, 2020 09 09.
Article in English | MEDLINE | ID: covidwho-710174

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused millions of human infections, and an effective vaccine is critical to mitigate coronavirus-induced disease 2019 (COVID-19). Previously, we developed a replication-competent vesicular stomatitis virus (VSV) expressing a modified form of the SARS-CoV-2 spike gene in place of the native glycoprotein gene (VSV-eGFP-SARS-CoV-2). Here, we show that vaccination with VSV-eGFP-SARS-CoV-2 generates neutralizing immune responses and protects mice from SARS-CoV-2. Immunization of mice with VSV-eGFP-SARS-CoV-2 elicits high antibody titers that neutralize SARS-CoV-2 and target the receptor binding domain that engages human angiotensin-converting enzyme-2 (ACE2). Upon challenge with a human isolate of SARS-CoV-2, mice that expressed human ACE2 and were immunized with VSV-eGFP-SARS-CoV-2 show profoundly reduced viral infection and inflammation in the lung, indicating protection against pneumonia. Passive transfer of sera from VSV-eGFP-SARS-CoV-2-immunized animals also protects naive mice from SARS-CoV-2 challenge. These data support development of VSV-SARS-CoV-2 as an attenuated, replication-competent vaccine against SARS-CoV-2.


Subject(s)
Betacoronavirus , Coronavirus Infections/prevention & control , Pandemics/prevention & control , Pneumonia, Viral/prevention & control , Vesicular stomatitis Indiana virus/genetics , Viral Vaccines/genetics , Animals , Antibodies, Neutralizing/blood , Antibodies, Viral/blood , Betacoronavirus/immunology , Betacoronavirus/pathogenicity , Chlorocebus aethiops , Coronavirus Infections/genetics , Coronavirus Infections/immunology , Coronavirus Infections/virology , Disease Models, Animal , Genetic Vectors , Green Fluorescent Proteins/genetics , Host Microbial Interactions/immunology , Humans , Lung/immunology , Lung/pathology , Lung/virology , Mice , Mice, Inbred BALB C , Mice, Transgenic , Peptidyl-Dipeptidase A/genetics , Pneumonia, Viral/immunology , Pneumonia, Viral/virology , Receptors, Virus/genetics , Translational Medical Research , Vaccines, Synthetic/genetics , Vaccines, Synthetic/immunology , Vaccines, Synthetic/pharmacology , Vero Cells , Vesicular stomatitis Indiana virus/immunology , Viral Vaccines/immunology , Viral Vaccines/pharmacology
6.
bioRxiv ; 2020 Jul 10.
Article in English | MEDLINE | ID: covidwho-665969

ABSTRACT

Severe Acute Respiratory Syndrome Coronavirus -2 (SARS-CoV-2) emerged in late 2019 and has spread worldwide resulting in the Coronavirus Disease 2019 (COVID-19) pandemic. Although animal models have been evaluated for SARS-CoV-2 infection, none have recapitulated the severe lung disease phenotypes seen in hospitalized human cases. Here, we evaluate heterozygous transgenic mice expressing the human ACE2 receptor driven by the epithelial cell cytokeratin-18 gene promoter (K18-hACE2) as a model of SARS-CoV-2 infection. Intranasal inoculation of SARS-CoV-2 in K18-hACE2 mice results in high levels of viral infection in lung tissues with additional spread to other organs. Remarkably, a decline in pulmonary function, as measured by static and dynamic tests of respiratory capacity, occurs 4 days after peak viral titer and correlates with an inflammatory response marked by infiltration into the lung of monocytes, neutrophils, and activated T cells resulting in pneumonia. Cytokine profiling and RNA sequencing analysis of SARS-CoV-2-infected lung tissues show a massively upregulated innate immune response with prominent signatures of NF-kB-dependent, type I and II interferon signaling, and leukocyte activation pathways. Thus, the K18-hACE2 model of SARS-CoV-2 infection recapitulates many features of severe COVID-19 infection in humans and can be used to define the mechanistic basis of lung disease and test immune and antiviral-based countermeasures.

7.
bioRxiv ; 2020 Jul 10.
Article in English | MEDLINE | ID: covidwho-663086

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused millions of human infections and hundreds of thousands of deaths. Accordingly, an effective vaccine is of critical importance in mitigating coronavirus induced disease 2019 (COVID-19) and curtailing the pandemic. We developed a replication-competent vesicular stomatitis virus (VSV)-based vaccine by introducing a modified form of the SARS-CoV-2 spike gene in place of the native glycoprotein gene (VSV-eGFP-SARS-CoV-2). Immunization of mice with VSV-eGFP-SARS-CoV-2 elicits high titers of antibodies that neutralize SARS-CoV-2 infection and target the receptor binding domain that engages human angiotensin converting enzyme-2 (ACE2). Upon challenge with a human isolate of SARS-CoV-2, mice expressing human ACE2 and immunized with VSV-eGFP-SARS-CoV-2 show profoundly reduced viral infection and inflammation in the lung indicating protection against pneumonia. Finally, passive transfer of sera from VSV-eGFP-SARS-CoV-2-immunized animals protects naïve mice from SARS-CoV-2 challenge. These data support development of VSV-eGFP-SARS-CoV-2 as an attenuated, replication-competent vaccine against SARS-CoV-2.

8.
Nature ; 584(7821): 443-449, 2020 08.
Article in English | MEDLINE | ID: covidwho-647154

ABSTRACT

The ongoing pandemic of coronavirus disease 2019 (COVID-19), which is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is a major threat to global health1 and the medical countermeasures available so far are limited2,3. Moreover, we currently lack a thorough understanding of the mechanisms of humoral immunity to SARS-CoV-24. Here we analyse a large panel of human monoclonal antibodies that target the spike (S) glycoprotein5, and identify several that exhibit potent neutralizing activity and fully block the receptor-binding domain of the S protein (SRBD) from interacting with human angiotensin-converting enzyme 2 (ACE2). Using competition-binding, structural and functional studies, we show that the monoclonal antibodies can be clustered into classes that recognize distinct epitopes on the SRBD, as well as distinct conformational states of the S trimer. Two potently neutralizing monoclonal antibodies, COV2-2196 and COV2-2130, which recognize non-overlapping sites, bound simultaneously to the S protein and neutralized wild-type SARS-CoV-2 virus in a synergistic manner. In two mouse models of SARS-CoV-2 infection, passive transfer of COV2-2196, COV2-2130 or a combination of both of these antibodies protected mice from weight loss and reduced the viral burden and levels of inflammation in the lungs. In addition, passive transfer of either of two of the most potent ACE2-blocking monoclonal antibodies (COV2-2196 or COV2-2381) as monotherapy protected rhesus macaques from SARS-CoV-2 infection. These results identify protective epitopes on the SRBD and provide a structure-based framework for rational vaccine design and the selection of robust immunotherapeutic agents.


Subject(s)
Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , Betacoronavirus/immunology , Coronavirus Infections/immunology , Coronavirus Infections/prevention & control , Pandemics/prevention & control , Pneumonia, Viral/immunology , Pneumonia, Viral/prevention & control , Animals , Antibodies, Monoclonal/immunology , Betacoronavirus/chemistry , Binding, Competitive , Cell Line , Cross Reactions , Disease Models, Animal , Epitopes, B-Lymphocyte/chemistry , Epitopes, B-Lymphocyte/immunology , Female , Humans , Macaca mulatta , Male , Mice , Middle Aged , Neutralization Tests , Peptidyl-Dipeptidase A/genetics , Peptidyl-Dipeptidase A/metabolism , Pre-Exposure Prophylaxis , SARS Virus/chemistry , SARS Virus/immunology , Severe Acute Respiratory Syndrome/immunology , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/immunology , Spike Glycoprotein, Coronavirus/metabolism
9.
Cell ; 182(3): 744-753.e4, 2020 08 06.
Article in English | MEDLINE | ID: covidwho-592074

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a pandemic with millions of human infections. One limitation to the evaluation of potential therapies and vaccines to inhibit SARS-CoV-2 infection and ameliorate disease is the lack of susceptible small animals in large numbers. Commercially available laboratory strains of mice are not readily infected by SARS-CoV-2 because of species-specific differences in their angiotensin-converting enzyme 2 (ACE2) receptors. Here, we transduced replication-defective adenoviruses encoding human ACE2 via intranasal administration into BALB/c mice and established receptor expression in lung tissues. hACE2-transduced mice were productively infected with SARS-CoV-2, and this resulted in high viral titers in the lung, lung pathology, and weight loss. Passive transfer of a neutralizing monoclonal antibody reduced viral burden in the lung and mitigated inflammation and weight loss. The development of an accessible mouse model of SARS-CoV-2 infection and pathogenesis will expedite the testing and deployment of therapeutics and vaccines.


Subject(s)
Antibodies, Monoclonal/therapeutic use , Antibodies, Neutralizing/therapeutic use , Antibodies, Viral/therapeutic use , Betacoronavirus/immunology , Coronavirus Infections/therapy , Disease Models, Animal , Pneumonia, Viral/therapy , Animals , Chlorocebus aethiops , Coronavirus Infections/virology , Female , HEK293 Cells , Humans , Immunization, Passive/methods , Lung/metabolism , Lung/virology , Male , Mice , Mice, Inbred BALB C , Mice, Inbred C57BL , Mice, Inbred DBA , Mice, Knockout , Pandemics , Peptidyl-Dipeptidase A/genetics , Peptidyl-Dipeptidase A/metabolism , Pneumonia, Viral/virology , Transduction, Genetic , Vero Cells , Viral Load/immunology
10.
Sci Immunol ; 5(47)2020 05 13.
Article in English | MEDLINE | ID: covidwho-260039

ABSTRACT

Gastrointestinal symptoms and fecal shedding of SARS-CoV-2 RNA are frequently observed in COVID-19 patients. However, it is unclear whether SARS-CoV-2 replicates in the human intestine and contributes to possible fecal-oral transmission. Here, we report productive infection of SARS-CoV-2 in ACE2+ mature enterocytes in human small intestinal enteroids. Expression of two mucosa-specific serine proteases, TMPRSS2 and TMPRSS4, facilitated SARS-CoV-2 spike fusogenic activity and promoted virus entry into host cells. We also demonstrate that viruses released into the intestinal lumen were inactivated by simulated human colonic fluid, and infectious virus was not recovered from the stool specimens of COVID-19 patients. Our results highlight the intestine as a potential site of SARS-CoV-2 replication, which may contribute to local and systemic illness and overall disease progression.


Subject(s)
Betacoronavirus/physiology , Enterocytes/virology , Membrane Proteins/metabolism , Serine Endopeptidases/metabolism , Virus Internalization , Animals , Cell Line , Duodenum/cytology , Enterocytes/pathology , Humans , Mice , Organoids/virology , Peptidyl-Dipeptidase A/metabolism , Rotavirus/physiology , Vesiculovirus/genetics
SELECTION OF CITATIONS
SEARCH DETAIL