ABSTRACT
In cultured cells, SARS-CoV-2 infects cells via multiple pathways using different host proteases. Recent studies have shown that the furin and TMPRSS2 (furin/TMPRSS2)-dependent pathway plays a minor role in infection of the Omicron variant. Here, we confirm that Omicron uses the furin/TMPRSS2-dependent pathway inefficiently and enters cells mainly using the cathepsin-dependent endocytosis pathway in TMPRSS2-expressing VeroE6/TMPRSS2 and Calu-3 cells. This is the case despite efficient cleavage of the spike protein of Omicron. However, in the airways of TMPRSS2-knockout mice, Omicron infection is significantly reduced. We furthermore show that propagation of the mouse-adapted SARS-CoV-2 QHmusX strain and human clinical isolates of Beta and Gamma is reduced in TMPRSS2-knockout mice. Therefore, the Omicron variant isn't an exception in using TMPRSS2 in vivo, and analysis with TMPRSS2-knockout mice is important when evaluating SARS-CoV-2 variants. In conclusion, this study shows that TMPRSS2 is critically important for SARS-CoV-2 infection of murine airways, including the Omicron variant.
Subject(s)
COVID-19 , SARS-CoV-2 , Animals , Humans , Mice , Cathepsins , Furin/genetics , Furin/metabolism , Mice, Knockout , Peptide Hydrolases , Serine Endopeptidases/genetics , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/metabolism , Virus InternalizationABSTRACT
The Diamond Princess cruise ship was put under quarantine offshore Yokohama, Japan, after a passenger who disembarked in Hong Kong was confirmed as a coronavirus disease 2019 case. We performed whole-genome sequencing of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) directly from PCR+ clinical specimens and conducted a phylogenetic analysis of the outbreak. All tested isolates exhibited a transversion at G11083T, suggesting that SARS-CoV-2 dissemination on the Diamond Princess originated from a single introduction event before the quarantine started. Although further spreading might have been prevented by quarantine, some progeny clusters could be linked to transmission through mass-gathering events in the recreational areas and direct transmission among passengers who shared cabins during the quarantine. This study demonstrates the usefulness of haplotype network/phylogeny analysis in identifying potential infection routes.
Subject(s)
Betacoronavirus/genetics , Coronavirus Infections/virology , Genome, Viral , Haplotypes , Phylogeny , Pneumonia, Viral/virology , Ships , Betacoronavirus/classification , Betacoronavirus/isolation & purification , COVID-19 , Coronavirus Infections/prevention & control , Coronavirus Infections/transmission , Humans , Pandemics/prevention & control , Pneumonia, Viral/prevention & control , Pneumonia, Viral/transmission , Quarantine , SARS-CoV-2 , Whole Genome SequencingABSTRACT
During the emergence of novel coronavirus 2019 (nCoV) outbreak in Wuhan city, China at the end of 2019, there was movement of many airline travelers between Wuhan and Japan, suggesting that the Japanese population was at high risk of infection by the virus. Hence, we urgently developed diagnostic systems for detection of 2019 nCoV. Two nested RT-PCR and two real-time RT-PCR assays were adapted for use in Japan. As of February 8, 2020, these assays have successfully detected 25 positive cases of infection in Japan.
Subject(s)
Betacoronavirus/genetics , Clinical Laboratory Techniques/methods , Coronavirus Infections/diagnosis , Pneumonia, Viral/diagnosis , RNA, Viral/analysis , COVID-19 , COVID-19 Testing , COVID-19 Vaccines , Humans , Japan , Pandemics , Polyproteins , Reverse Transcriptase Polymerase Chain Reaction/methods , SARS-CoV-2 , Spike Glycoprotein, Coronavirus/genetics , Viral Proteins/geneticsABSTRACT
During a COVID-19 outbreak on the Diamond Princess cruise ship we sampled environmental surfaces after passengers and crew vacated cabins. SARS-CoV-2 RNA was detected in 58 of 601 samples (10%) from case cabins 1-17 days after cabins were vacated but not from noncase cabins. There was no difference in detection proportion between cabins of symptomatic (15%, 28/189; cycle quantification [Cq], 29.79-38.86) and asymptomatic cases (21%, 28/131; Cq, 26.21-38.99). No SARS-CoV-2 virus was isolated from any of the samples. Transmission risk of SARS-CoV-2 from symptomatic and asymptomatic patients may be similar and surfaces could be involved in transmission.
Subject(s)
Betacoronavirus/isolation & purification , Coronavirus Infections/epidemiology , Disease Outbreaks , Environmental Monitoring , Pneumonia, Viral/epidemiology , RNA, Viral/isolation & purification , Betacoronavirus/genetics , COVID-19 , Coronavirus Infections/transmission , Coronavirus Infections/virology , Humans , Pandemics , Pneumonia, Viral/transmission , Pneumonia, Viral/virology , SARS-CoV-2 , Sampling Studies , Ships , Specimen HandlingABSTRACT
In early 2020, Japan repatriated 566 nationals from China. Universal laboratory testing and 14-day monitoring of returnees detected 12 cases of severe acute respiratory syndrome coronavirus 2 infection; initial screening results were negative for 5. Common outcomes were remaining asymptomatic (n = 4) and pneumonia (n = 6). Overall, screening performed poorly.
Subject(s)
Betacoronavirus , Coronavirus Infections/epidemiology , Pneumonia, Viral/epidemiology , Adult , Aged , COVID-19 , China , Female , Humans , Japan/epidemiology , Male , Middle Aged , Pandemics , Polymerase Chain Reaction , SARS-CoV-2 , TravelABSTRACT
A novel betacoronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which caused a large respiratory outbreak in Wuhan, China in December 2019, is currently spreading across many countries globally. Here, we show that a TMPRSS2-expressing VeroE6 cell line is highly susceptible to SARS-CoV-2 infection, making it useful for isolating and propagating SARS-CoV-2. Our results reveal that, in common with SARS- and Middle East respiratory syndrome-CoV, SARS-CoV-2 infection is enhanced by TMPRSS2.