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1.
Vaccine ; 40(14): 2233-2239, 2022 03 25.
Article in English | MEDLINE | ID: covidwho-1757910

ABSTRACT

A reference standard is needed for quality control of protein subunit SARS-CoV-2 vaccines to meet urgent domestic needs. The Chinese National Institutes for Food and Drug Control (NIFDC) launched a project to establish the first reference material for the protein subunit SARS-CoV-2 vaccine to be used for calibration of antigen testing. The potency and stability of the national candidate standard (CS) were determined by collaborative calibration, and accelerated and freeze-thaw degradation studies. Moreover, a suitability study of the CS was performed. Eight laboratories in mainland China were asked to detect antigen content of CS using a common validated enzyme-linked immunosorbent assay (ELISA) kit established by NIFDC and in-house kits in the collaborative study. Six laboratories returned valid results, which established that the antigen content of the CS was 876,938 YU/mL, with good agreement across laboratories. In the suitability study, the CS exhibited excellent parallelism and a linear relationship with four samples produced by different expression systems and target proteins. In addition, good stability in the accelerated and freeze-thaw degradation study was observed. In conclusion, the CS was approved by the Biological Product Reference Standards Sub-Committee of the National Drug Reference Standards Committee as the first Chinese national standard for determining antigen content of protein subunit SARS-CoV-2 vaccines, with an assigned antigen content of 877,000 U/mL (Lot. 300050-202101). This standard will contribute to a standardized assessment of protein subunit SARS-CoV-2 vaccine in China and may provide experience for developing reference materials for antigen content detection of SARS-CoV-2 vaccine in other countries.


Subject(s)
COVID-19 Vaccines , COVID-19 , COVID-19/prevention & control , Humans , Protein Subunits , Reference Standards , SARS-CoV-2
2.
Mol Ther Methods Clin Dev ; 23: 108-118, 2021 Dec 10.
Article in English | MEDLINE | ID: covidwho-1379195

ABSTRACT

Because of the relatively limited understanding of coronavirus disease 2019 (COVID-19) pathogenesis, immunological analysis for vaccine development is needed. Mice and macaques were immunized with an inactivated severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine prepared by two inactivators. Various immunological indexes were tested, and viral challenges were performed on day 7 or 150 after booster immunization in monkeys. This inactivated SARS-CoV-2 vaccine was produced by sequential inactivation with formaldehyde followed by propiolactone. The various antibody responses and specific T cell responses to different viral antigens elicited in immunized animals were maintained for longer than 150 days. This comprehensive immune response could effectively protect vaccinated macaques by inhibiting viral replication in macaques and substantially alleviating immunopathological damage, and no clinical manifestation of immunopathogenicity was observed in immunized individuals during viral challenge. This candidate inactivated vaccine was identified as being effective against SARS-CoV-2 challenge in rhesus macaques.

3.
Emerg Microbes Infect ; 10(1): 1519-1529, 2021 Dec.
Article in English | MEDLINE | ID: covidwho-1316787

ABSTRACT

The spike (S) protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mutated continuously and newly emerging variants escape from antibody-mediated neutralization raised great concern. S protein is heavily glycosylated and the glycosylation sites are relatively conserved, thus glycans on S protein surface could be a target for the development of anti-SARS-CoV-2 strategies against variants. Here, we collected 12 plant-derived lectins with different carbohydrate specificity and evaluated their anti-SARS-CoV-2 activity against mutant strains and epidemic variants using a pseudovirus-based neutralization assay. The Lens culinaris-derived lentil lectin which specifically bind to oligomannose-type glycans and GlcNAc at the non-reducing end terminus showed most potent and broad antiviral activity against a panel of mutant strains and variants, including the artificial mutants at N-/O-linked glycosylation site, natural existed amino acid mutants, as well as the epidemic variants B.1.1.7, B.1.351, and P.1. Lentil lectin also showed antiviral activity against SARS-CoV and MERS-CoV. We found lentil lectin could block the binding of ACE2 to S trimer and inhibit SARS-CoV-2 at the early steps of infection. Using structural information and determined N-glycan profile of S trimer, taking together with the carbohydrate specificity of lentil lectin, we provide a basis for the observed broad spectrum anti-SARS-CoV-2 activity. Lentil lectin showed weak haemagglutination activity at 1 mg/mL and no cytotoxicity activity, and no weight loss was found in single injection mouse experiment. This report provides the first evidence that lentil lectin strongly inhibit infection of SARS-COV-2 variants, which should provide valuable insights for developing future anti-SARS-CoV-2 strategies.


Subject(s)
Antiviral Agents/pharmacology , Lens Plant/chemistry , Plant Extracts/pharmacology , Plant Lectins/pharmacology , SARS-CoV-2/drug effects , Animals , Antiviral Agents/chemistry , Humans , Mice , Mice, Inbred BALB C , Plant Extracts/chemistry , Plant Lectins/chemistry , SARS-CoV-2/growth & development , Seeds/chemistry
4.
Emerg Microbes Infect ; 9(1): 2606-2618, 2020 Dec.
Article in English | MEDLINE | ID: covidwho-944152

ABSTRACT

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.


Subject(s)
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
5.
Science ; 369(6499): 77-81, 2020 07 03.
Article in English | MEDLINE | ID: covidwho-667322

ABSTRACT

The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has resulted in an unprecedented public health crisis. Because of the novelty of the virus, there are currently no SARS-CoV-2-specific treatments or vaccines available. Therefore, rapid development of effective vaccines against SARS-CoV-2 are urgently needed. Here, we developed a pilot-scale production of PiCoVacc, a purified inactivated SARS-CoV-2 virus vaccine candidate, which induced SARS-CoV-2-specific neutralizing antibodies in mice, rats, and nonhuman primates. These antibodies neutralized 10 representative SARS-CoV-2 strains, suggesting a possible broader neutralizing ability against other strains. Three immunizations using two different doses, 3 or 6 micrograms per dose, provided partial or complete protection in macaques against SARS-CoV-2 challenge, respectively, without observable antibody-dependent enhancement of infection. These data support the clinical development and testing of PiCoVacc for use in humans.


Subject(s)
Antibodies, Neutralizing/blood , Antibodies, Viral/blood , Betacoronavirus/immunology , Coronavirus Infections/prevention & control , Pandemics/prevention & control , Pneumonia, Viral/prevention & control , Viral Vaccines , Animals , Antibodies, Neutralizing/biosynthesis , Antibodies, Neutralizing/immunology , Antibodies, Viral/biosynthesis , Antibodies, Viral/immunology , Betacoronavirus/isolation & purification , COVID-19 , COVID-19 Vaccines , Chlorocebus aethiops , Coronavirus Infections/immunology , Coronavirus Infections/virology , Dose-Response Relationship, Immunologic , Female , Immunogenicity, Vaccine , Immunoglobulin G/biosynthesis , Immunoglobulin G/blood , Immunoglobulin G/immunology , Macaca mulatta , Male , Mice , Mice, Inbred BALB C , Pilot Projects , Pneumonia, Viral/virology , Rats , Rats, Wistar , SARS-CoV-2 , Vaccines, Inactivated/administration & dosage , Vaccines, Inactivated/adverse effects , Vaccines, Inactivated/immunology , Vero Cells , Viral Load , Viral Vaccines/administration & dosage , Viral Vaccines/adverse effects , Viral Vaccines/immunology
6.
Science ; 369(6499): 77-81, 2020 07 03.
Article in English | MEDLINE | ID: covidwho-197649

ABSTRACT

The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has resulted in an unprecedented public health crisis. Because of the novelty of the virus, there are currently no SARS-CoV-2-specific treatments or vaccines available. Therefore, rapid development of effective vaccines against SARS-CoV-2 are urgently needed. Here, we developed a pilot-scale production of PiCoVacc, a purified inactivated SARS-CoV-2 virus vaccine candidate, which induced SARS-CoV-2-specific neutralizing antibodies in mice, rats, and nonhuman primates. These antibodies neutralized 10 representative SARS-CoV-2 strains, suggesting a possible broader neutralizing ability against other strains. Three immunizations using two different doses, 3 or 6 micrograms per dose, provided partial or complete protection in macaques against SARS-CoV-2 challenge, respectively, without observable antibody-dependent enhancement of infection. These data support the clinical development and testing of PiCoVacc for use in humans.


Subject(s)
Antibodies, Neutralizing/blood , Antibodies, Viral/blood , Betacoronavirus/immunology , Coronavirus Infections/prevention & control , Pandemics/prevention & control , Pneumonia, Viral/prevention & control , Viral Vaccines , Animals , Antibodies, Neutralizing/biosynthesis , Antibodies, Neutralizing/immunology , Antibodies, Viral/biosynthesis , Antibodies, Viral/immunology , Betacoronavirus/isolation & purification , COVID-19 , COVID-19 Vaccines , Chlorocebus aethiops , Coronavirus Infections/immunology , Coronavirus Infections/virology , Dose-Response Relationship, Immunologic , Female , Immunogenicity, Vaccine , Immunoglobulin G/biosynthesis , Immunoglobulin G/blood , Immunoglobulin G/immunology , Macaca mulatta , Male , Mice , Mice, Inbred BALB C , Pilot Projects , Pneumonia, Viral/virology , Rats , Rats, Wistar , SARS-CoV-2 , Vaccines, Inactivated/administration & dosage , Vaccines, Inactivated/adverse effects , Vaccines, Inactivated/immunology , Vero Cells , Viral Load , Viral Vaccines/administration & dosage , Viral Vaccines/adverse effects , Viral Vaccines/immunology
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