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EuropePMC; 2020.
Preprint in English | EuropePMC | ID: ppcovidwho-311717


The Coronavirus Disease of 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) threatens global public health and economy. Therapeutic options such as monoclonal antibodies (mAbs) against SARS-CoV-2 are in urgent need. We have identified potent monoclonal antibodies binding to SARS-CoV-2 Spike protein from COVID-19 convalescent patients and one of these antibodies, P4A1, interacts directly and covers the majority of the Receptor Binding Motif (RBM) of Spike receptor-binding domain (RBD), shown by high-resolution complex structure analysis. We further demonstrated P4A1 binding and neutralizing activities against wild type and mutant spike proteins. P4A1 was subsequently engineered to reduce the potential risk for antibody-dependent enhancement (ADE) of infection and to extend its half-life. The engineered mAb exhibits optimized pharmacokinetic and safety profile, and results in complete viral clearance in a rhesus monkey model of COVID-19 following a single injection.

Signal Transduct Target Ther ; 5(1): 218, 2020 10 03.
Article in English | MEDLINE | ID: covidwho-1387198

Antiviral Agents/pharmacology , Betacoronavirus/drug effects , Cardiac Glycosides/pharmacology , Gene Expression Regulation/drug effects , Host-Pathogen Interactions/drug effects , Animals , Antiviral Agents/chemistry , Betacoronavirus/pathogenicity , Biological Products/chemistry , Biological Products/pharmacology , Bufanolides/chemistry , Bufanolides/pharmacology , COVID-19 , Cardiac Glycosides/chemistry , Cell Survival/drug effects , Chlorocebus aethiops , Chloroquine/chemistry , Chloroquine/pharmacology , Coronavirus Infections/drug therapy , Coronavirus Infections/virology , Digoxin/chemistry , Digoxin/pharmacology , High-Throughput Screening Assays , Host-Pathogen Interactions/genetics , Humans , Janus Kinases/antagonists & inhibitors , Janus Kinases/genetics , Janus Kinases/metabolism , Mitogen-Activated Protein Kinases/antagonists & inhibitors , Mitogen-Activated Protein Kinases/genetics , Mitogen-Activated Protein Kinases/metabolism , NF-E2-Related Factor 2/antagonists & inhibitors , NF-E2-Related Factor 2/genetics , NF-E2-Related Factor 2/metabolism , NF-kappa B/antagonists & inhibitors , NF-kappa B/genetics , NF-kappa B/metabolism , Pandemics , Phenanthrenes/chemistry , Phenanthrenes/pharmacology , Pneumonia, Viral/drug therapy , Pneumonia, Viral/virology , SARS-CoV-2 , Signal Transduction , Sodium-Potassium-Exchanging ATPase/antagonists & inhibitors , Sodium-Potassium-Exchanging ATPase/genetics , Sodium-Potassium-Exchanging ATPase/metabolism , Vero Cells , Virus Replication/drug effects
Virol Sin ; 36(5): 879-889, 2021 Oct.
Article in English | MEDLINE | ID: covidwho-1174014


The ongoing coronavirus disease 2019 (COVID-19) pandemic caused more than 96 million infections and over 2 million deaths worldwide so far. However, there is no approved vaccine available for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the disease causative agent. Vaccine is the most effective approach to eradicate a pathogen. The tests of safety and efficacy in animals are pivotal for developing a vaccine and before the vaccine is applied to human populations. Here we evaluated the safety, immunogenicity, and efficacy of an inactivated vaccine based on the whole viral particles in human ACE2 transgenic mouse and in non-human primates. Our data showed that the inactivated vaccine successfully induced SARS-CoV-2-specific neutralizing antibodies in mice and non-human primates, and subsequently provided partial (in low dose) or full (in high dose) protection of challenge in the tested animals. In addition, passive serum transferred from vaccine-immunized mice could also provide full protection from SARS-CoV-2 infection in mice. These results warranted positive outcomes in future clinical trials in humans.

COVID-19 Vaccines/immunology , COVID-19 , Animals , Antibodies, Neutralizing/blood , Antibodies, Viral/blood , COVID-19/prevention & control , Mice , Mice, Transgenic , Primates , SARS-CoV-2 , Spike Glycoprotein, Coronavirus , Vaccines, Inactivated/immunology
Emerg Microbes Infect ; 9(1): 2653-2662, 2020 Dec.
Article in English | MEDLINE | ID: covidwho-977352


In the face of COVID-19 pandemic caused by the newly emerged SARS-CoV-2, an inactivated, Vero cell-based, whole virion vaccine candidate has been developed and entered into phase III clinical trials within six months. Biochemical and immunogenic characterization of structural proteins and their post-translational modifications in virions, the end-products of the vaccine candidate, would be essential for the quality control and process development of vaccine products and for studying the immunogenicity and pathogenesis of SARS-CoV-2. By using a panel of rabbit antisera against virions and five structural proteins together with a convalescent serum, the spike (S) glycoprotein was shown to be N-linked glycosylated, PNGase F-sensitive, endoglycosidase H-resistant and cleaved by Furin-like proteases into S1 and S2 subunits. The full-length S and S1/S2 subunits could form homodimers/trimers. The membrane (M) protein was partially N-linked glycosylated; the accessory protein 3a existed in three different forms, indicative of cleavage and dimerization. Furthermore, analysis of the antigenicity of these proteins and their post-translationally modified forms demonstrated that S protein induced the strongest antibody response in both convalescent and immunized animal sera. Interestingly, immunization with the inactivated vaccine did not elicit antibody response against the S2 subunit, whereas strong antibody response against both S1 and S2 subunits was detected in the convalescent serum. Moreover, vaccination stimulated stronger antibody response against S multimers than did the natural infection. This study revealed that the native S glycoprotein stimulated neutralizing antibodies, while bacterially-expressed S fragments did not. The study on S modifications would facilitate design of S-based anti-SARS-CoV-2 vaccines.

COVID-19 Vaccines , Protein Processing, Post-Translational , SARS-CoV-2/isolation & purification , Viral Structural Proteins , Virion , Animals , Antigens, Viral/analysis , Antigens, Viral/metabolism , COVID-19 Vaccines/chemistry , COVID-19 Vaccines/immunology , Cattle , Chlorocebus aethiops , Humans , Rabbits , SARS-CoV-2/immunology , Vaccines, Inactivated/chemistry , Vaccines, Inactivated/immunology , Vero Cells , Viral Structural Proteins/chemistry , Viral Structural Proteins/immunology , Viral Structural Proteins/isolation & purification , Virion/chemistry , Virion/immunology , Virion/isolation & purification
Emerg Microbes Infect ; 9(1): 2606-2618, 2020 Dec.
Article in English | MEDLINE | ID: covidwho-944152


The ongoing COVID-19 pandemic is causing huge impact on health, life, and global economy, which is characterized by rapid spreading of SARS-CoV-2, high number of confirmed cases and a fatality/case rate worldwide reported by WHO. The most effective intervention measure will be to develop safe and effective vaccines to protect the population from the disease and limit the spread of the virus. An inactivated, whole virus vaccine candidate of SARS-CoV-2 has been developed by Wuhan Institute of Biological Products and Wuhan Institute of Virology. The low toxicity, immunogenicity, and immune persistence were investigated in preclinical studies using seven different species of animals. The results showed that the vaccine candidate was well tolerated and stimulated high levels of specific IgG and neutralizing antibodies. Low or no toxicity in three species of animals was also demonstrated in preclinical study of the vaccine candidate. Biochemical analysis of structural proteins and purity analysis were performed. The inactivated, whole virion vaccine was characterized with safe double-inactivation, no use of DNases and high purity. Dosages, boosting times, adjuvants, and immunization schedules were shown to be important for stimulating a strong humoral immune response in animals tested. Preliminary observation in ongoing phase I and II clinical trials of the vaccine candidate in Wuzhi County, Henan Province, showed that the vaccine is well tolerant. The results were characterized by very low proportion and low degree of side effects, high levels of neutralizing antibodies, and seroconversion. These results consistent with the results obtained from preclinical data on the safety.

COVID-19 Vaccines/immunology , SARS-CoV-2 , Animals , Antibodies, Viral , COVID-19 Vaccines/adverse effects , Female , Immunity, Humoral , Male , Vaccines, Inactivated/adverse effects , Vaccines, Inactivated/immunology
Cell Res ; 30(8): 670-677, 2020 08.
Article in English | MEDLINE | ID: covidwho-637104


The 2019 novel coronavirus (SARS-CoV-2) outbreak is a major challenge for public health. SARS-CoV-2 infection in human has a broad clinical spectrum ranging from mild to severe cases, with a mortality rate of ~6.4% worldwide (based on World Health Organization daily situation report). However, the dynamics of viral infection, replication and shedding are poorly understood. Here, we show that Rhesus macaques are susceptible to the infection by SARS-CoV-2. After intratracheal inoculation, the first peak of viral RNA was observed in oropharyngeal swabs one day post infection (1 d.p.i.), mainly from the input of the inoculation, while the second peak occurred at 5 d.p.i., which reflected on-site replication in the respiratory tract. Histopathological observation shows that SARS-CoV-2 infection can cause interstitial pneumonia in animals, characterized by hyperemia and edema, and infiltration of monocytes and lymphocytes in alveoli. We also identified SARS-CoV-2 RNA in respiratory tract tissues, including trachea, bronchus and lung; and viruses were also re-isolated from oropharyngeal swabs, bronchus and lung, respectively. Furthermore, we demonstrated that neutralizing antibodies generated from the primary infection could protect the Rhesus macaques from a second-round challenge by SARS-CoV-2. The non-human primate model that we established here provides a valuable platform to study SARS-CoV-2 pathogenesis and to evaluate candidate vaccines and therapeutics.

Betacoronavirus/genetics , Betacoronavirus/immunology , Coronavirus Infections/pathology , Disease Models, Animal , Macaca mulatta/virology , Pneumonia, Viral/pathology , Animals , Antibodies, Neutralizing/blood , Antibodies, Neutralizing/immunology , Antibodies, Viral/blood , Antibodies, Viral/immunology , Betacoronavirus/isolation & purification , COVID-19 , Coronavirus Infections/blood , Coronavirus Infections/diagnostic imaging , Coronavirus Infections/virology , Female , Immunohistochemistry , Male , Pandemics , Pneumonia, Viral/blood , Pneumonia, Viral/diagnostic imaging , Pneumonia, Viral/virology , RNA, Viral/genetics , Radiography, Thoracic , Real-Time Polymerase Chain Reaction , SARS-CoV-2 , Viral Load , Virus Replication
Emerg Microbes Infect ; 9(1): 1170-1173, 2020 Dec.
Article in English | MEDLINE | ID: covidwho-324574


The emerging SARS-CoV-2 infection associated with the outbreak of viral pneumonia in China is ongoing worldwide. There are no approved antiviral therapies to treat this viral disease. Here we examined the antiviral abilities of three broad-spectrum antiviral compounds gemcitabine, lycorine and oxysophoridine against SARS-CoV-2 in cell culture. We found that all three tested compounds inhibited viral replication in Vero-E6 cells at noncytotoxic concentrations. The antiviral effect of gemcitabine was suppressed efficiently by the cytidine nucleosides. Additionally, combination of gemcitabine with oxysophoridine had an additive antiviral effect against SARS-CoV-2. Our results demonstrate that broad-spectrum antiviral compounds may have a priority for the screening of antiviral compounds against newly emerging viruses to control viral infection.

Alkaloids/pharmacology , Amaryllidaceae Alkaloids/pharmacology , Antiviral Agents/pharmacology , Betacoronavirus/drug effects , Deoxycytidine/analogs & derivatives , Phenanthridines/pharmacology , Virus Replication/drug effects , Animals , Betacoronavirus/growth & development , Betacoronavirus/metabolism , Cell Survival/drug effects , Chlorocebus aethiops , Chloroquine/pharmacology , Deoxycytidine/pharmacology , Dose-Response Relationship, Drug , Drug Combinations , Drug Synergism , SARS-CoV-2 , Vero Cells