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1.
Front Immunol ; 12: 708184, 2021.
Article in English | MEDLINE | ID: covidwho-1346403

ABSTRACT

There is a worldwide pandemic of Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection; yet our understanding remains limited on the characteristic of antibodies, especially for dynamic long-term tracking. Sequential serum samples were collected up to 416 days post onset of symptoms (POS) from 102 patients who were hospitalized with coronavirus disease 2019 (COVID-19). Immunoglobulin (Ig)G, IgM, and IgA levels targeting SARS-CoV-2 spike 1 receptor-binding domain (S1-RBD), spike 2 extracellular domain (S2-ECD), and nucleocapsid protein (N) were quantified as well as neutralizing activity. We were pleasantly surprised to find that the antibody remained detective and effective for more than a year POS. We also found the varied reactions of different antibodies as time passed: N-IgA rose most rapidly in the early stage of infection, while S2-IgG was present at a high level in the long time of observation. This study described the long traceable antibody response of the COVID-19 and offered hints about targets to screen for postinfectious immunity and for vaccination development of SARS-CoV-2.


Subject(s)
Antibodies, Neutralizing/blood , Antibodies, Viral/blood , COVID-19/immunology , SARS-CoV-2/immunology , Aged , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , COVID-19/diagnosis , Coronavirus Nucleocapsid Proteins/immunology , Female , Follow-Up Studies , Hospitalization , Humans , Immunoglobulin Isotypes/blood , Immunoglobulin Isotypes/immunology , Kinetics , Male , Middle Aged , Models, Theoretical , Phosphoproteins/immunology , Protein Domains/immunology , SARS-CoV-2/isolation & purification , Seroconversion , Spike Glycoprotein, Coronavirus/immunology
2.
BMC Infect Dis ; 21(1): 357, 2021 Apr 16.
Article in English | MEDLINE | ID: covidwho-1315854

ABSTRACT

BACKGROUND: In 2020, a new coronavirus, SARS-CoV-2, quickly spread worldwide within a few months. Although coronaviruses typically infect the upper or lower respiratory tract, the virus RNA can be detected in plasma. The risk of transmitting coronavirus via transfusion of blood products remains. As more asymptomatic infections are identified in COVID-19 cases, blood safety has become particularly important. Methylene blue (MB) photochemical technology has been proven to inactivate lipid-enveloped viruses with high efficiency and safety. The present study aimed to investigate the SARS-CoV-2 inactivation effects of MB in plasma. METHODS: The SARS-CoV-2 virus strain was isolated from Zhejiang University. The live virus was harvested from cultured VERO-E6 cells, and mixed with MB in plasma. The MB final concentrations were 0, 1, 2, and 4 µM. The "BX-1 AIDS treatment instrument" was used at room temperature, the illumination adjusted to 55,000 ± 0.5 million Lux, and the plasma was irradiated for 0, 2, 5, 10, 20, and 40 mins using light at a single wavelength of 630 nm. Virus load changes were measured using quantitative reverse transcription- PCR. RESULTS: BX-1 could effectively eliminate SARS-CoV-2 within 2 mins in plasma, and the virus titer declined to 4.5 log10 TCID50 (median tissue culture infectious dose)/mL. CONCLUSION: BX-1 is based on MB photochemical technology, which was designed to inactivate HIV-1 virus in plasma. It was proven to be safe and reliable in clinical trials of HIV treatment. In this study, we showed that BX-1 could also be applied to inactivate SARS-CoV-2. During the current outbreak, this technique it has great potential for ensuring the safety of blood transfusions, for plasma transfusion therapy in recovering patients, and for preparing inactivated vaccines.


Subject(s)
Blood Safety , COVID-19/prevention & control , COVID-19/therapy , Methylene Blue/pharmacology , SARS-CoV-2/drug effects , Virus Inactivation , Animals , Blood Transfusion , Chlorocebus aethiops , Humans , Immunization, Passive , Plasma/virology , RNA, Viral , Vero Cells
4.
J Vet Diagn Invest ; 33(5): 969-974, 2021 Sep.
Article in English | MEDLINE | ID: covidwho-1298415

ABSTRACT

Avian influenza A(H5) viruses (avian IAVs) pose a major threat to the economy and public health. We developed an antigen-ELISA (ag-ELISA) and a colloidal gold-based immunochromatographic strip for the rapid detection of avian A(H5) viruses. Both detection methods displayed no cross-reactivity with other viruses (e.g., other avian IAVs, infectious bursal disease virus, Newcastle disease virus, infectious bronchitis virus, avian paramyxovirus). The ag-ELISA was sensitive down to 0.5 hemagglutinin (HA) units/100 µL of avian A(H5) viruses and 7.5 ng/mL of purified H5 HA proteins. The immunochromatographic strip was sensitive down to 1 HA unit/100 µL of avian A(H5) viruses. Both detection methods exhibited good reproducibility with CVs < 10%. For 200 random poultry samples, the sensitivity and specificity of the ag-ELISA were 92.6% and 98.8%, respectively, and for test strips were 88.9% and 98.3%, respectively. Both detection methods displayed high specificity, sensitivity, and stability, making them suitable for rapid detection and field investigation of avian A(H5) viruses.


Subject(s)
Infectious bronchitis virus , Influenza in Birds , Animals , Antibodies, Monoclonal , Antibodies, Viral , Chickens , Enzyme-Linked Immunosorbent Assay/veterinary , Gold Colloid , Influenza in Birds/diagnosis , Reproducibility of Results , Sensitivity and Specificity
5.
J Vet Diagn Invest ; 33(3): 577-581, 2021 May.
Article in English | MEDLINE | ID: covidwho-1271943

ABSTRACT

The H2 subtypes of avian influenza A viruses (avian IAVs) have been circulating in poultry, and they have the potential to infect humans. Therefore, establishing a method to quickly detect this subtype is pivotal. We developed a TaqMan minor groove binder real-time RT-PCR assay that involved probes and primers based on conserved sequences of the matrix and hemagglutinin genes. The detection limit of this assay was as low as one 50% egg infectious dose (EID50)/mL per reaction. This assay is specific, sensitive, and rapid for detecting avian IAV H2 subtypes.


Subject(s)
Influenza A virus/isolation & purification , Influenza in Birds/diagnosis , Real-Time Polymerase Chain Reaction/veterinary , Reverse Transcriptase Polymerase Chain Reaction/veterinary , Animals , Chick Embryo , Chickens , Real-Time Polymerase Chain Reaction/methods , Reverse Transcriptase Polymerase Chain Reaction/methods , Sensitivity and Specificity
6.
BMC Infect Dis ; 21(1): 357, 2021 Apr 16.
Article in English | MEDLINE | ID: covidwho-1190056

ABSTRACT

BACKGROUND: In 2020, a new coronavirus, SARS-CoV-2, quickly spread worldwide within a few months. Although coronaviruses typically infect the upper or lower respiratory tract, the virus RNA can be detected in plasma. The risk of transmitting coronavirus via transfusion of blood products remains. As more asymptomatic infections are identified in COVID-19 cases, blood safety has become particularly important. Methylene blue (MB) photochemical technology has been proven to inactivate lipid-enveloped viruses with high efficiency and safety. The present study aimed to investigate the SARS-CoV-2 inactivation effects of MB in plasma. METHODS: The SARS-CoV-2 virus strain was isolated from Zhejiang University. The live virus was harvested from cultured VERO-E6 cells, and mixed with MB in plasma. The MB final concentrations were 0, 1, 2, and 4 µM. The "BX-1 AIDS treatment instrument" was used at room temperature, the illumination adjusted to 55,000 ± 0.5 million Lux, and the plasma was irradiated for 0, 2, 5, 10, 20, and 40 mins using light at a single wavelength of 630 nm. Virus load changes were measured using quantitative reverse transcription- PCR. RESULTS: BX-1 could effectively eliminate SARS-CoV-2 within 2 mins in plasma, and the virus titer declined to 4.5 log10 TCID50 (median tissue culture infectious dose)/mL. CONCLUSION: BX-1 is based on MB photochemical technology, which was designed to inactivate HIV-1 virus in plasma. It was proven to be safe and reliable in clinical trials of HIV treatment. In this study, we showed that BX-1 could also be applied to inactivate SARS-CoV-2. During the current outbreak, this technique it has great potential for ensuring the safety of blood transfusions, for plasma transfusion therapy in recovering patients, and for preparing inactivated vaccines.


Subject(s)
Blood Safety , COVID-19/prevention & control , COVID-19/therapy , Methylene Blue/pharmacology , SARS-CoV-2/drug effects , Virus Inactivation , Animals , Blood Transfusion , Chlorocebus aethiops , Humans , Immunization, Passive , Plasma/virology , RNA, Viral , Vero Cells
7.
Cell Discov ; 6(1): 76, 2020 Oct 29.
Article in English | MEDLINE | ID: covidwho-904771

ABSTRACT

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread globally with more than 33 million patients diagnosed, taking more than a million lives. Abundant mutations were observed but the functional consequences of these mutations are largely unknown. We report the mutation spectrum, replication dynamics, and infectivity of 11 patient-derived viral isolates in diverse cell lines, including the human lung cancer cell line Calu-3. We observed 46 mutations, including 9 different mutations in the spike gene. Importantly, these viral isolates show significant and consistent variations in replication dynamics and infectivity in tested cell lines, up to a 1500-fold difference in viral titers at 24 h after infecting Calu-3 cells. Moreover, we show that the variations in viral titers among viral isolates are positively correlated with blood clotting function but inversely correlated with the amount of red blood cell and hemoglobin in patients. Therefore, we provide direct evidence that naturally occurring mutations in SARS-CoV-2 can substantially change its replication dynamics and infectivity in diverse human cell lines, with clinical implications in vivo.

8.
Emerg Microbes Infect ; 9(1): 1474-1488, 2020 Dec.
Article in English | MEDLINE | ID: covidwho-599992

ABSTRACT

The mutations in the SARS-CoV-2 virus genome during COVID-19 dissemination are unclear. In 788 COVID-19 patients from Zhejiang province, we observed decreased rate of severe/critical cases compared with patients in Wuhan. For mechanisms exploration, we isolated one strain of SARS-CoV-2 (ZJ01) from a mild COVID-19 patient. Thirty-five specific gene mutations were identified. Phylogenetic and relative synonymous codon usage analysis suggested that ZJ01 may be a potential evolutionary branch of SARS-CoV-2. We classified 54 global virus strains based on the base (C or T) at positions 8824 and 28247 while ZJ01 has T at both sites. The prediction of the Furin cleavage site (FCS) and sequence alignment indicated that the FCS may be an important site of coronavirus evolution. ZJ01 mutations identified near the FCS (F1-2) caused changes in the structure and electrostatic distribution of the S surface protein, further affecting the binding capacity of Furin. Single-cell sequencing and ACE2-Furin co-expression results confirmed that the Furin expression was especially higher in glands, liver, kidneys, and colon. The evolutionary pattern of SARS-CoV-2 towards FCS formation may result in its clinical symptom becoming closer to HKU-1 and OC43 caused mild flu-like symptoms, further showing its potential in differentiating into mild COVID-19 subtypes.


Subject(s)
Betacoronavirus/isolation & purification , Coronavirus Infections/virology , Furin/metabolism , Pneumonia, Viral/virology , Adult , Betacoronavirus/genetics , COVID-19 , China/epidemiology , Codon , Coronavirus Infections/complications , Coronavirus Infections/epidemiology , Disease Progression , Evolution, Molecular , Female , Humans , Male , Middle Aged , Mutation , Pandemics , Phylogeny , Pneumonia, Viral/complications , Pneumonia, Viral/epidemiology , Retrospective Studies , SARS-CoV-2 , Sequence Analysis, RNA
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