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1.
Antibiotics (Basel) ; 12(5)2023 May 18.
Article in English | MEDLINE | ID: covidwho-20233398

ABSTRACT

The most common resistance mechanism to carbapenems is the production of carbapenemases. In 2021, the Pan American Health Organization warned of the emergence and increase in new carbapenemase combinations in Enterobacterales in Latin America. In this study, we characterized four Klebsiella pneumoniae isolates harboring blaKPC and blaNDM from an outbreak during the COVID-19 pandemic in a Brazilian hospital. We assessed their plasmids' transference ability, fitness effects, and relative copy number in different hosts. The K. pneumoniae BHKPC93 and BHKPC104 strains were selected for whole genome sequencing (WGS) based on their pulsed-field gel electrophoresis profile. The WGS revealed that both isolates belong to ST11, and 20 resistance genes were identified in each isolate, including blaKPC-2 and blaNDM-1. The blaKPC gene was present on a ~56 Kbp IncN plasmid and the blaNDM-1 gene on a ~102 Kbp IncC plasmid, along with five other resistance genes. Although the blaNDM plasmid contained genes for conjugational transfer, only the blaKPC plasmid conjugated to E. coli J53, without apparent fitness effects. The minimum inhibitory concentrations (MICs) of meropenem/imipenem against BHKPC93 and BHKPC104 were 128/64 and 256/128 mg/L, respectively. Although the meropenem and imipenem MICs against E. coli J53 transconjugants carrying the blaKPC gene were 2 mg/L, this was a substantial increment in the MIC relative to the original J53 strain. The blaKPC plasmid copy number was higher in K. pneumoniae BHKPC93 and BHKPC104 than in E. coli and higher than that of the blaNDM plasmids. In conclusion, two ST11 K. pneumoniae isolates that were part of a hospital outbreak co-harbored blaKPC-2 and blaNDM-1. The blaKPC-harboring IncN plasmid has been circulating in this hospital since at least 2015, and its high copy number might have contributed to the conjugative transfer of this particular plasmid to an E. coli host. The observation that the blaKPC-containing plasmid had a lower copy number in this E. coli strain may explain why this plasmid did not confer phenotypic resistance against meropenem and imipenem.

2.
Topics in Antiviral Medicine ; 31(2):136, 2023.
Article in English | EMBASE | ID: covidwho-2313319

ABSTRACT

Background: Plasmacytoid dendritic cells (pDCs) are the major producer of type I IFNs (IFN-I), the critically important antiviral cytokines against SARS-CoV- 2. Although pDCs can sense cell-free SARS-CoV-2 virions, it is unknown whether they can detect infected cells to produce IFN-I. Since cell-to-cell transmission accounts for 90% of SARS-CoV-2 infections (Zeng et al., 2022), we examined the relevance of pDC sensing of infected cells in SARS-CoV-2 infection and whether the virus exploits this pathway to evade IFN-I responses. Method(s): LSPQ1, the first SARS-CoV-2 clinical isolate received from the Public Health Laboratory of Quebec, was used as a prototype virus. SARS-CoV-2 variants of concerns (VOCs) were also used. PBMCs or enriched pDCs were cocultured with mock-infected or SARS-CoV-2-infected HeLa-hACE2 or Calu-3. Either PBMCs, enriched pDCs, or HeLa-hACE2 were pretreated with anti-human ICAM-1 antibody or isotype control. The conjugate formation was determined by flow cytometry. Polarized Caco cells were used to validate critical data. Result(s): Upon sensing infected cells, PBMCs release 6-fold more IFN-I than they do when exposed to cell-free virions. Antibody-mediated depletion of pDCs from PBMCs abolishes IFN-I secretion. Direct contact of pDCs with infected cells is required for sensing since the use of a transwell membrane reduces IFN-I release by 85%. Infected cells form conjugates with pDCs more frequently (3.2-fold higher) than uninfected cells. Blocking ICAM-1 on infected cells or pDCs impacts conjugate formation and significantly suppresses IFN-I production by 55-80%, suggesting bidirectional interaction. Moreover, human lung cells infected with VOCs are sensed to a different extent with the alpha variant being the least efficiently sensed by pDCs compared to the delta or omicron strains. Even though SARS-CoV-2 is primarily released from the apical domain of polarized infected Caco cells, sensing of infected cells does occur upon direct contact of pDCs with the basolateral domain, highlighting how pDCs antiviral responses might be triggered in respiratory tissues. Conclusion(s): pDC sensing of infected cells accounts for the vast majority of IFN-I released during SARS-CoV-2 infection. ICAM-1 promotes physical contact between pDCs and infected cells, thus leading to efficient sensing. Differential pDC sensing of SARS-CoV-2 VOC-infected cells suggests that some VOCs might manipulate the interactions of pDCs with infected cells to limit IFN-I responses.

3.
Sci Total Environ ; 887: 163781, 2023 Aug 20.
Article in English | MEDLINE | ID: covidwho-2309588

ABSTRACT

During the pandemic of COVID-19, the amounts of quaternary ammonium compounds (QACs) used to inactivate the virus in public facilities, hospitals and households increased, which raised concerns about the evolution and transmission of antimicrobial resistance (AMR). Although QACs may play an important role in the propagation of antibiotic resistance gene (ARGs), the potential contribution and mechanism remains unclear. Here, the results showed that benzyl dodecyl dimethyl ammonium chloride (DDBAC) and didecyl dimethyl ammonium chloride (DDAC) significantly promoted plasmid RP4-mediated ARGs transfer within and across genera at environmental relevant concentrations (0.0004-0.4 mg/L). Low concentrations of QACs did not contribute to the permeability of the cell plasma membrane, but significantly increased the permeability of the cell outer membrane due to the decrease in content of lipopolysaccharides. QACs altered the composition and content of extracellular polymeric substances (EPS) and were positively correlated with the conjugation frequency. Furthermore, transcriptional expression levels of genes encode for mating pairing formation (trbB), DNA replication and translocation (trfA), and global regulators (korA, korB, trbA) are regulated by QACs. And we demonstrate for the first time that QACs decreased the concentration of extracellular AI-2 signals, which was verified to be involved in regulating conjugative transfer genes (trbB, trfA). Collectively, our findings underscore the risk of increased disinfectant concentrations of QACs on the ARGs transfer and provide new mechanisms of plasmid conjugation.


Subject(s)
COVID-19 , Quaternary Ammonium Compounds , Humans , Ammonium Chloride , Drug Resistance, Microbial/genetics , Anti-Bacterial Agents/pharmacology , Genes, Bacterial , Plasmids
4.
J Colloid Interface Sci ; 634: 963-971, 2023 Mar 15.
Article in English | MEDLINE | ID: covidwho-2244438

ABSTRACT

HYPOTHESIS: Virus-like particles (VLPs) are promising scaffolds for developing mucosal vaccines. For their optimal performance, in addition to design parameters from an immunological perspective, biophysical properties may need to be considered. EXPERIMENTS: We investigated the mechanical properties of VLPs scaffolded on the coat protein of Acinetobacter phage AP205 using atomic force microscopy and small angle X-ray scattering. FINDINGS: Investigations showed that AP205 VLP is a tough nanoshell of stiffness 93 ± 23 pN/nm and elastic modulus 0.11 GPa. However, its mechanical properties are modulated by attaching muco-inert polyethylene glycol to 46 ± 10 pN/nm and 0.05 GPa. Addition of antigenic peptides derived from SARS-CoV2 spike protein by genetic fusion increased the stiffness to 146 ± 54 pN/nm although the elastic modulus remained unchanged. These results, which are interpreted in terms of shell thickness and coat protein net charge variations, demonstrate that surface conjugation can induce appreciable changes in the biophysical properties of VLP-scaffolded vaccines.


Subject(s)
Bacteriophages , COVID-19 , Vaccines, Virus-Like Particle , Humans , Vaccines, Virus-Like Particle/chemistry , RNA, Viral , SARS-CoV-2
5.
Eur Polym J ; 184: 111767, 2023 Feb 07.
Article in English | MEDLINE | ID: covidwho-2158815

ABSTRACT

The global spread of SARS-CoV-2 (severe acute respiratory syndrome coronavirus-2) has caused the loss of many human lives and severe economic losses. SARS-CoV-2 mediates its infection in humans via the spike glycoprotein. The receptor binding domain of the SARS-CoV-2 spike protein binds to its cognate receptor, angiotensin converting enzyme-2 (ACE2) to initiate viral entry. In this study, we examine how polymer modification of the spike protein receptor binding domain impacts binding to ACE2. The horseradish peroxidase conjugated receptor binding domain was modified with a range of polymers including hydrophilic N,N-dimethylacrylamide, hydrophobic N-isopropylacrylamide, cationic 3-(N,N-dimethylamino)propylacrylamide, and anionic 2-acrylamido-2-methylpropane sulfonic acid polymers. The effect of polymer chain length was observed using N,N-dimethylacrylamide polymers with degrees of polymerization of 5, 10 and 25. Polymer conjugation of the receptor binding domain significantly reduced the interaction with ACE2 protein, as determined by an enzyme-linked immunosorbent assay. Stability analysis showed that these conjugates remained highly stable even after seven days incubation at physiological temperature. Hence, this study provides a detailed view of the effect specific type of modification using a library of polymers with different functionalities in interrupting RBD-ACE2 interaction.

6.
Chirality ; 34(9): 1166-1190, 2022 09.
Article in English | MEDLINE | ID: covidwho-2084347

ABSTRACT

Polysaccharides arouse great interest due to their structure and unique properties, such as biocompatibility, biodegradability, and absence of toxicity. Polysaccharides from marine sources are particularly useful due to the wide variety of applications and biological activities. Chitosan, a deacetylated derivative of chitin, is an example of an interesting bioactive marine-derived polysaccharide. Moreover, a wide variety of chemical modifications and conjugation of chitosan with other bioactive molecules are responsible for improvements in physicochemical properties and biological activities, expanding the range of applications. An overview of the synthetic approaches for preparing chitosan, chitosan derivatives, and conjugates is described and discussed. A recent update of the biological activities and applications in different research fields, mainly focused on the last 5 years, is presented, highlighting current trends.


Subject(s)
Chitosan , Chitin/chemistry , Chitosan/chemistry , Chitosan/pharmacology , Polysaccharides/chemistry , Polysaccharides/pharmacology , Stereoisomerism
7.
Swiss Medical Weekly ; 152:11S, 2022.
Article in English | EMBASE | ID: covidwho-2040918

ABSTRACT

Introduction: Vaccines need to be rationally designed to be delivered to the immune system for maximizing induction of dynamic immune responses. Virus-like nanoparticles (VLPs) are ideal platforms for such 3D vaccines. Coronaviruses have recently gained a lot of attention, due to the ongoing pandemic caused by SARS-CoV-2 and previous endemics by MERS-CoV. Methods: We have provided proof of concepts in murine models for effective development of VLP-based vaccines against MERS-CoV and SASR-CoV-2. We have used chemical conjugation or genetic fusion techniques to display receptor-binding domain or motif on our immunologically optimized (CuMVTT -VLPs). These VLPs incorporate a tetanus toxin epitope and ssRNA, TLR7/8 ligands. The vaccines were tested in murine models. Results: The vaccines are stable for more than a year at 4°C and highly scalable. Vaccination using subcutaneous or intranasal routes are feasible with nanoparticles. We demonstrated that these vaccines are highly immunogenic in mice as well as rabbits and can induce high avidity antibodies compared to convalescent human sera. Furthermore, the induced antibodies are cross-reactive with different VoCs (in case of SARS-CoV-2). The longevity of the induced immune response lasted longer than 120 days. Conclusion: Collectively, we show that VLP-based vaccines can efficiently induce high specific anti-RBD and spike antibodies that effectively neutralize different Coronaviruses and their VoCs. As Coronaviruses represent a continuous global threat to human health, it seems rational to further develop these vaccines.

8.
Drug Development and Delivery ; 22(4):18-23, 2022.
Article in English | Scopus | ID: covidwho-2012508
9.
FEBS Open Bio ; 12:166-167, 2022.
Article in English | EMBASE | ID: covidwho-1976652

ABSTRACT

The recent SARS-CoV-2 pandemic brought awareness to the permanent dangers of viral infections and outbreaks. Beyond its inherent infections, several viruses such as Dengue (DENV), Zika (ZIKV), HIV and even SARS-CoV-2 have the potential to infect the brain, causing more aggressive and irreversible injuries. These brain infections are particularly hard to treat not only because the number of efficient antiviral drugs against these viruses is scarce, but also due to the restrictive permeability of the blood- brain barrier (BBB) that hinders brain drug-intake. To overcome these issues, we designed peptide-drug conjugates formed by covalent attachment of a BBB peptide shuttle and a broad-spectrum antiviral porphyrin drug. We synthesized eighteen novel peptide-porphyrins conjugates (PPCs) and tested their activity in vitro, both in BBB-translocation and antiviral capacity against DENV, ZIKV, HIV and SARS-CoV-2. Cytotoxicity towards pharmacologic relevant cell lines was also studied. After careful fine-tuning of the on-resin synthetic chemistry, DIC/Oxyma coupling has emerged as preferred method, bearing a 99% conjugation yield. Ten PPCs inactivate at least two different viruses in vitro, a selection criterion for further evaluation, with IC50s ranging between 0.5 to 33 lM. Although all ten PPCs efficiently translocate the cellular BBB model in vitro, a set of seven stand out as the most druggable since they are not cytotoxic towards all cell lines tested. Overall, peptide-porphyrin conjugation shows to be an innovative and promising strategy to treat viral brain infections.

10.
FEBS Open Bio ; 12:265, 2022.
Article in English | EMBASE | ID: covidwho-1976646

ABSTRACT

For decades, scientific efforts were focused on the improvement of the effectiveness of the therapeutic antibodies, mainly in order reduce the dosage and thus lower the side-effects and costs. P4A1, a potent SARS-CoV-2 virus neutralizing antibody was already engineered to contain Fc fragment mutations, that dramatically increased the blood circulation time. In this work, we aimed to further enhance this neutralizing antibody efficacy by creating a next-generation virus neutralizing agent based on the P4A1 and conjugated with a highly processive Bacillus amyloliquefaciens RNase (barnase). Barnase itself is known to act as a mild toxin that drives the cells to apoptosis, and we propose that its RNase activity may enhance the protective effect through the hydrolysis of viral RNA in infected cells, and thereby additionally preventing pathogen replication. The main challenge in the assembly of such molecule is the intrinsic barnase toxicity in mammalian cells, what precludes the possibility to express it as a fusion protein. Further, we had shown that barnase, being a small (12.5 kDa) protein, contains very few surface reactive moieties that are available for conventional chemical crosslinking strategies. Therefore, the antibody-barnase fusion protein was obtained by enzymatic conjugation via the sortase A enzyme. The reaction conditions for bacterially expressed barnase and HEK293 derived P4A1 modified to contain heavy chain C-terminal sortase motif were thoroughly optimized and the reaction yield approached 80%. The immunotoxin RBD binding EC50 was not found to differ from the unconjugated P4A1 antibody and barnase activity was found to be 33% of the one for unmodified enzyme. Thus, we obtained the promising immunotoxin with a good yield, which had retained its RNase activity for the further in vitro virus neutralization studies.

12.
Advanced Materials ; 34(21):2270160, 2022.
Article in English | Wiley | ID: covidwho-1866500

ABSTRACT

Nanoparticle Vaccines In article number 2200443, Liangzhi Xie, Chengfeng Qin, and co-workers develop a novel bivalent nanoparticle vaccine that confers protection against infection of multiple SARS-CoV-2 variants and Streptococcus pneumoniae. This universal polysaccharide?protein-conjugated vaccine platform provides a powerful tool to fight against cocirculating viral and bacterial pathogens worldwide.

13.
Adv Mater ; 34(21): e2200443, 2022 May.
Article in English | MEDLINE | ID: covidwho-1763176

ABSTRACT

The ongoing COVID-19 pandemic caused by SARS-CoV-2 has led to millions of deaths worldwide. Streptococcus pneumoniae (S. pneumoniae) remains a major cause of mortality in underdeveloped countries. A vaccine that prevents both SARS-CoV-2 and S. pneumoniae infection represents a long-sought "magic bullet". Herein, a nanoparticle vaccine, termed SCTV01B, is rationally developed by using the capsular polysaccharide of S. pneumoniae serotype 14 (PPS14) as the backbone to conjugate with the recombinant receptor-binding domain (RBD) of the SARS-CoV-2 spike protein. The final formulation of conjugated nanoparticles in the network structure exhibits high thermal stability. Immunization with SCTV01B induces potent humoral and Type 1/Type 2 T helper cell (Th1/Th2) cellular immune responses in mice, rats, and rhesus macaques. In particular, SCTV01B-immunized serum not only broadly cross-neutralizes all SARS-CoV-2 variants of concern (VOCs), including the most recent Omicron variant, but also shows high opsonophagocytic activity (OPA) against S. pneumoniae serotype 14. Finally, SCTV01B vaccination confers protection against challenges with the SARS-CoV-2 mouse-adapted strain and the original strain in established murine models. Collectively, these promising preclinical results support further clinical evaluation of SCTV01B, highlighting the potency of polysaccharide-RBD-conjugated nanoparticle vaccine platforms for the development of vaccines for COVID-19 and other infectious diseases.


Subject(s)
COVID-19 , Nanoparticles , Vaccines , Animals , Antibodies, Neutralizing , Antibodies, Viral , COVID-19/prevention & control , COVID-19 Vaccines , Humans , Macaca mulatta/metabolism , Mice , Nanoparticles/chemistry , Pandemics , Polysaccharides , Rats , SARS-CoV-2 , Spike Glycoprotein, Coronavirus , Streptococcus pneumoniae/metabolism
14.
Talanta ; 244: 123381, 2022 Jul 01.
Article in English | MEDLINE | ID: covidwho-1747550

ABSTRACT

The early diagnosis of Coronavirus disease (COVID-19) requires either an accurate detection of genetic material or a sensitive detection of viral proteins. In this work, we designed an immunoassay platform for detecting trace levels of SARS-CoV-2 spike (S) protein. It is based on surface-enhanced resonance Raman scattering (SERRS) of methylene blue (MB) adsorbed onto spherical gold nanoparticles (AuNPs) and coated with a 6 nm silica shell. The latter shell in the SERRS nanoprobe prevented aggregation and permitted functionalization with SARS-CoV-2 antibodies. Specificity of the immunoassay was achieved by combining this functionalization with antibody immobilization on the cover slides that served as the platform support. Different concentrations of SARS-CoV-2 antigen could be distinguished and the lack of influence of interferents was confirmed by treating SERRS data with the multidimensional projection technique Sammon's mapping. With SERRS using a laser line at 633 nm, the lowest concentration of spike protein detected was 10 pg/mL, achieving a limit of detection (LOD) of 0.046 ng/mL (0.60 pM). This value is comparable to the lowest concentrations in the plasma of COVID-19 patients at the onset of symptoms, thus indicating that the SERRS immunoassay platform may be employed for early diagnosis.


Subject(s)
Biosensing Techniques , COVID-19 , Metal Nanoparticles , Biosensing Techniques/methods , COVID-19/diagnosis , Gold , Humans , Immunoassay/methods , SARS-CoV-2 , Spectrum Analysis, Raman , Spike Glycoprotein, Coronavirus
15.
Int J Mol Sci ; 23(3)2022 Jan 25.
Article in English | MEDLINE | ID: covidwho-1686811

ABSTRACT

Antibody-enzyme complexes (AECs) are ideal molecular recognition elements for immunosensing applications. One molecule possesses both a binding ability to specific targets and catalytic activity to gain signals, particularly oxidoreductases, which can be integrated into rapid and sensitive electrochemical measurements. The development of AECs using fragment antibodies rather than intact antibodies, such as immunoglobulin G (IgG), has attracted attention for overcoming the ethical and cost issues associated with the production of intact antibodies. Conventionally, chemical conjugation has been used to fabricate AECs; however, controlling stoichiometric conjugation using this method is difficult. To prepare homogeneous AECs, methods based on direct fusion and enzymatic conjugation have been developed, and more convenient methods using Catcher/Tag systems as coupling modules have been reported. In this review, we summarize the methods for fabricating AECs using fragment antibodies developed for sensing applications and discuss the advantages and disadvantages of each method.


Subject(s)
Antibodies/immunology , Immunoassay/methods , Multienzyme Complexes/immunology , Animals , Humans , Immunoglobulin G/immunology
16.
R Soc Open Sci ; 8(9): 211016, 2021 Sep.
Article in English | MEDLINE | ID: covidwho-1459097

ABSTRACT

Detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antigens in the fluid has important uses in biotechnology, and is integral to many point-of-care SARS-CoV-2 diagnostics. Sandwich enzyme-linked immunosorbent assays (ELISAs) are a sensitive, well-established method of measuring antigens in solutions. They use one ligand to capture and the other ligand to detect the target analyte. Detection is commonly achieved using colorimetric readout obtained upon the reaction of a substrate with HRP-conjugated secondary ligand. Nanobodies, the VHH domain of camelid antibodies, have expanded the repertoire of molecules used in antigen detection. Nanobodies' high affinity for target antigens, their compact structure, their high stability and ease of production has driven research into their use as diagnostic reagents. Guided by a structural understanding of epitopes on the receptor-binding domain of the SARS-CoV-2 Spike protein, we investigated various combinations of engineered nanobodies in a sandwich ELISA to detect the Spike protein of SARS-CoV-2. We have identified an optimal combination of nanobodies. These were selectively functionalized to further improve antigen capture, enabling the measurement of sub-picomolar amounts of SARS-CoV-2 Spike protein in solution. With this combination, the routine detection limit in samples inactivated by heat and detergent corresponded to less than seven focus-forming units of infectious SARS-CoV-2.

17.
Chembiochem ; 22(22): 3199-3207, 2021 11 16.
Article in English | MEDLINE | ID: covidwho-1406083

ABSTRACT

Site-specific protein modifications are vital for biopharmaceutical drug development. Gluconoylation is a non-enzymatic, post-translational modification of N-terminal HisTags. We report high-yield, site-selective in vitro α-aminoacylation of peptides, glycoproteins, antibodies, and virus-like particles (VLPs) with azidogluconolactone at pH 7.5 in 1 h. Conjugates slowly hydrolyse, but diol-masking with borate esters inhibits reversibility. In an example, we multimerise azidogluconoylated SARS-CoV-2 receptor-binding domain (RBD) onto VLPs via click-chemistry, to give a COVID-19 vaccine. Compared to yeast antigen, HEK-derived RBD was immunologically superior, likely due to observed differences in glycosylation. We show the benefits of ordered over randomly oriented multimeric antigen display, by demonstrating single-shot seroconversion and best virus-neutralizing antibodies. Azidogluconoylation is simple, fast and robust chemistry, and should accelerate research and development.


Subject(s)
Azides/chemistry , COVID-19 Vaccines/chemistry , Gluconates/chemistry , Glycine/chemistry , Histidine/chemistry , Lactones/chemistry , Vaccines, Virus-Like Particle/chemistry , Antibodies, Neutralizing/chemistry , Antibodies, Neutralizing/immunology , Azides/immunology , COVID-19 Vaccines/immunology , Gluconates/immunology , Glycine/immunology , Histidine/immunology , Humans , Lactones/immunology , Models, Molecular , Molecular Structure , Vaccines, Virus-Like Particle/immunology
18.
Anal Chim Acta ; 1189: 338907, 2022 Jan 02.
Article in English | MEDLINE | ID: covidwho-1336175

ABSTRACT

The immunosensor has been proven a versatile tool to detect various analytes, such as food contaminants, pathogenic bacteria, antibiotics and biomarkers related to cancer. To fabricate robust and reproducible immunosensors with high sensitivity, the covalent immobilization of immunoglobulins (IgGs) in a site-specific manner contributes to better performance. Instead of the random IgG orientations result from the direct yet non-selective immobilization techniques, this review for the first time introduces the advances of stepwise yet site-selective conjugation strategies to give better biosensing efficiency. Noncovalently adsorbing IgGs is the first but decisive step to interact specifically with the Fc fragment, then following covalent conjugate can fix this uniform and antigens-favorable orientation irreversibly. In this review, we first categorized this stepwise strategy into two parts based on the different noncovalent interactions, namely adhesive layer-mediated interaction onto homofunctional support and layer-free interaction onto heterofunctional support (which displays several different functionalities on its surface that are capable to interact with IgGs). Further, the influence of ligands characteristics (synthesis strategies, spacer requirements and matrices selection) on the heterofunctional support has also been discussed. Finally, conclusions and future perspectives for the real-world application of stepwise covalent conjugation are discussed. This review provides more insights into the fabrication of high-efficiency immunosensor, and special attention has been devoted to the well-orientation of full-length IgGs onto the sensing platform.


Subject(s)
Antibodies, Immobilized , Biosensing Techniques , Antibodies , Immunoassay , Immunoglobulin Fc Fragments
19.
ACS Nano ; 15(2): 2738-2752, 2021 02 23.
Article in English | MEDLINE | ID: covidwho-1036015

ABSTRACT

The coronavirus disease pandemic of 2019 (COVID-19) caused by the novel SARS-CoV-2 coronavirus resulted in economic losses and threatened human health worldwide. The pandemic highlights an urgent need for a stable, easily produced, and effective vaccine. SARS-CoV-2 uses the spike protein receptor-binding domain (RBD) to bind its cognate receptor, angiotensin-converting enzyme 2 (ACE2), and initiate membrane fusion. Thus, the RBD is an ideal target for vaccine development. In this study, we designed three different RBD-conjugated nanoparticle vaccine candidates, namely, RBD-Ferritin (24-mer), RBD-mi3 (60-mer), and RBD-I53-50 (120-mer), via covalent conjugation using the SpyTag-SpyCatcher system. When mice were immunized with the RBD-conjugated nanoparticles (NPs) in conjunction with the AddaVax or Sigma Adjuvant System, the resulting antisera exhibited 8- to 120-fold greater neutralizing activity against both a pseudovirus and the authentic virus than those of mice immunized with monomeric RBD. Most importantly, sera from mice immunized with RBD-conjugated NPs more efficiently blocked the binding of RBD to ACE2 in vitro, further corroborating the promising immunization effect. Additionally, the vaccine has distinct advantages in terms of a relatively simple scale-up and flexible assembly. These results illustrate that the SARS-CoV-2 RBD-conjugated nanoparticles developed in this study are a competitive vaccine candidate and that the carrier nanoparticles could be adopted as a universal platform for a future vaccine development.


Subject(s)
Angiotensin-Converting Enzyme 2/metabolism , COVID-19 Vaccines/therapeutic use , COVID-19/prevention & control , Nanoparticles/therapeutic use , SARS-CoV-2/physiology , Spike Glycoprotein, Coronavirus/metabolism , Animals , COVID-19/metabolism , COVID-19 Vaccines/pharmacology , Chlorocebus aethiops , Female , HEK293 Cells , Host-Pathogen Interactions , Humans , Mice , Mice, Inbred BALB C , Models, Molecular , Protein Binding , Protein Interaction Domains and Motifs , Spike Glycoprotein, Coronavirus/chemistry , Vero Cells
20.
J Nanobiotechnology ; 18(1): 130, 2020 Sep 10.
Article in English | MEDLINE | ID: covidwho-755216

ABSTRACT

Fast point-of-care (POC) diagnostics represent an unmet medical need and include applications such as lateral flow assays (LFAs) for the diagnosis of sepsis and consequences of cytokine storms and for the treatment of COVID-19 and other systemic, inflammatory events not caused by infection. Because of the complex pathophysiology of sepsis, multiple biomarkers must be analyzed to compensate for the low sensitivity and specificity of single biomarker targets. Conventional LFAs, such as gold nanoparticle dyed assays, are limited to approximately five targets-the maximum number of test lines on an assay. To increase the information obtainable from each test line, we combined green and red emitting quantum dots (QDs) as labels for C-reactive protein (CRP) and interleukin-6 (IL-6) antibodies in an optical duplex immunoassay. CdSe-QDs with sharp and tunable emission bands were used to simultaneously quantify CRP and IL-6 in a single test line, by using a single UV-light source and two suitable emission filters for readout through a widely available BioImager device. For image and data processing, a customized software tool, the MultiFlow-Shiny app was used to accelerate and simplify the readout process. The app software provides advanced tools for image processing, including assisted extraction of line intensities, advanced background correction and an easy workflow for creation and handling of experimental data in quantitative LFAs. The results generated with our MultiFlow-Shiny app were superior to those generated with the popular software ImageJ and resulted in lower detection limits. Our assay is applicable for detecting clinically relevant ranges of both target proteins and therefore may serve as a powerful tool for POC diagnosis of inflammation and infectious events.


Subject(s)
Biomarkers/analysis , C-Reactive Protein/analysis , Immunoassay/methods , Interleukin-6/analysis , Quantum Dots/chemistry , Sepsis/diagnosis , Antibodies/immunology , Betacoronavirus/isolation & purification , C-Reactive Protein/immunology , COVID-19 , Coronavirus Infections/diagnosis , Coronavirus Infections/virology , Humans , Interleukin-6/immunology , Limit of Detection , Pandemics , Pneumonia, Viral/diagnosis , Pneumonia, Viral/virology , Point-of-Care Systems , SARS-CoV-2 , Sepsis/metabolism , Software , Ultraviolet Rays
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