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1.
Vaccines (Basel) ; 11(5)2023 May 04.
Article in English | MEDLINE | ID: covidwho-20245130

ABSTRACT

Lipid nanoparticles (LNPs) are widely used as delivery systems for mRNA vaccines. The stability and bilayer fluidity of LNPs are determined by the properties and contents of the various lipids used in the formulation system, and the delivery efficiency of LNPs largely depends on the lipid composition. For the quality control of such vaccines, here we developed and validated an HPLC-CAD method to identify and determine the contents of four lipids in an LNP-encapsulated COVID-19 mRNA vaccine to support lipid analysis for the development of new drugs and vaccines.

2.
Journal of Agricultural Economics ; 74(2):369-393, 2023.
Article in English | ProQuest Central | ID: covidwho-2323416

ABSTRACT

COVID‐19 has caused major disruptions to agricultural supply chains around the world. Researchers and policy‐makers are interested in identifying means to reduce the disruptive effects caused by the pandemic. We investigate the impacts of COVID‐19 on the operation of e‐commerce stores (in short, e‐stores) specialising in agricultural inputs. The difference‐in‐differences method (DID) is employed to estimate the causal relationship between COVID‐19 and online sales of agricultural inputs using data from 54,244 agricultural input e‐stores registered in 118 prefecture‐level cities across 15 provinces and hosted on two major Chinese e‐commerce platforms. The results show that COVID‐19 led to a substantial growth in monthly sales of agricultural input e‐stores, and this growth of online sales varied across store scales and by types of agricultural inputs. In particular, e‐stores selling seeds and seedlings experienced a larger growth in sales than stores selling agricultural machinery and implements, and the mid‐ and larger‐scaled e‐stores experienced more growth of sales than micro‐ and small‐scaled e‐stores. Further analysis reveals that the growth of online sales of agricultural inputs was driven mainly by an increase in the quantity of customer orders (QCO). The findings of this paper underscore the importance of e‐commerce in ensuring the resilience of the agricultural supply chain during the pandemic period.

3.
Front Immunol ; 14: 1129118, 2023.
Article in English | MEDLINE | ID: covidwho-2298964

ABSTRACT

Chikungunya fever (CHIKF) has spread to more than 100 countries worldwide, with frequent outbreaks in Europe and the Americas in recent years. Despite the relatively low lethality of infection, patients can suffer from long-term sequelae. Until now, no available vaccines have been approved for use; however, increasing attention is being paid to the development of vaccines against chikungunya virus (CHIKV), and the World Health Organization has included vaccine development in the initial blueprint deliverables. Here, we developed an mRNA vaccine using the nucleotide sequence encoding structural proteins of CHIKV. And immunogenicity was evaluated by neutralization assay, Enzyme-linked immunospot assay and Intracellular cytokine staining. The results showed that the encoded proteins elicited high levels of neutralizing antibody titers and T cell-mediated cellular immune responses in mice. Moreover, compared with the wild-type vaccine, the codon-optimized vaccine elicited robust CD8+ T-cell responses and mild neutralizing antibody titers. In addition, higher levels of neutralizing antibody titers and T-cell immune responses were obtained using a homologous booster mRNA vaccine regimen of three different homologous or heterologous booster immunization strategies. Thus, this study provides assessment data to develop vaccine candidates and explore the effectiveness of the prime-boost approach.


Subject(s)
Chikungunya Fever , Chikungunya virus , Viral Vaccines , Animals , Mice , Chikungunya virus/genetics , Viral Vaccines/genetics , Antibodies, Viral , Antibodies, Neutralizing
4.
Front Immunol ; 14: 1142394, 2023.
Article in English | MEDLINE | ID: covidwho-2268865

ABSTRACT

The ongoing evolution of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2 or 2019-nCoV) variants has been associated with the transmission and pathogenicity of COVID-19. Therefore, exploring the optimal immunisation strategy to improve the broad-spectrum cross-protection ability of COVID-19 vaccines is of great significance. Herein, we assessed different heterologous prime-boost strategies with chimpanzee adenovirus vector-based COVID-19 vaccines plus Wuhan-Hu-1 (WH-1) strain (AdW) and Beta variant (AdB) and mRNA-based COVID-19 vaccines plus WH-1 strain (ARW) and Omicron (B.1.1.529) variant (ARO) in 6-week-old female BALB/c mice. AdW and AdB were administered intramuscularly or intranasally, while ARW and ARO were administered intramuscularly. Intranasal or intramuscular vaccination with AdB followed by ARO booster exhibited the highest levels of cross-reactive IgG, pseudovirus-neutralising antibody (PNAb) responses, and angiotensin-converting enzyme-2 (ACE2)-binding inhibition rates against different 2019-nCoV variants among all vaccination groups. Moreover, intranasal AdB vaccination followed by ARO induced higher levels of IgA and neutralising antibody responses against live 2019-nCoV than intramuscular AdB vaccination followed by ARO. A single dose of AdB administered intranasally or intramuscularly induced broader cross-NAb responses than AdW. Th1-biased cellular immune response was induced in all vaccination groups. Intramuscular vaccination-only groups exhibited higher levels of Th1 cytokines than intranasal vaccination-only and intranasal vaccination-containing groups. However, no obvious differences were found in the levels of Th2 cytokines between the control and all vaccination groups. Our findings provide a basis for exploring vaccination strategies against different 2019-nCoV variants to achieve high broad-spectrum immune efficacy.


Subject(s)
COVID-19 , Viral Vaccines , Female , Humans , Animals , Mice , COVID-19 Vaccines , SARS-CoV-2 , COVID-19/prevention & control , RNA, Messenger , Immunization , Vaccination , Antibodies, Neutralizing , Immunity, Cellular
5.
Mol Biomed ; 3(1): 40, 2022 Dec 08.
Article in English | MEDLINE | ID: covidwho-2153752

ABSTRACT

Vaccines are one of the most effective medical interventions to combat newly emerging and re-emerging diseases. Prophylactic vaccines against rabies, measles, etc., have excellent effectiveness in preventing viral infection and associated diseases. However, the host immune response is unable to inhibit virus replication or eradicate established diseases in most infected people. Therapeutic vaccines, expressing specific endogenous or exogenous antigens, mainly induce or boost cell-mediated immunity via provoking cytotoxic T cells or elicit humoral immunity via activating B cells to produce specific antibodies. The ultimate aim of a therapeutic vaccine is to reshape the host immunity for eradicating a disease and establishing lasting memory. Therefore, therapeutic vaccines have been developed for the treatment of some infectious diseases and chronic noncommunicable diseases. Various technological strategies have been implemented for the development of therapeutic vaccines, including molecular-based vaccines (peptide/protein, DNA and mRNA vaccines), vector-based vaccines (bacterial vector vaccines, viral vector vaccines and yeast-based vaccines) and cell-based vaccines (dendritic cell vaccines and genetically modified cell vaccines) as well as combinatorial approaches. This review mainly summarizes therapeutic vaccine-induced immunity and describes the development and status of multiple types of therapeutic vaccines against infectious diseases, such as those caused by HPV, HBV, HIV, HCV, and SARS-CoV-2, and chronic noncommunicable diseases, including cancer, hypertension, Alzheimer's disease, amyotrophic lateral sclerosis, diabetes, and dyslipidemia, that have been evaluated in recent preclinical and clinical studies.

6.
Frontiers in immunology ; 13, 2022.
Article in English | EuropePMC | ID: covidwho-2125393

ABSTRACT

Development of safe and efficient vaccines is still necessary to deal with the COVID-19 pandemic. Herein, we reported that yeast-expressed recombinant RBD proteins either from wild-type or Delta SARS-CoV-2 were able to elicit immune responses against SARS-CoV-2 and its variants. The wild-type RBD (wtRBD) protein was overexpressed in Pichia pastoris, and the purified protein was used as the antigen to immunize mice after formulating an aluminium hydroxide (Alum) adjuvant. Three immunization programs with different intervals were compared. It was found that the immunization with an interval of 28 days exhibited the strongest immune response to SARS-CoV-2 than the one with an interval of 14 or 42 days based on binding antibody and the neutralizing antibody (NAb) analyses. The antisera from the mice immunized with wtRBD were able to neutralize the Beta variant with a similar efficiency but the Delta variant with 2~2.5-fold decreased efficiency. However, more NAbs to the Delta variant were produced when the Delta RBD protein was used to immunize mice. Interestingly, the NAbs may cross react with the Omicron variant. To increase the production of NAbs, the adjuvant combination of Alum and CpG oligonucleotides was used. Compared with the Alum adjuvant alone, the NAbs elicited by the combined adjuvants exhibited an approximate 10-fold increase for the Delta and a more than 53-fold increase for the Omicron variant. This study suggested that yeast-derived Delta RBD is a scalable and an effective vaccine candidate for SARS-CoV-2 and its variants.

7.
Journal of Agricultural Economics ; 2022.
Article in English | Web of Science | ID: covidwho-2082376

ABSTRACT

COVID-19 has caused major disruptions to agricultural supply chains around the world. Researchers and policy-makers are interested in identifying means to reduce the disruptive effects caused by the pandemic. We investigate the impacts of COVID-19 on the operation of e-commerce stores (in short, e-stores) specialising in agricultural inputs. The difference-in-differences method (DID) is employed to estimate the causal relationship between COVID-19 and online sales of agricultural inputs using data from 54,244 agricultural input e-stores registered in 118 prefecture-level cities across 15 provinces and hosted on two major Chinese e-commerce platforms. The results show that COVID-19 led to a substantial growth in monthly sales of agricultural input e-stores, and this growth of online sales varied across store scales and by types of agricultural inputs. In particular, e-stores selling seeds and seedlings experienced a larger growth in sales than stores selling agricultural machinery and implements, and the mid- and larger-scaled e-stores experienced more growth of sales than micro- and small-scaled e-stores. Further analysis reveals that the growth of online sales of agricultural inputs was driven mainly by an increase in the quantity of customer orders (QCO). The findings of this paper underscore the importance of e-commerce in ensuring the resilience of the agricultural supply chain during the pandemic period.

8.
Journal of Agricultural Economics ; : 1, 2022.
Article in English | Academic Search Complete | ID: covidwho-2078276

ABSTRACT

COVID‐19 has caused major disruptions to agricultural supply chains around the world. Researchers and policy‐makers are interested in identifying means to reduce the disruptive effects caused by the pandemic. We investigate the impacts of COVID‐19 on the operation of e‐commerce stores (in short, e‐stores) specialising in agricultural inputs. The difference‐in‐differences method (DID) is employed to estimate the causal relationship between COVID‐19 and online sales of agricultural inputs using data from 54,244 agricultural input e‐stores registered in 118 prefecture‐level cities across 15 provinces and hosted on two major Chinese e‐commerce platforms. The results show that COVID‐19 led to a substantial growth in monthly sales of agricultural input e‐stores, and this growth of online sales varied across store scales and by types of agricultural inputs. In particular, e‐stores selling seeds and seedlings experienced a larger growth in sales than stores selling agricultural machinery and implements, and the mid‐ and larger‐scaled e‐stores experienced more growth of sales than micro‐ and small‐scaled e‐stores. Further analysis reveals that the growth of online sales of agricultural inputs was driven mainly by an increase in the quantity of customer orders (QCO). The findings of this paper underscore the importance of e‐commerce in ensuring the resilience of the agricultural supply chain during the pandemic period. [ FROM AUTHOR]

9.
Hum Vaccin Immunother ; : 2094142, 2022 Jul 11.
Article in English | MEDLINE | ID: covidwho-1927246

ABSTRACT

ARCoV is a candidate mRNA vaccine encoding receptor-binding domain of SARS-CoV-2. Its safety, tolerability, and immunogenicity profile have been confirmed in the phase 1 clinical trial in China. A multi-regional phase 3 clinical trial is currently underway to test the efficacy of ARCoV (NCT04847102). Here, we tested the cross-neutralization against SARS-CoV-2 variants of concern (VOCs) of a panel of serum samples from participants in the phase 1 clinical trial of ARCoV by pesudo- and authentic SARS-CoV-2. Our data suggest the immunity induced by the ARCoV vaccine reduced but still has significant neutralization against the Alpha and Delta variants. Moreover, ARCoV maintained activity against the Beta variant, despite of its obvious reduction in neutralizing titers. Our findings further support the solid protective neutralization activity against VOCs induced by ARCoV vaccine.

10.
Emerg Microbes Infect ; 11(1): 1890-1899, 2022 Dec.
Article in English | MEDLINE | ID: covidwho-1915484

ABSTRACT

The efficacy of many coronavirus disease 2019 (COVID-19) vaccines has been shown to decrease to varying extents against new severe acute respiratory syndrome coronavirus 2 variants, which are responsible for the continuing COVID-19 pandemic. Combining intramuscular and intranasal vaccination routes is a promising approach for achieving more potent immune responses. We evaluated the immunogenicity of prime-boost protocols with a chimpanzee adenovirus serotype 68 vector-based vaccine, ChAdTS-S, administered via both intranasal and intramuscular routes in BALB/c mice. Intramuscular priming followed by an intranasal booster elicited the highest levels of IgG, IgA, and pseudovirus neutralizing antibody titres among all the protocols tested at day 42 after prime immunization compared with the intranasal priming/intramuscular booster and prime-boost protocols using only one route. In addition, intramuscular priming followed by an intranasal booster induced high T-cell responses, measured using the IFN-γ ELISpot assay, that were similar to those observed upon intramuscular vaccination. All ChAdTS-S vaccination groups induced Th1-skewing of the T-cell response according to intracellular cytokine staining and Meso Scale Discovery cytokine profiling assays on day 56 after priming. This study provides reference data for assessing vaccination schemes of adenovirus-based COVID-19 vaccines with high immune efficacy.


Subject(s)
COVID-19 Vaccines , COVID-19 , Adenoviridae/genetics , Animals , Antibodies, Neutralizing , Antibodies, Viral , COVID-19/prevention & control , COVID-19 Vaccines/immunology , Cytokines , Immunity, Cellular , Immunity, Humoral , Immunization, Secondary , Mice , Mice, Inbred BALB C , Pan troglodytes , SARS-CoV-2 , Vaccination
12.
Signal Transduct Target Ther ; 7(1): 94, 2022 03 23.
Article in English | MEDLINE | ID: covidwho-1758181

ABSTRACT

To date, the coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has determined 399,600,607 cases and 5,757,562 deaths worldwide. COVID-19 is a serious threat to human health globally. The World Health Organization (WHO) has declared COVID-19 pandemic a major public health emergency. Vaccination is the most effective and economical intervention for controlling the spread of epidemics, and consequently saving lives and protecting the health of the population. Various techniques have been employed in the development of COVID-19 vaccines. Among these, the COVID-19 messenger RNA (mRNA) vaccine has been drawing increasing attention owing to its great application prospects and advantages, which include short development cycle, easy industrialization, simple production process, flexibility to respond to new variants, and the capacity to induce better immune response. This review summarizes current knowledge on the structural characteristics, antigen design strategies, delivery systems, industrialization potential, quality control, latest clinical trials and real-world data of COVID-19 mRNA vaccines as well as mRNA technology. Current challenges and future directions in the development of preventive mRNA vaccines for major infectious diseases are also discussed.


Subject(s)
COVID-19 Vaccines , COVID-19 , COVID-19/prevention & control , COVID-19 Vaccines/genetics , Humans , Pandemics/prevention & control , RNA, Messenger/genetics , SARS-CoV-2/genetics , Vaccines, Synthetic , mRNA Vaccines
13.
Front Cell Infect Microbiol ; 12: 802147, 2022.
Article in English | MEDLINE | ID: covidwho-1753359

ABSTRACT

Owing to the outbreak of the novel coronavirus (SARS-CoV-2) worldwide at the end of 2019, the development of a SARS-CoV-2 vaccine became an urgent need. In this study, we developed a type 9 adeno-associated virus vectored vaccine candidate expressing a dimeric receptor binding domain (RBD) of the SARS-CoV-2 spike protein (S protein) and evaluated its immunogenicity in a murine model. The vaccine candidate, named AAV9-RBD virus, was constructed by inserting a signal peptide to the N-terminus of two copies of RBD, spaced by a linker, into the genome of a type 9 adeno-associated virus. In vitro assays showed that HeLa cells infected by the recombinant AAV virus expressed high levels of the recombinant RBD protein, mostly found in the cell culture supernatant. The recombinant AAV9-RBD virus was cultured and purified. The genome titer of the purified recombinant AAV9-RBD virus was determined to be 2.4 × 1013 genome copies/mL (GC/mL) by Q-PCR. Balb/c mice were immunized with the virus by intramuscular injection or nasal drip administration. Eight weeks after immunization, neutralizing antibodies against the new coronavirus pseudovirus were detected in the sera of all mice; the mean neutralizing antibody EC50 values were 517.7 ± 292.1 (n=10) and 682.8 ± 454.0 (n=10) in the intramuscular injection group and nasal drip group, respectively. The results of this study showed that the recombinant AAV9-RBD virus may be used for the development of a SARS-CoV-2 vaccine.


Subject(s)
COVID-19 Vaccines , COVID-19 , Animals , COVID-19/prevention & control , Dependovirus/genetics , HeLa Cells , Humans , Mice , Mice, Inbred BALB C , SARS-CoV-2/genetics , Spike Glycoprotein, Coronavirus
14.
Journal of Medical Virology ; 94(5):i-i, 2022.
Article in English | Wiley | ID: covidwho-1750403

ABSTRACT

Front Cover Caption: The cover image is based on the Research Article Aggregation of high-frequency RBD mutations of SARS-CoV-2 with three VOCs did not cause significant antigenic drift by Tao Li et al., https://doi.org/10.1002/jmv.27596.

15.
Lancet Microbe ; 3(3): e193-e202, 2022 Mar.
Article in English | MEDLINE | ID: covidwho-1721237

ABSTRACT

BACKGROUND: Safe and effective vaccines are urgently needed to end the COVID-19 pandemic caused by SARS-CoV-2 infection. We aimed to assess the preliminary safety, tolerability, and immunogenicity of an mRNA vaccine ARCoV, which encodes the SARS-CoV-2 spike protein receptor-binding domain (RBD). METHODS: This single centre, double-blind, randomised, placebo-controlled, dose-escalation, phase 1 trial of ARCoV was conducted at Shulan (Hangzhou) hospital in Hangzhou, Zhejiang province, China. Healthy adults aged 18-59 years negative for SARS-CoV-2 infection were enrolled and randomly assigned using block randomisation to receive an intramuscular injection of vaccine or placebo. Vaccine doses were 5 µg, 10 µg, 15 µg, 20 µg, and 25 µg. The first six participants in each block were sentinels and along with the remaining 18 participants, were randomly assigned to groups (5:1). In block 1 sentinels were given the lowest vaccine dose and after a 4-day observation with confirmed safety analyses, the remaining 18 participants in the same dose group proceeded and sentinels in block 2 were given their first administration on a two-dose schedule, 28 days apart. All participants, investigators, and staff doing laboratory analyses were masked to treatment allocation. Humoral responses were assessed by measuring anti-SARS-CoV-2 RBD IgG using a standardised ELISA and neutralising antibodies using pseudovirus-based and live SARS-CoV-2 neutralisation assays. SARS-CoV-2 RBD-specific T-cell responses, including IFN-γ and IL-2 production, were assessed using an enzyme-linked immunospot (ELISpot) assay. The primary outcome for safety was incidence of adverse events or adverse reactions within 60 min, and at days 7, 14, and 28 after each vaccine dose. The secondary safety outcome was abnormal changes detected by laboratory tests at days 1, 4, 7, and 28 after each vaccine dose. For immunogenicity, the secondary outcome was humoral immune responses: titres of neutralising antibodies to live SARS-CoV-2, neutralising antibodies to pseudovirus, and RBD-specific IgG at baseline and 28 days after first vaccination and at days 7, 15, and 28 after second vaccination. The exploratory outcome was SARS-CoV-2-specific T-cell responses at 7 days after the first vaccination and at days 7 and 15 after the second vaccination. This trial is registered with www.chictr.org.cn (ChiCTR2000039212). FINDINGS: Between Oct 30 and Dec 2, 2020, 230 individuals were screened and 120 eligible participants were randomly assigned to receive five-dose levels of ARCoV or a placebo (20 per group). All participants received the first vaccination and 118 received the second dose. No serious adverse events were reported within 56 days after vaccination and the majority of adverse events were mild or moderate. Fever was the most common systemic adverse reaction (one [5%] of 20 in the 5 µg group, 13 [65%] of 20 in the 10 µg group, 17 [85%] of 20 in the 15 µg group, 19 [95%] of 20 in the 20 µg group, 16 [100%] of 16 in the 25 µg group; p<0·0001). The incidence of grade 3 systemic adverse events were none (0%) of 20 in the 5 µg group, three (15%) of 20 in the 10 µg group, six (30%) of 20 in the 15 µg group, seven (35%) of 20 in the 20 µg group, five (31%) of 16 in the 25 µg group, and none (0%) of 20 in the placebo group (p=0·0013). As expected, the majority of fever resolved in the first 2 days after vaccination for all groups. The incidence of solicited systemic adverse events was similar after administration of ARCoV as a first or second vaccination. Humoral immune responses including anti-RBD IgG and neutralising antibodies increased significantly 7 days after the second dose and peaked between 14 and 28 days thereafter. Specific T-cell response peaked between 7 and 14 days after full vaccination. 15 µg induced the highest titre of neutralising antibodies, which was about twofold more than the antibody titre of convalescent patients with COVID-19. INTERPRETATION: ARCoV was safe and well tolerated at all five doses. The acceptable safety profile, together with the induction of strong humoral and cellular immune responses, support further clinical testing of ARCoV at a large scale. FUNDING: National Key Research and Development Project of China, Academy of Medical Sciences China, National Natural Science Foundation China, and Chinese Academy of Medical Sciences.


Subject(s)
COVID-19 , SARS-CoV-2 , Adult , Antibodies, Neutralizing , Antibodies, Viral , COVID-19/prevention & control , COVID-19 Vaccines/adverse effects , China , Humans , Immunogenicity, Vaccine , Immunoglobulin G , Pandemics/prevention & control , Spike Glycoprotein, Coronavirus , Vaccines, Synthetic , mRNA Vaccines
16.
Eur J Med Chem ; 234: 114209, 2022 Apr 15.
Article in English | MEDLINE | ID: covidwho-1719653

ABSTRACT

Thirty-two clofazimine derivatives, of which twenty-two were new, were synthesized and evaluated for their antiviral effects against both rabies virus and pseudo-typed SARS-CoV-2, taking clofazimine (1) as the lead. Among them, compound 15f bearing 4-methoxy-2-pyridyl at the N5-position showed superior or comparable antiviral activities to lead 1, with the EC50 values of 1.45 µM and 14.6 µM and the SI values of 223 and 6.1, respectively. Compound 15f inhibited rabies and SARS-CoV-2 by targeting G or S protein to block membrane fusion, as well as binding to L protein or nsp13 to inhibit intracellular biosynthesis respectively, and thus synergistically exerted a broad-spectrum antiviral effect. The results provided useful scientific data for the development of clofazimine derivatives into a new class of broad-spectrum antiviral candidates.


Subject(s)
Antiviral Agents , COVID-19 , Antiviral Agents/chemistry , Antiviral Agents/pharmacology , Clofazimine , Humans , SARS-CoV-2
17.
Front Public Health ; 9: 794359, 2021.
Article in English | MEDLINE | ID: covidwho-1686570

ABSTRACT

Objectives: This study aimed to explore the utilization of a mobile multifunctional workstation for COVID-19 sample collection. Methods: Twenty-four nurses and 150 individuals who took nucleic acid tests using mobile multifunctional workstations in Beijing Youan Hospital, Capital Medical University, from September to November 2020, were enrolled in the study as the observation group. As the control group, we included 36 nurses and 150 individuals who did not use the workstations from June to September 2020. We compared the two groups on (1) comfort of working environment, self-perceived security, the convenience of information system, operational process flexibility, pharyngeal acquisition visibility, and effectiveness of communication among nurses; and (2) self-perceived safety, waiting time, and overall satisfaction among individuals who took nucleic acid tests. Results: The satisfaction score of nurses in the observation group of nurses were significantly higher than those of the control group (OR = 17.297 95% CI:4.294, 69.673), as well as the convenience of the information system (OR = 6.250 95% CI: 1.775, 22.008), and communication effectiveness (OR = 5.588 95% CI: 1.590, 19.646). Among individuals who took nucleic acid tests, the overall satisfaction (P < 0.05) and self-perceived security (P < 0.05) had statistical differences between the observation group and the control group. Conclusions: The mobile multifunctional workstation for specimen collection could improve the comfort of the working environment, the convenience of information systems, and the effectiveness of communication among nurses.It can improve satisfaction and self-perceived security among people who took nucleic acid tests.


Subject(s)
COVID-19 , Humans , Personal Satisfaction , SARS-CoV-2 , Specimen Handling , Workplace
18.
J Med Virol ; 94(5): 2108-2125, 2022 05.
Article in English | MEDLINE | ID: covidwho-1627779

ABSTRACT

Variants of SARS-CoV-2 continue to emerge, posing great challenges in outbreak prevention and control. It is important to understand in advance the impact of possible variants of concern (VOCs) on infectivity and antigenicity. Here, we constructed one or more of the 15 high-frequency naturally occurring amino acid changes in the receptor-binding domain (RBD) of Alpha, Beta, and Gamma variants. A single mutant of A520S, V367F, and S494P in the above three VOCs enhanced infectivity in ACE2-overexpressing 293T cells of different species, LLC-MK2 and Vero cells. Aggregation of multiple RBD mutations significantly reduces the infectivity of the possible three VOCs. Regarding neutralization, it is noteworthy that E484K, N501Y, K417N, and N439K predispose to monoclonal antibodies (mAbs) protection failure in the 15 high-frequency mutations. Most importantly, almost all possible VOCs (single RBD mutation or aggregation of multiple mutations) showed no more than a fourfold decrease in neutralizing activity with convalescent sera, vaccine sera, and immune sera of guinea pigs with different immunogens, and no significant antigenic drift was formed. In conclusion, our pseudovirus results could reduce the concern that the aggregation of multiple high-frequency mutations in the RBD of the spike protein of the three VOCs would lead to severe antigenic drift, and this would provide value for vaccine development strategies.


Subject(s)
COVID-19 , SARS-CoV-2 , Animals , Antibodies, Neutralizing , Antigenic Drift and Shift , COVID-19/therapy , Chlorocebus aethiops , Guinea Pigs , Humans , Immunization, Passive , Mutation , SARS-CoV-2/genetics , Spike Glycoprotein, Coronavirus , Vero Cells , COVID-19 Serotherapy
20.
Emerg Microbes Infect ; 11(1): 18-29, 2022 Dec.
Article in English | MEDLINE | ID: covidwho-1532383

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 variants have continued to emerge in diverse geographic locations with a temporal distribution. The Lambda variant containing multiple mutations in the spike protein, has thus far appeared mainly in South America. The variant harbours two mutations in the receptor binding domain, L452Q and F490S, which may change its infectivity and antigenicity to neutralizing antibodies. In this study, we constructed 10 pseudoviruses to study the Lambda variant and each individual amino acid mutation's effect on viral function, and used eight cell lines to study variant infectivity. In total, 12 monoclonal antibodies, 14 convalescent sera, and 23 immunized sera induced by mRNA vaccines, inactivated vaccine, and adenovirus type 5 vector vaccine were used to study the antigenicity of the Lambda variant. We found that compared with the D614G reference strain, Lambda demonstrated enhanced infectivity of Calu-3 and LLC-MK2 cells by 3.3-fold and 1.6-fold, respectively. Notably, the sensitivity of the Lambda variant to 5 of 12 neutralizing monoclonal antibodies, 9G11, AM180, R126, X593, and AbG3, was substantially diminished. Furthermore, convalescent- and vaccine-immunized sera showed on average 1.3-2.5-fold lower neutralizing titres against the Lambda variant. Single mutation analysis revealed that this reduction in neutralization was caused by L452Q and F490S mutations. Collectively, the reduced neutralization ability of the Lambda variant suggests that the efficacy of monoclonal antibodies and vaccines may be compromised during the current pandemic.


Subject(s)
Antibodies, Monoclonal/immunology , Antibodies, Neutralizing/immunology , COVID-19 Vaccines/immunology , COVID-19/immunology , COVID-19/virology , SARS-CoV-2/genetics , SARS-CoV-2/immunology , Antibodies, Monoclonal/chemistry , Antibodies, Neutralizing/chemistry , Binding Sites , COVID-19/prevention & control , COVID-19 Vaccines/administration & dosage , Cell Line , Host-Pathogen Interactions , Humans , Immune Sera , Models, Molecular , Mutation , Neutralization Tests , Protein Binding , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/immunology , Structure-Activity Relationship , Viral Pseudotyping
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