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1.
Sci Bull (Beijing) ; 67(13): 1372-1387, 2022 Jul 15.
Article in English | MEDLINE | ID: covidwho-1867754

ABSTRACT

Remarkable progress has been made in developing intramuscular vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2); however, they are limited with respect to eliciting local immunity in the respiratory tract, which is the primary infection site for SARS-CoV-2. To overcome the limitations of intramuscular vaccines, we constructed a nasal vaccine candidate based on an influenza vector by inserting a gene encoding the receptor-binding domain (RBD) of the spike protein of SARS-CoV-2, named CA4-dNS1-nCoV-RBD (dNS1-RBD). A preclinical study showed that in hamsters challenged 1 d after single-dose vaccination or 9 months after booster vaccination, dNS1-RBD largely mitigated lung pathology, with no loss of body weight. Moreover, such cellular immunity is relatively unimpaired for the most concerning SARS-CoV-2 variants, especially for the latest Omicron variant. In addition, this vaccine also provides cross-protection against H1N1 and H5N1 influenza viruses. The protective immune mechanism of dNS1-RBD could be attributed to the innate immune response in the nasal epithelium, local RBD-specific T cell response in the lung, and RBD-specific IgA and IgG response. Thus, this study demonstrates that the intranasally delivered dNS1-RBD vaccine candidate may offer an important addition to the fight against the ongoing coronavirus disease 2019 pandemic and influenza infection, compensating limitations of current intramuscular vaccines.

2.
Cell Rep ; 38(12): 110558, 2022 03 22.
Article in English | MEDLINE | ID: covidwho-1797096

ABSTRACT

Mutations in the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike receptor-binding domain (RBD) may alter viral host tropism and affect the activities of neutralizing antibodies. Here, we investigated 153 RBD mutants and 11 globally circulating variants of concern (VOCs) and variants of interest (VOIs) (including Omicron) for their antigenic changes and cross-species tropism in cells expressing 18 ACE2 orthologs. Several RBD mutations strengthened viral infectivity in cells expressing ACE2 orthologs of non-human animals, particularly those less susceptible to the ancestral strain. The mutations surrounding amino acids (aas) 439-448 and aa 484 are more likely to cause neutralization resistance. Strikingly, enhanced cross-species infection potential in the mouse and ferret, instead of the neutralization-escape scores of the mutations, account for the positive correlation with the cumulative prevalence of mutations in humans. These findings present insights for potential drivers of circulating SARS-CoV-2 variants and provide informative parameters for tracking and forecasting spreading mutations.


Subject(s)
COVID-19 , SARS-CoV-2 , Animals , Ferrets , Humans , Membrane Glycoproteins/metabolism , Mice , SARS-CoV-2/genetics , Spike Glycoprotein, Coronavirus , Tropism , Viral Envelope Proteins
3.
Am J Physiol Lung Cell Mol Physiol ; 322(5): L712-L721, 2022 05 01.
Article in English | MEDLINE | ID: covidwho-1759484

ABSTRACT

Accumulating evidence has confirmed that chronic obstructive pulmonary disease (COPD) is a risk factor for development of severe pathological changes in the peripheral lungs of patients with COVID-19. However, the underlying molecular mechanisms remain unclear. Because bronchiolar club cells are crucial for maintaining small airway homeostasis, we sought to explore whether the altered susceptibility to SARS-CoV-2 infection of the club cells might have contributed to the severe COVID-19 pneumonia in COPD patients. Our investigation on the quantity and distribution patterns of angiotensin-converting enzyme 2 (ACE2) in airway epithelium via immunofluorescence staining revealed that the mean fluorescence intensity of the ACE2-positive epithelial cells was significantly higher in club cells than those in other epithelial cells (including ciliated cells, basal cells, goblet cells, neuroendocrine cells, and alveolar type 2 cells). Compared with nonsmokers, the median percentage of club cells in bronchiolar epithelium and ACE2-positive club cells was significantly higher in COPD patients. In vitro, SARS-CoV-2 infection (at a multiplicity of infection of 1.0) of primary small airway epithelial cells, cultured on air-liquid interface, confirmed a higher percentage of infected ACE2-positive club cells in COPD patients than in nonsmokers. Our findings have indicated the role of club cells in modulating the pathogenesis of SARS-CoV-2-related severe pneumonia and the poor clinical outcomes, which may help physicians to formulate a novel therapeutic strategy for COVID-19 patients with coexisting COPD.


Subject(s)
COVID-19 , Pulmonary Disease, Chronic Obstructive , Angiotensin-Converting Enzyme 2 , Epithelial Cells , Humans , Lung , Peptidyl-Dipeptidase A , SARS-CoV-2
4.
Cell reports ; 2022.
Article in English | EuropePMC | ID: covidwho-1728589

ABSTRACT

Zhang et al. show in vitro cross-species infectivity and neutralization-escape characteristics of 153 SARS-CoV-2 RBD mutants and 11 globally circulating VOC/VOI variants. They reveal an association between enhanced cross-species infection potential and the current cumulative prevalence of mutations, which can inform surveillance and forecasting of SARS-CoV-2 spike mutations.

5.
EuropePMC; 2022.
Preprint in English | EuropePMC | ID: ppcovidwho-329405

ABSTRACT

Antibody therapeutics for the treatment of COVID-19 has been highly successful while faces a challenge of the recent emergence of the Omicron variant which escapes the majority of existing SARS-CoV-2 neutralizing antibodies (nAbs). Here, we successfully generated a panel of SARS-CoV-2/SARS-CoV cross-neutralizing antibodies by sequential immunization of the two pseudoviruses. Of which, nAbs X01, X10 and X17 showed broadly neutralizing breadths against most variants of concern (VOCs) and X17 was further identified as a Class 5 nAb with undiminished neutralization against the Omicron variant. Cryo-EM structures of three-antibody in complex with the spike proteins of prototyped SARS-CoV-2, Delta, Omicron and SARS-CoV defined three non-overlapping conserved epitopes on the receptor-binding domain (RBD). The triple antibody cocktail exhibited enhanced resistance to viral escape and effective protection against the infection of Beta variant in hamsters. Our finding will aid the development of both antibody therapeutics and broad vaccines against SARS-CoV-2 and emerging variants.

6.
EuropePMC;
Preprint in English | EuropePMC | ID: ppcovidwho-327136

ABSTRACT

The widespread SARS-CoV-2 in humans results in the continuous emergence of new variants. Recently emerged Omicron variant with multiple spike mutations sharply increases the risk of breakthrough infection or reinfection, highlighting the urgent need for new vaccines with broad-spectrum antigenic coverage. Using inter-lineage chimera and mutation patch strategies, we engineered a recombinant monomeric spike variant (STFK1628x), which showed high immunogenicity and mutually complementary antigenicity to its prototypic form (STFK). In hamsters, a bivalent vaccine comprised of STFK and STFK1628x elicited high titers of broad-spectrum antibodies to neutralize all 14 circulating SARS-CoV-2 variants, including Omicron;and fully protected vaccinees from intranasal SARS-CoV-2 challenges of either the ancestral strain or immune-evasive Beta variant. Strikingly, the vaccination of hamsters with the bivalent vaccine completely blocked the within-cage virus transmission to unvaccinated sentinels, for either the ancestral SARS-CoV-2 or Beta variant. Thus, our study provides new insights and antigen candidates for developing next-generation COVID-19 vaccines.

7.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-324812

ABSTRACT

Background: The pandemic of SARS-CoV-2 has turned into a global public health crisis. Acute SARS-CoV-2 infection is associated with severe pneumonia, multiple-organ failures and deaths. Currently, treatment for SARS-CoV-2 infection and severe pneumonia is largely lacking. Several clinical trials demonstrated that glucocorticoid dexamethasone is effective to reduce disease severity and mortality. However, whether dexamethasone is clinically sufficient to treat COVID-19 is unknown.Methods: We tested the therapeutic effect of dexamethasone on SARS-CoV-2 infection and pneumonia in a Syrian hamster model. Survival rate, body weight loss, viral RNA, antibody responses, severity of lung inflammation and injury were measured in a 7-day acute infection course.Findings: Dexamethasone reduces body weight loss and relieves the diffusion of lung injury in SARS-CoV-2-infected hamster by inhibiting the excessive proinflammatory cytokines including IL-4, IL-6, IL-10, IL-13, TNF-α and IFN-γ. Dexamethasone rescues hamsters from the lethal infection of SARS-CoV-2 variant D614G. Dexamethasone attenuates serum neutralizing antibody and RBD-specific antibody titers, and slightly increases viral RNA level in lung tissues.Interpretation: Overall, using the hamster model, this study improves our understanding of the therapeutic mechanisms and drawbacks of dexamethasone treatment of COVID-19, and suggests that an antiviral is needed to accompany the dexamethasone treatment regimen.Funding: National Science Key Research and Development Project of China, National Natural Science Foundation of China, the CAMS Innovation Fund for Medical Sciences and China Postdoctoral Science Foundation.Declaration of Interest: The authors declare no competing interests.Ethical Approval: All the animal experiments were approved by the Medical Ethics Committee(SUCM2021-112).

10.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-292884

ABSTRACT

Remarkable progress has been made in developing intramuscular vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2);however, they are limited with respect to eliciting local immunity in the respiratory tract, which is the primary infection site for SARS-CoV-2. To overcome the limitations of intramuscular vaccines, we constructed a nasal vaccine candidate based on an influenza vector by inserting a gene encoding the receptor-binding domain (RBD) of the spike protein of SARS-CoV-2, named CA4-dNS1-nCoV-RBD (dNS1-RBD). A preclinical study showed that in hamsters challenged 1 day and 7 days after single-dose vaccination or 6 months after booster vaccination, dNS1-RBD largely mitigated lung pathology, with no loss of body weight, caused by either the prototype-like strain or beta variant of SARS-CoV-2. Lasted data showed that the animals could be well protected against beta variant challenge 9 months after vaccination. Notably, the weight loss and lung pathological changes of hamsters could still be significantly reduced when the hamster was vaccinated 24 h after challenge. Moreover, such cellular immunity is relatively unimpaired for the most concerning SARS-CoV-2 variants. The protective immune mechanism of dNS1-RBD could be attributed to the innate immune response in the nasal epithelium, local RBD-specific T cell response in the lung, and RBD-specific IgA and IgG response. Thus, this study demonstrates that the intranasally delivered dNS1-RBD vaccine candidate may offer an important addition to fight against the ongoing COVID-19 pandemic, compensating limitations of current intramuscular vaccines, particularly at the start of an outbreak.

13.
Sci Transl Med ; 13(606)2021 08 11.
Article in English | MEDLINE | ID: covidwho-1319371

ABSTRACT

Multiple safe and effective vaccines that elicit immune responses against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are necessary to respond to the ongoing coronavirus disease 2019 (COVID-19) pandemic. Here, we developed a protein subunit vaccine composed of spike ectodomain protein (StriFK) plus a nitrogen bisphosphonate-modified zinc-aluminum hybrid adjuvant (FH002C). StriFK-FH002C generated substantially higher neutralizing antibody titers in mice, hamsters, and cynomolgus monkeys than those observed in plasma isolated from COVID-19 convalescent individuals. StriFK-FH002C also induced both TH1- and TH2-polarized helper T cell responses in mice. In hamsters, StriFK-FH002C immunization protected animals against SARS-CoV-2 challenge, as shown by the absence of virus-induced weight loss, fewer symptoms of disease, and reduced lung pathology. Vaccination of hamsters with StriFK-FH002C also reduced within-cage virus transmission to unvaccinated, cohoused hamsters. In summary, StriFK-FH002C represents an effective, protein subunit-based SARS-CoV-2 vaccine candidate.


Subject(s)
COVID-19 , Animals , Antibodies, Neutralizing , Antibodies, Viral , COVID-19 Vaccines , Cricetinae , Humans , Mice , Protein Subunits , SARS-CoV-2 , Spike Glycoprotein, Coronavirus/genetics
14.
Theranostics ; 11(13): 6607-6615, 2021.
Article in English | MEDLINE | ID: covidwho-1231569

ABSTRACT

SARS-CoV-2 infection, which is responsible for the current COVID-19 pandemic, can cause life-threatening pneumonia, respiratory failure and even death. Characterizing SARS-CoV-2 pathogenesis in primary human target cells and tissues is crucial for developing vaccines and therapeutics. However, given the limited access to clinical samples from COVID-19 patients, there is a pressing need for in vitro/in vivo models to investigate authentic SARS-CoV-2 infection in primary human lung cells or tissues with mature structures. The present study was designed to evaluate a humanized mouse model carrying human lung xenografts for SARS-CoV-2 infection in vivo. Methods: Human fetal lung tissue surgically grafted under the dorsal skin of SCID mice were assessed for growth and development after 8 weeks. Following SARS-CoV-2 inoculation into the differentiated lung xenografts, viral replication, cell-type tropism and histopathology of SARS-CoV-2 infection, and local cytokine/chemokine expression were determined over a 6-day period. The effect of IFN-α treatment against SARS-CoV-2 infection was tested in the lung xenografts. Results: Human lung xenografts expanded and developed mature structures closely resembling normal human lung. SARS-CoV-2 replicated and spread efficiently in the lung xenografts with the epithelial cells as the main target, caused severe lung damage, and induced a robust pro-inflammatory response. IFN-α treatment effectively inhibited SARS-CoV-2 replication in the lung xenografts. Conclusions: These data support the human lung xenograft mouse model as a useful and biological relevant tool that should facilitate studies on the pathogenesis of SARS-CoV-2 lung infection and the evaluation of potential antiviral therapies.


Subject(s)
COVID-19/immunology , Disease Models, Animal , Lung/pathology , Respiratory Mucosa/cytology , SARS-CoV-2/immunology , Aborted Fetus , Animals , COVID-19/pathology , COVID-19/virology , Cells, Cultured , Epithelial Cells/virology , Heterografts , Humans , Lung/immunology , Lung/virology , Lung Transplantation , Male , Mice , Mice, SCID , Primary Cell Culture , SARS-CoV-2/pathogenicity , Virus Replication
15.
Signal Transduct Target Ther ; 6(1): 136, 2021 03 31.
Article in English | MEDLINE | ID: covidwho-1164823

ABSTRACT

Epidemiological studies of the COVID-19 patients have suggested the male bias in outcomes of lung illness. To experimentally demonstrate the epidemiological results, we performed animal studies to infect male and female Syrian hamsters with SARS-CoV-2. Remarkably, high viral titer in nasal washings was detectable in male hamsters who presented symptoms of weight loss, weakness, piloerection, hunched back and abdominal respiration, as well as severe pneumonia, pulmonary edema, consolidation, and fibrosis. In contrast with the males, the female hamsters showed much lower shedding viral titers, moderate symptoms, and relatively mild lung pathogenesis. The obvious differences in the susceptibility to SARS-CoV-2 and severity of lung pathogenesis between male and female hamsters provided experimental evidence that SARS-CoV-2 infection and the severity of COVID-19 are associated with gender.


Subject(s)
COVID-19 , SARS-CoV-2/metabolism , Sex Characteristics , Animals , COVID-19/metabolism , COVID-19/pathology , Disease Models, Animal , Disease Susceptibility , Female , Male , Mesocricetus
16.
Nat Commun ; 12(1): 1383, 2021 03 02.
Article in English | MEDLINE | ID: covidwho-1114711

ABSTRACT

In this study, we investigate the seroprevalence of SARS-CoV-2 antibodies among blood donors in the cities of Wuhan, Shenzhen, and Shijiazhuang in China. From January to April 2020, 38,144 healthy blood donors in the three cities were tested for total antibody against SARS-CoV-2 followed by pseudotype SARS-CoV-2 neutralization tests, IgG, and IgM antibody testing. Finally, a total of 398 donors were confirmed positive. The age- and sex-standardized SARS-CoV-2 seroprevalence among 18-60 year-old adults (18-65 year-old in Shenzhen) was 2.66% (95% CI: 2.24%-3.07%) in Wuhan, 0.033% (95% CI: 0.0029%-0.267%) in Shenzhen, and 0.0028% (95% CI: 0.0001%-0.158%) in Shijiazhuang, respectively. Female sex and older-age were identified to be independent risk factors for SARS-CoV-2 seropositivity among blood donors in Wuhan. As most of the population of China remained uninfected during the early wave of the COVID-19 pandemic, effective public health measures are still certainly required to block viral spread before a vaccine is widely available.


Subject(s)
SARS-CoV-2/pathogenicity , Antibodies, Viral/blood , Blood Donors/statistics & numerical data , COVID-19/blood , COVID-19/epidemiology , COVID-19/immunology , China/epidemiology , Humans , Immunoglobulin G/blood , Immunoglobulin M/blood , Neutralization Tests , Prevalence , Risk Factors , SARS-CoV-2/immunology
17.
Front Pharmacol ; 11: 609592, 2020.
Article in English | MEDLINE | ID: covidwho-1094200

ABSTRACT

To identify drugs that are potentially used for the treatment of COVID-19, the potency of 1403 FDA-approved drugs were evaluated using a robust pseudovirus assay and the candidates were further confirmed by authentic SARS-CoV-2 assay. Four compounds, Clomiphene (citrate), Vortioxetine, Vortioxetine (hydrobromide) and Asenapine (hydrochloride), showed potent inhibitory effects in both pseudovirus and authentic virus assay. The combination of Clomiphene (citrate), Vortioxetine and Asenapine (hydrochloride) is much more potent than used alone, with IC50 of 0.34 µM.

18.
SciFinder; 2020.
Preprint | SciFinder | ID: ppcovidwho-5227

ABSTRACT

A review. The emergence of novel coronavirus pneumonia which was named as coronavirus disease 2019 (COVID-19) by the World Health Organization, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has posed a serious threat to public health.Notably, COVID-19 has rapidly spread around the world and large amount of people have been infected. There is imminent need to investigate the pathogenesis of SARS-CoV-2 and develop effective therapeutic strategies to contain the epidemic. The spike (S) protein of SARS-CoV-2 mediates viral entry into target cells, with S1 subunit binding to a cellular receptor and S2 subunit fusing viral and host membranes. Angiotensin-converting enzyme 2 (ACE2), previously known as a cell receptor of severe acute respiratory syndrome coronavirus (SARS-CoV), is putatively responsible for mediating COVID-19. In this review, we detail our current understanding of the interaction between S protein and ACE2 in the process of virus infection and the potential pathogenesis of SARS-CoV-2, which has critical implications for exploring the potential therapeutic strategies for COVID-19.

19.
Small Methods ; 5(2): 2001031, 2021 Feb 15.
Article in English | MEDLINE | ID: covidwho-986422

ABSTRACT

The ongoing corona virus disease 2019 (COVID-19) pandemic, caused by SARS-CoV-2 infection, has resulted in hundreds of thousands of deaths. Cellular entry of SARS-CoV-2, which is mediated by the viral spike protein and ACE2 receptor, is an essential target for the development of vaccines, therapeutic antibodies, and drugs. Using a mammalian cell expression system, a genetically engineered sensor of fluorescent protein (Gamillus)-fused SARS-CoV-2 spike trimer (STG) to probe the viral entry process is developed. In ACE2-expressing cells, it is found that the STG probe has excellent performance in the live-cell visualization of receptor binding, cellular uptake, and intracellular trafficking of SARS-CoV-2 under virus-free conditions. The new system allows quantitative analyses of the inhibition potentials and detailed influence of COVID-19-convalescent human plasmas, neutralizing antibodies and compounds, providing a versatile tool for high-throughput screening and phenotypic characterization of SARS-CoV-2 entry inhibitors. This approach may also be adapted to develop a viral entry visualization system for other viruses.

20.
Emerg Microbes Infect ; 9(1): 2105-2113, 2020 Dec.
Article in English | MEDLINE | ID: covidwho-913100

ABSTRACT

The global pandemic of coronavirus disease 2019 (COVID-19) is a disaster for human society. A convenient and reliable neutralization assay is very important for the development of vaccines and novel drugs. In this study, a G protein-deficient vesicular stomatitis virus (VSVdG) bearing a truncated spike protein (S with C-terminal 18 amino acid truncation) was compared to that bearing the full-length spike protein of SARS-CoV-2 and showed much higher efficiency. A neutralization assay was established based on VSV-SARS-CoV-2-Sdel18 pseudovirus and hACE2-overexpressing BHK21 cells (BHK21-hACE2 cells). The experimental results can be obtained by automatically counting the number of EGFP-positive cells at 12 h after infection, making the assay convenient and high-throughput. The serum neutralizing titer measured by the VSV-SARS-CoV-2-Sdel18 pseudovirus assay has a good correlation with that measured by the wild type SARS-CoV-2 assay. Seven neutralizing monoclonal antibodies targeting the receptor binding domain (RBD) of the SARS-CoV-2 S protein were obtained. This efficient and reliable pseudovirus assay model could facilitate the development of new drugs and vaccines.


Subject(s)
Antibodies, Neutralizing/blood , Antibodies, Viral/blood , Betacoronavirus/immunology , Coronavirus Infections/diagnosis , Neutralization Tests/methods , Pneumonia, Viral/diagnosis , Spike Glycoprotein, Coronavirus/immunology , Animals , Antibodies, Monoclonal/immunology , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , COVID-19 , Cell Line , Chlorocebus aethiops , Cricetinae , Pandemics , SARS-CoV-2 , Spike Glycoprotein, Coronavirus/genetics , Vero Cells , Vesicular stomatitis Indiana virus/genetics , Vesicular stomatitis Indiana virus/immunology
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