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2.
J Virol ; 96(4): e0155121, 2022 02 23.
Article in English | MEDLINE | ID: covidwho-1700556

ABSTRACT

Despite various attempts to treat severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-infected patients with COVID-19 convalescent plasmas, neither appropriate approach nor clinical utility has been established. We examined the efficacy of administration of highly neutralizing COVID-19 convalescent plasma (hn-plasmas) and such plasma-derived IgG administration using the Syrian hamster COVID-19 model. Two hn-plasmas, which were in the best 1% of 340 neutralizing activity-determined convalescent plasmas, were intraperitoneally administered to SARS-CoV-2-infected hamsters, resulting in a significant reduction of viral titers in lungs by up to 32-fold compared to the viral titers in hamsters receiving control nonneutralizing plasma, while with two moderately neutralizing plasmas (mn-plasmas) administered, viral titer reduction was by up to 6-fold. IgG fractions purified from the two hn-plasmas also reduced viral titers in lungs more than those from the two mn-plasmas. The severity of lung lesions seen in hamsters receiving hn-plasmas was minimal to moderate as assessed using microcomputerized tomography, which histological examination confirmed. Western blotting revealed that all four COVID-19 convalescent plasmas variably contained antibodies against SARS-CoV-2 components, including the receptor-binding domain and S1 domain. The present data strongly suggest that administering potent neutralizing activity-confirmed COVID-19 convalescent plasmas would be efficacious in treating patients with COVID-19. IMPORTANCE Convalescent plasmas obtained from patients who recovered from a specific infection have been used as agents to treat other patients infected with the very pathogen. To treat using convalescent plasmas, despite that more than 10 randomized controlled clinical trials have been conducted and more than 100 studies are currently ongoing, the effects of convalescent plasma against COVID-19 remained uncertain. On the other hand, certain COVID-19 vaccines have been shown to reduce the clinical COVID-19 onset by 94 to 95%, for which the elicited SARS-CoV-2-neutralizing antibodies are apparently directly responsible. Here, we demonstrate that highly neutralizing effect-confirmed convalescent plasmas significantly reduce the viral titers in the lung of SARS-CoV-2-infected Syrian hamsters and block the development of virally induced lung lesions. The present data provide a proof of concept that the presence of highly neutralizing antibody in COVID-19 convalescent plasmas is directly responsible for the reduction of viral replication and support the use of highly neutralizing antibody-containing plasmas in COVID-19 therapy with convalescent plasmas.


Subject(s)
COVID-19/therapy , Lung , SARS-CoV-2/physiology , Virus Replication , Animals , COVID-19/metabolism , Chlorocebus aethiops , Disease Models, Animal , Humans , Immunization, Passive , Lung/metabolism , Lung/virology , Male , Mesocricetus , Vero Cells
3.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-324400

ABSTRACT

Angiotensin-converting enzyme 2 (ACE2) is a receptor for cell entry of SARS-CoV-2, and recombinant soluble ACE2 protein inhibits SARS-CoV-2 infection as a decoy. ACE2 is a carboxypeptidase that degrades angiotensin II (Ang II) to angiotensin 1-7 (Ang 1-7) and thereby improves the pathologies of cardiovascular disease or acute lung injury. To address whether the carboxypeptidase activity of ACE2 is protective in COVID-19, we investigated the effects of B38-CAP, an ACE2-like enzyme, on SARS-CoV-2-induced lung injury. Expression of endogenous ACE2 protein was significantly downregulated in the lungs of SARS-CoV-2-infected hamsters or SARS-CoV-2 challenged human ACE2 transgenic mice, leading to elevation of Ang II levels. In vivo administration of recombinant SARS-CoV-2 Spike also downregulated ACE2 expression, elevated Ang II levels and considerably worsened the symptoms of acute lung injury in hamsters exposed to acid aspiration. Despite its ACE2-like catalytic core, B38-CAP neither bound to Spike nor neutralized cell entry of SARS-CoV-2. However, treatment with B38-CAP improved the pathologies of Spike-augmented acid-induced lung injury. In SARS-CoV-2-infected hamsters, B38-CAP significantly improved lung edema and pathologies of lung injury and downregulated IL-6 levels without affecting viral RNA loads. Moreover, in human ACE2 transgenic mice, B38-CAP also attenuated SARS-CoV-2-induced lung edema and pathologies and improved lung functions. These results provide the first experimental in vivo evidence that increasing ACE2-like enzymatic activity is a potential therapeutic strategy to alleviate lung pathologies in COVID-19.

4.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-318264

ABSTRACT

We developed an intranasal vaccine against SARS-CoV-2 using the replication-incompetent human parainfluenza virus type 2 (hPIV2) vector BC-PIV, which can deliver ectopic gene as stable RNA and ectopic protein on the envelope. BC-PIV expressing the full-length prefusion-stabilized spike gene of SARS-CoV-2, S2PM, possessed a corona-like viral envelope. Intranasal vaccination of mice with BC-PIV/S2PM induced high levels of neutralizing IgG and mucosal IgA antibodies against the spike protein. While BC-PIV showed hemagglutinating activity, BC-PIV/S2PM lacked such activity, in accordance with the presence of the massive spike protein on the viral surface. Furthermore, single-dose intranasal vaccination of hamsters with BC-PIV/S2PM completely protected the lungs from SARS-CoV-2 at 11 weeks post-immunization, and prime-boost vaccination conferred virtually complete protection of the nasal turbinates against SARS-CoV-2 challenge at 11 weeks post-priming. Thus, this chimeric hPIV2/spike intranasal vaccine is one of the strong candidates for an ultimate vaccine against SARS-CoV-2 to curtail virus transmission.Funding: This work was supported in part by Grants-in-Aid from the Ministry of Education, Culture, Sports, Science and Technology in Japan (17K19652, 20K21614), by a Research Program on Emerging and Re-emerging Infectious Diseases from the Japan Agency for Medical Research and Development (AMED) (JP19fk0108113), Mie University (for research institutes of excellence), Mie Prefecture, Junior Chamber International Yokkaichi, and MediciNova, Inc.Conflict of Interest: J.O., M.F., M.Im., R.O., S.Y., Y.Kaw., and T.N. are patent applicants for recombinant BCPIV vaccine against SARS-CoV-2. M.F. is a founder of BioComo, Inc., and J.O. is an employee of BioComo, Inc. J.O., M.F., M.M., and T.N. have shares of stock in Biocomo, Inc. M.M. is a scientific advisor of JEOL Ltd. T.N. is a scientific advisor of MediciNova, Inc. The other authors declare no competing interests.Ethical Approval: Recombinant DNA experiments with SARS-CoV-2 S gene fragments were approved by the Ministry of Education, Culture, Sports, Science and Technology in Japan (Approved No. 2019-728, 729;2020-362, 373, 948). The animal studies were approved by the Animal Care Committees of Mie University(Approved No. 23-33) and the Animal Experiment Committee of the Institute of Medical Science, the University of Tokyo (Approved No. PA19-75), and all methods were performed under institutional regulations of animal experiments in accordance with the current national guidelines. Animal experiments using SARS-CoV-2 S gene fragments orSARS-CoV-2 were also approved by the Ministry of Education, Culture, Sports, Science and Technology in Japan (Approved No. 2019-728, 729;2020-362, 373, 2020-948).

5.
mBio ; : e0304421, 2022 Feb 01.
Article in English | MEDLINE | ID: covidwho-1662302

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread worldwide since December 2019, causing coronavirus disease 2019 (COVID-19). Although vaccines for this virus have been developed rapidly, repurposing drugs approved to treat other diseases remains an invaluable treatment strategy. Here, we evaluated the inhibitory effects of drugs on SARS-CoV-2 replication in a hamster infection model and in in vitro assays. Favipiravir significantly suppressed virus replication in hamster lungs. Remdesivir inhibited virus replication in vitro, but was not effective in the hamster model. However, GS-441524, a metabolite of remdesivir, effectively suppressed virus replication in hamsters. Co-administration of favipiravir and GS-441524 more efficiently reduced virus load in hamster lungs than did single administration of either drug for both the prophylactic and therapeutic regimens; prophylactic co-administration also efficiently inhibited lung inflammation in the infected animals. Furthermore, pretreatment of hamsters with favipiravir and GS-441524 effectively protected them from virus transmission via respiratory droplets upon exposure to infected hamsters. Repurposing and co-administration of antiviral drugs may help combat COVID-19. IMPORTANCE During a pandemic, repurposing drugs that are approved for other diseases is a quick and realistic treatment option. In this study, we found that co-administration of favipiravir and the remdesivir metabolite GS-441524 more effectively blocked SARS-CoV-2 replication in the lungs of Syrian hamsters than either favipiravir or GS-441524 alone as part of a prophylactic or therapeutic regimen. Prophylactic co-administration also reduced the severity of lung inflammation. Moreover, co-administration of these drugs to naive hamsters efficiently protected them from airborne transmission of the virus from infected animals. Since both drugs are nucleotide analogs that interfere with the RNA-dependent RNA polymerases of many RNA viruses, these findings may also help encourage co-administration of antivirals to combat future pandemics.

7.
PLoS Pathog ; 17(12): e1010085, 2021 12.
Article in English | MEDLINE | ID: covidwho-1559373

ABSTRACT

Regulatory T (Treg) cells, which constitute about 5-10% of CD4+T cells expressing Foxp3 transcription factor and CD25(IL-2 receptor α chain), are key regulators in controlling immunological self-tolerance and various immune responses. However, how Treg cells control antigen-specific immunity to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) remains unclear. In this study, we examined the effect of transient breakdown of the immunological tolerance induced by Treg-cell depletion on adaptive immune responses against administered SARS-CoV-2 antigen, spike protein 1 (S1). Notably, without the use of adjuvants, transient Treg-cell depletion in mice induced anti-S1 antibodies that neutralized authentic SARS-CoV-2, follicular helper T cell formation and S1-binding germinal center B cell responses, but prevented the onset of developing autoimmune diseases. To further clarify the mechanisms, we investigated maturation of dendritic cells (DCs), which is essential to initiate antigen-specific immunity. We found that the transient Treg-cell depletion resulted in maturation of both migratory and resident DCs in draining lymph nodes that captured S1-antigen. Moreover, we observed S1-specific CD4+ T cells and CD8+ T cells with interferon-γ production. Thus, captured S1 was successfully presented by DCs, including cross-presentation to CD8+ T cells. These data indicate that transient Treg-cell depletion in the absence of adjuvants induces maturation of antigen-presenting DCs and succeeds in generating antigen-specific humoral and cellular immunity against emerging SARS-CoV-2 antigens. Finally, we showed that SARS-CoV-2 antigen-specific immune responses induced by transient Treg-cell depletion in the absence of adjuvants were compatible with those induced with an effective adjuvant, polyriboinosinic:polyribocytidyl acid (poly IC) and that the combination of transient Treg-cell depletion with poly IC induced potent responses. These findings highlight the capacity for manipulating Treg cells to induce protective adaptive immunity to SARS-CoV-2 with activating antigen-presenting DCs, which may improve the efficacy of ongoing vaccine therapies and help enhance responses to emerging SARS-CoV-2 variants.


Subject(s)
Adaptive Immunity/immunology , Antigens, Viral/immunology , COVID-19/immunology , Forkhead Transcription Factors/immunology , SARS-CoV-2/immunology , Animals , Antigen Presentation/immunology , CD4-Positive T-Lymphocytes/immunology , CD8-Positive T-Lymphocytes/immunology , COVID-19/virology , Chlorocebus aethiops , Dendritic Cells/immunology , Female , Germinal Center/immunology , Humans , Immune Tolerance , Mice , Mice, Inbred C57BL , Mice, Inbred MRL lpr , T-Lymphocytes, Regulatory/immunology , Vero Cells
8.
J Virol ; 96(4): e0155121, 2022 02 23.
Article in English | MEDLINE | ID: covidwho-1532963

ABSTRACT

Despite various attempts to treat severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-infected patients with COVID-19 convalescent plasmas, neither appropriate approach nor clinical utility has been established. We examined the efficacy of administration of highly neutralizing COVID-19 convalescent plasma (hn-plasmas) and such plasma-derived IgG administration using the Syrian hamster COVID-19 model. Two hn-plasmas, which were in the best 1% of 340 neutralizing activity-determined convalescent plasmas, were intraperitoneally administered to SARS-CoV-2-infected hamsters, resulting in a significant reduction of viral titers in lungs by up to 32-fold compared to the viral titers in hamsters receiving control nonneutralizing plasma, while with two moderately neutralizing plasmas (mn-plasmas) administered, viral titer reduction was by up to 6-fold. IgG fractions purified from the two hn-plasmas also reduced viral titers in lungs more than those from the two mn-plasmas. The severity of lung lesions seen in hamsters receiving hn-plasmas was minimal to moderate as assessed using microcomputerized tomography, which histological examination confirmed. Western blotting revealed that all four COVID-19 convalescent plasmas variably contained antibodies against SARS-CoV-2 components, including the receptor-binding domain and S1 domain. The present data strongly suggest that administering potent neutralizing activity-confirmed COVID-19 convalescent plasmas would be efficacious in treating patients with COVID-19. IMPORTANCE Convalescent plasmas obtained from patients who recovered from a specific infection have been used as agents to treat other patients infected with the very pathogen. To treat using convalescent plasmas, despite that more than 10 randomized controlled clinical trials have been conducted and more than 100 studies are currently ongoing, the effects of convalescent plasma against COVID-19 remained uncertain. On the other hand, certain COVID-19 vaccines have been shown to reduce the clinical COVID-19 onset by 94 to 95%, for which the elicited SARS-CoV-2-neutralizing antibodies are apparently directly responsible. Here, we demonstrate that highly neutralizing effect-confirmed convalescent plasmas significantly reduce the viral titers in the lung of SARS-CoV-2-infected Syrian hamsters and block the development of virally induced lung lesions. The present data provide a proof of concept that the presence of highly neutralizing antibody in COVID-19 convalescent plasmas is directly responsible for the reduction of viral replication and support the use of highly neutralizing antibody-containing plasmas in COVID-19 therapy with convalescent plasmas.


Subject(s)
COVID-19/therapy , Lung , SARS-CoV-2/physiology , Virus Replication , Animals , COVID-19/metabolism , Chlorocebus aethiops , Disease Models, Animal , Humans , Immunization, Passive , Lung/metabolism , Lung/virology , Male , Mesocricetus , Vero Cells
9.
Nature ; 602(7896): 300-306, 2022 02.
Article in English | MEDLINE | ID: covidwho-1532072

ABSTRACT

During the current coronavirus disease 2019 (COVID-19) pandemic, a variety of mutations have accumulated in the viral genome of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and, at the time of writing, four variants of concern are considered to be potentially hazardous to human society1. The recently emerged B.1.617.2/Delta variant of concern is closely associated with the COVID-19 surge that occurred in India in the spring of 2021 (ref. 2). However, the virological properties of B.1.617.2/Delta remain unclear. Here we show that the B.1.617.2/Delta variant is highly fusogenic and notably more pathogenic than prototypic SARS-CoV-2 in infected hamsters. The P681R mutation in the spike protein, which is highly conserved in this lineage, facilitates cleavage of the spike protein and enhances viral fusogenicity. Moreover, we demonstrate that the P681R-bearing virus exhibits higher pathogenicity compared with its parental virus. Our data suggest that the P681R mutation is a hallmark of the virological phenotype of the B.1.617.2/Delta variant and is associated with enhanced pathogenicity.


Subject(s)
COVID-19/virology , Membrane Fusion , Mutation , SARS-CoV-2/genetics , SARS-CoV-2/pathogenicity , Spike Glycoprotein, Coronavirus/genetics , Amino Acid Substitution , Animals , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , COVID-19/epidemiology , Cricetinae , Giant Cells/metabolism , Giant Cells/virology , Male , Mesocricetus , Phylogeny , SARS-CoV-2/immunology , SARS-CoV-2/metabolism , Virulence/genetics , Virus Replication
10.
Nat Commun ; 12(1): 6791, 2021 11 23.
Article in English | MEDLINE | ID: covidwho-1532053

ABSTRACT

Angiotensin-converting enzyme 2 (ACE2) is a receptor for cell entry of SARS-CoV-2, and recombinant soluble ACE2 protein inhibits SARS-CoV-2 infection as a decoy. ACE2 is a carboxypeptidase that degrades angiotensin II, thereby improving the pathologies of cardiovascular disease or acute lung injury. Here we show that B38-CAP, an ACE2-like enzyme, is protective against SARS-CoV-2-induced lung injury. Endogenous ACE2 expression is downregulated in the lungs of SARS-CoV-2-infected hamsters, leading to elevation of angiotensin II levels. Recombinant Spike also downregulates ACE2 expression and worsens the symptoms of acid-induced lung injury. B38-CAP does not neutralize cell entry of SARS-CoV-2. However, B38-CAP treatment improves the pathologies of Spike-augmented acid-induced lung injury. In SARS-CoV-2-infected hamsters or human ACE2 transgenic mice, B38-CAP significantly improves lung edema and pathologies of lung injury. These results provide the first in vivo evidence that increasing ACE2-like enzymatic activity is a potential therapeutic strategy to alleviate lung pathologies in COVID-19 patients.


Subject(s)
Angiotensin-Converting Enzyme 2/metabolism , COVID-19/drug therapy , COVID-19/prevention & control , Lung Injury/prevention & control , SARS-CoV-2/drug effects , Virus Internalization/drug effects , Acute Lung Injury , Angiotensin II , Animals , COVID-19/pathology , Carboxypeptidases , Chlorocebus aethiops , Cricetinae , Disease Models, Animal , Female , Humans , Lung/pathology , Male , Mice , Mice, Transgenic , Pulmonary Edema/pathology , Pulmonary Edema/prevention & control , Spike Glycoprotein, Coronavirus/drug effects , Vero Cells
11.
iScience ; 24(12): 103379, 2021 Dec 17.
Article in English | MEDLINE | ID: covidwho-1517302

ABSTRACT

We developed an intranasal vaccine against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) using the replication-incompetent human parainfluenza virus type 2 (hPIV2) vector BC-PIV, which can deliver ectopic gene as stable RNA and ectopic protein on the envelope. BC-PIV expressing the full-length prefusion-stabilized spike gene (K986P/V987P) of SARS-CoV-2, S-2PM, possessed a corona-like viral envelope. Intranasal vaccination of mice with BC-PIV/S-2PM induced high levels of neutralizing immunoglobulin G (IgG) and mucosal IgA antibodies against the spike protein. Although BC-PIV showed hemagglutinating activity, BC-PIV/S-2PM lacked such activity, in accordance with the presence of the massive spike protein on the viral surface. Furthermore, single-dose intranasal vaccination of hamsters with BC-PIV/S-2PM completely protected the lungs from SARS-CoV-2 at 11-week post-immunization, and boost vaccination two weeks before the challenge conferred virtually complete protection of the nasal turbinates against SARS-CoV-2. Thus, this chimeric hPIV2/spike intranasal vaccine is a promising vaccine candidate for SARS-CoV-2 to curtail virus transmission.

12.
Nihon Naika Gakkai Zasshi ; 109(11):2260-2263, 2020.
Article in Japanese | J-STAGE | ID: covidwho-1511914
14.
Translational and Regulatory Sciences ; : 2021-012, 2021.
Article in Japanese | J-STAGE | ID: covidwho-1353067
15.
Proc Natl Acad Sci U S A ; 118(27)2021 07 06.
Article in English | MEDLINE | ID: covidwho-1276013

ABSTRACT

The spike (S) protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) plays a key role in viral infectivity. It is also the major antigen stimulating the host's protective immune response, specifically, the production of neutralizing antibodies. Recently, a new variant of SARS-CoV-2 possessing multiple mutations in the S protein, designated P.1, emerged in Brazil. Here, we characterized a P.1 variant isolated in Japan by using Syrian hamsters, a well-established small animal model for the study of SARS-CoV-2 disease (COVID-19). In hamsters, the variant showed replicative abilities and pathogenicity similar to those of early and contemporary strains (i.e., SARS-CoV-2 bearing aspartic acid [D] or glycine [G] at position 614 of the S protein). Sera and/or plasma from convalescent patients and BNT162b2 messenger RNA vaccinees showed comparable neutralization titers across the P.1 variant, S-614D, and S-614G strains. In contrast, the S-614D and S-614G strains were less well recognized than the P.1 variant by serum from a P.1-infected patient. Prior infection with S-614D or S-614G strains efficiently prevented the replication of the P.1 variant in the lower respiratory tract of hamsters upon reinfection. In addition, passive transfer of neutralizing antibodies to hamsters infected with the P.1 variant or the S-614G strain led to reduced virus replication in the lower respiratory tract. However, the effect was less pronounced against the P.1 variant than the S-614G strain. These findings suggest that the P.1 variant may be somewhat antigenically different from the early and contemporary strains of SARS-CoV-2.


Subject(s)
COVID-19/virology , SARS-CoV-2/physiology , SARS-CoV-2/pathogenicity , Virus Replication , Animals , Antibodies, Neutralizing , COVID-19/diagnostic imaging , COVID-19/pathology , Cricetinae , Humans , Immunogenicity, Vaccine , Lung/pathology , Mesocricetus , Mice , Spike Glycoprotein, Coronavirus/genetics , X-Ray Microtomography
17.
Viruses ; 12(6)2020 06 10.
Article in English | MEDLINE | ID: covidwho-1120057

ABSTRACT

Although infection by SARS-CoV-2, the causative agent of coronavirus pneumonia disease (COVID-19), is spreading rapidly worldwide, no drug has been shown to be sufficiently effective for treating COVID-19. We previously found that nafamostat mesylate, an existing drug used for disseminated intravascular coagulation (DIC), effectively blocked Middle East respiratory syndrome coronavirus (MERS-CoV) S protein-mediated cell fusion by targeting transmembrane serine protease 2 (TMPRSS2), and inhibited MERS-CoV infection of human lung epithelium-derived Calu-3 cells. Here we established a quantitative fusion assay dependent on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) S protein, angiotensin I converting enzyme 2 (ACE2) and TMPRSS2, and found that nafamostat mesylate potently inhibited the fusion while camostat mesylate was about 10-fold less active. Furthermore, nafamostat mesylate blocked SARS-CoV-2 infection of Calu-3 cells with an effective concentration (EC)50 around 10 nM, which is below its average blood concentration after intravenous administration through continuous infusion. On the other hand, a significantly higher dose (EC50 around 30 mM) was required for VeroE6/TMPRSS2 cells, where the TMPRSS2-independent but cathepsin-dependent endosomal infection pathway likely predominates. Together, our study shows that nafamostat mesylate potently inhibits SARS-CoV-2 S protein-mediated fusion in a cell fusion assay system and also inhibits SARS-CoV-2 infection in vitro in a cell-type-dependent manner. These findings, together with accumulated clinical data regarding nafamostat's safety, make it a likely candidate drug to treat COVID-19.


Subject(s)
Anticoagulants/pharmacology , Betacoronavirus/drug effects , Coronavirus Infections/drug therapy , Guanidines/pharmacology , Pneumonia, Viral/drug therapy , Spike Glycoprotein, Coronavirus/antagonists & inhibitors , Virus Internalization/drug effects , Angiotensin-Converting Enzyme 2 , Angiotensin-Converting Enzyme Inhibitors/pharmacology , Animals , Benzamidines , Betacoronavirus/metabolism , COVID-19 , Cell Line , Chlorocebus aethiops , Coronavirus Infections/virology , Esters , Gabexate/analogs & derivatives , Gabexate/pharmacology , HEK293 Cells , Humans , Pandemics , Peptidyl-Dipeptidase A/metabolism , Pneumonia, Viral/virology , SARS-CoV-2 , Serine Endopeptidases/metabolism , Spike Glycoprotein, Coronavirus/metabolism , Vero Cells
18.
Sci Adv ; 7(10)2021 03.
Article in English | MEDLINE | ID: covidwho-1119272

ABSTRACT

Limited knowledge exists on immune markers associated with disease severity or recovery in patients with coronavirus disease 2019 (COVID-19). Here, we elucidated longitudinal evolution of SARS-CoV-2 antibody repertoire in patients with acute COVID-19. Differential kinetics was observed for immunoglobulin M (IgM)/IgG/IgA epitope diversity, antibody binding, and affinity maturation in "severe" versus "mild" COVID-19 patients. IgG profile demonstrated immunodominant antigenic sequences encompassing fusion peptide and receptor binding domain (RBD) in patients with mild COVID-19 who recovered early compared with "fatal" COVID-19 patients. In patients with severe COVID-19, high-titer IgA were observed, primarily against RBD, especially in patients who succumbed to SARS-CoV-2 infection. The patients with mild COVID-19 showed marked increase in antibody affinity maturation to prefusion SARS-CoV-2 spike that associated with faster recovery from COVID-19. This study revealed antibody markers associated with disease severity and resolution of clinical disease that could inform development and evaluation of effective immune-based countermeasures against COVID-19.


Subject(s)
Antibodies, Viral/blood , Antibodies, Viral/immunology , Antigens, Viral/immunology , Biomarkers/blood , COVID-19/immunology , COVID-19/pathology , SARS-CoV-2/physiology , Severity of Illness Index , Antibody Affinity/immunology , Antibody Formation/immunology , COVID-19/blood , COVID-19/virology , Cytokines/blood , HEK293 Cells , Hospitalization , Humans , Immunoglobulin Class Switching , Kinetics , Neutralization Tests , Protein Binding , Protein Domains , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/immunology , Viral Load
19.
Viruses ; 12(12)2020 12 10.
Article in English | MEDLINE | ID: covidwho-970091

ABSTRACT

Reverse transcription-quantitative PCR (RT-qPCR)-based tests are widely used to diagnose coronavirus disease 2019 (COVID-19). As a result that these tests cannot be done in local clinics where RT-qPCR testing capability is lacking, rapid antigen tests (RATs) for COVID-19 based on lateral flow immunoassays are used for rapid diagnosis. However, their sensitivity compared with each other and with RT-qPCR and infectious virus isolation has not been examined. Here, we compared the sensitivity among four RATs by using severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) isolates and several types of COVID-19 patient specimens and compared their sensitivity with that of RT-qPCR and infectious virus isolation. Although the RATs read the samples containing large amounts of virus as positive, even the most sensitive RAT read the samples containing small amounts of virus as negative. Moreover, all RATs tested failed to detect viral antigens in several specimens from which the virus was isolated. The current RATs will likely miss some COVID-19 patients who are shedding infectious SARS-CoV-2.


Subject(s)
Antigens, Viral/analysis , COVID-19 Serological Testing/methods , COVID-19/diagnosis , Point-of-Care Systems , SARS-CoV-2/isolation & purification , False Negative Reactions , Humans , Immunoassay , Real-Time Polymerase Chain Reaction , SARS-CoV-2/immunology , Sensitivity and Specificity , Specimen Handling
20.
mSphere ; 5(5)2020 10 21.
Article in English | MEDLINE | ID: covidwho-889855

ABSTRACT

Guidelines from the CDC and the WHO recommend the wearing of face masks to prevent the spread of coronavirus (CoV) disease 2019 (COVID-19); however, the protective efficiency of such masks against airborne transmission of infectious severe acute respiratory syndrome CoV-2 (SARS-CoV-2) droplets/aerosols is unknown. Here, we developed an airborne transmission simulator of infectious SARS-CoV-2-containing droplets/aerosols produced by human respiration and coughs and assessed the transmissibility of the infectious droplets/aerosols and the ability of various types of face masks to block the transmission. We found that cotton masks, surgical masks, and N95 masks all have a protective effect with respect to the transmission of infective droplets/aerosols of SARS-CoV-2 and that the protective efficiency was higher when masks were worn by a virus spreader. Importantly, medical masks (surgical masks and even N95 masks) were not able to completely block the transmission of virus droplets/aerosols even when completely sealed. Our data will help medical workers understand the proper use and performance of masks and determine whether they need additional equipment to protect themselves from infected patients.IMPORTANCE Airborne simulation experiments showed that cotton masks, surgical masks, and N95 masks provide some protection from the transmission of infective SARS-CoV-2 droplets/aerosols; however, medical masks (surgical masks and even N95 masks) could not completely block the transmission of virus droplets/aerosols even when sealed.


Subject(s)
Aerosols , Air Microbiology , Coronavirus Infections/prevention & control , Coronavirus Infections/transmission , Masks/standards , Pandemics/prevention & control , Pneumonia, Viral/prevention & control , Pneumonia, Viral/transmission , Betacoronavirus , COVID-19 , Health Personnel/education , Humans , Masks/classification , SARS-CoV-2
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