scholarly journals SARS-CoV-2 Antigens Expressed in Plants Detect Antibody Responses in COVID-19 Patients

2021 ◽  
Vol 12 ◽  
Author(s):  
Mohau S. Makatsa ◽  
Marius B. Tincho ◽  
Jerome M. Wendoh ◽  
Sherazaan D. Ismail ◽  
Rofhiwa Nesamari ◽  
...  
Keyword(s):  
High Sensitivity ◽  
High Specificity ◽  
Viral Proteins ◽  
Antibody Responses ◽  
Robust Detection ◽  
Recombinant Plant ◽  
Specific Igg ◽  
African Patients ◽  
Global Threat ◽  
Humoral Responses

Background: The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has swept the world and poses a significant global threat to lives and livelihoods, with 115 million confirmed cases and at least 2.5 million deaths from Coronavirus disease 2019 (COVID-19) in the first year of the pandemic. Developing tools to measure seroprevalence and understand protective immunity to SARS-CoV-2 is a priority. We aimed to develop a serological assay using plant-derived recombinant viral proteins, which represent important tools in less-resourced settings.Methods: We established an indirect ELISA using the S1 and receptor-binding domain (RBD) portions of the spike protein from SARS-CoV-2, expressed in Nicotiana benthamiana. We measured antibody responses in sera from South African patients (n = 77) who had tested positive by PCR for SARS-CoV-2. Samples were taken a median of 6 weeks after the diagnosis, and the majority of participants had mild and moderate COVID-19 disease. In addition, we tested the reactivity of pre-pandemic plasma (n = 58) and compared the performance of our in-house ELISA with a commercial assay. We also determined whether our assay could detect SARS-CoV-2-specific IgG and IgA in saliva.Results: We demonstrate that SARS-CoV-2-specific immunoglobulins are readily detectable using recombinant plant-derived viral proteins, in patients who tested positive for SARS-CoV-2 by PCR. Reactivity to S1 and RBD was detected in 51 (66%) and 48 (62%) of participants, respectively. Notably, we detected 100% of samples identified as having S1-specific antibodies by a validated, high sensitivity commercial ELISA, and optical density (OD) values were strongly and significantly correlated between the two assays. For the pre-pandemic plasma, 1/58 (1.7%) of samples were positive, indicating a high specificity for SARS-CoV-2 in our ELISA. SARS-CoV-2-specific IgG correlated significantly with IgA and IgM responses. Endpoint titers of S1- and RBD-specific immunoglobulins ranged from 1:50 to 1:3,200. S1-specific IgG and IgA were found in saliva samples from convalescent volunteers.Conclusion: We demonstrate that recombinant SARS-CoV-2 proteins produced in plants enable robust detection of SARS-CoV-2 humoral responses. This assay can be used for seroepidemiological studies and to measure the strength and durability of antibody responses to SARS-CoV-2 in infected patients in our setting.

scholarly journals SARS-CoV-2 antigens expressed in plants detect antibody responses in COVID-19 patients

2020 ◽  
Author(s):  
Mohau S. Makatsa ◽  
Marius B. Tincho ◽  
Jerome M. Wendoh ◽  
Sherazaan D. Ismail ◽  
Rofhiwa Nesamari ◽  
...  
Keyword(s):  
High Sensitivity ◽  
High Specificity ◽  
Viral Proteins ◽  
Antibody Responses ◽  
Enzyme Linked Immunosorbent Assay ◽  
Robust Detection ◽  
Recombinant Plant ◽  
Specific Igg ◽  
African Patients ◽  
Global Threat

AbstractBackgroundThe SARS-CoV-2 pandemic has swept the world and poses a significant global threat to lives and livelihoods, with over 16 million confirmed cases and at least 650 000 deaths from COVID-19 in the first 7 months of the pandemic. Developing tools to measure seroprevalence and understand protective immunity to SARS-CoV-2 is a priority. We aimed to develop a serological assay using plant-derived recombinant viral proteins, which represent important tools in less-resourced settings.MethodsWe established an indirect enzyme-linked immunosorbent assay (ELISA) using the S1 and receptor-binding domain (RBD) portions of the spike protein from SARS-CoV-2, expressed in Nicotiana benthamiana. We measured antibody responses in sera from South African patients (n=77) who had tested positive by PCR for SARS-CoV-2. Samples were taken a median of six weeks after the diagnosis, and the majority of participants had mild and moderate COVID-19 disease. In addition, we tested the reactivity of pre-pandemic plasma (n=58) and compared the performance of our in-house ELISA with a commercial assay. We also determined whether our assay could detect SARS-CoV-2-specific IgG and IgA in saliva.ResultsWe demonstrate that SARS-CoV-2-specific immunoglobulins are readily detectable using recombinant plant-derived viral proteins, in patients who tested positive for SARS-CoV-2 by PCR. Reactivity to S1 and RBD was detected in 51 (66%) and 48 (62%) of participants, respectively. Notably, we detected 100% of samples identified as having S1-specific antibodies by a validated, high sensitivity commercial ELISA, and OD values were strongly and significantly correlated between the two assays. For the pre-pandemic plasma, 1/58 (1.7%) of samples were positive, indicating a high specificity for SARS-CoV-2 in our ELISA. SARS-CoV-2-specific IgG correlated significantly with IgA and IgM responses. Endpoint titers of S1- and RBD-specific immunoglobulins ranged from 1:50 to 1:3200. S1-specific IgG and IgA were found in saliva samples from convalescent volunteers.ConclusionsWe demonstrate that recombinant SARS-CoV-2 proteins produced in plants enable robust detection of SARS-CoV-2 humoral responses. This assay can be used for seroepidemiological studies and to measure the strength and durability of antibody responses to SARS-CoV-2 in infected patients in our setting.

scholarly journals SARS-CoV2 envelop proteins reshape the serological responses of COVID-19 patients

2021 ◽  
Author(s):  
Sophie Martin ◽  
Christopher Heslan ◽  
Gwénaële Jégou ◽  
Leif A. Eriksson ◽  
Matthieu Le Gallo ◽  
...  
Keyword(s):  
Viral Proteins ◽  
The Body ◽  
Membrane Insertion ◽  
Host Immune System ◽  
Topological Features ◽  
Viral Particles ◽  
M Proteins ◽  
Serological Status ◽  
Specific Igg ◽  
Humoral Responses

AbstractThe SARS-CoV-2 pandemic has elicited a unique international mobilization of the scientific community to better understand this coronavirus and its associated disease and to develop efficient tools to combat infection. Similar to other coronavirae, SARS-CoV-2 hijacks the host cell complex secretory machinery to produce properly folded viral proteins that will compose the nascent virions; including Spike, Envelope and Membrane proteins, the most exposed membrane viral proteins to the host immune system. Antibody response is part of the anti-viral immune arsenal that infected patients develop to fight viral particles in the body. Herein, we investigate the immunogenic potential of Spike (S), Envelope (E) and Membrane (M) proteins using a human cell-based system to mimic membrane insertion and N-glycosylation. We show that both S and M proteins elicit the production of specific IgG, IgM and IgA in SARS-CoV-2 infected patients. Elevated Ig responses were observed in COVID+ patients with moderate and severe forms of the disease. Finally, when SARS-CoV-2 Spike D614 and G614 variants were compared, reduced Ig binding was observed with the Spike G614 variant. Altogether, this study underlines the needs for including topological features in envelop proteins to better characterize the serological status of COVID+ patients, points towards an unexpected immune response against the M protein and shows that our assay could represent a powerful tool to test humoral responses against actively evolving SARS-CoV-2 variants and vaccine effectiveness.

scholarly journals Phase I assessments of first-in-human administration of a novel malaria anti-sporozoite vaccine candidate, R21 in matrix-M adjuvant, in UK and Burkinabe volunteers

2019 ◽  
Author(s):  
Navin Venkatraman ◽  
Alfred B. Tiono ◽  
Georgina Bowyer ◽  
Jonathan Powlson ◽  
Katharine A. Collins ◽  
...  
Keyword(s):  
Vaccine Candidate ◽  
Hepatitis B Surface Antigen ◽  
Controlled Trial ◽  
Cost Effective ◽  
Antibody Responses ◽  
Open Label ◽  
Malaria Vaccine Candidate ◽  
Specific Igg ◽  
Randomised Controlled ◽  
Humoral Responses

ABSTRACTBackgroundImprovements in malaria control have stalled recently and new tools are needed. The R21 vaccine is comprised of the malaria circumsporozoite protein fused to hepatitis B surface antigen (HBsAg). It forms particles that lack the excess HBsAg in the frequently tested malaria vaccine candidate, RTS,S/AS01B.MethodsWe conducted an open-label, first-in-human, Phase Ia study evaluating safety and immunogenicity of R21 administered alone and with the saponin-based adjuvant, Matrix-M™ (MM). Twenty-eight healthy adults received three doses of R21 given intramuscularly 4 weeks apart. We subsequently conducted a Phase Ib randomised, controlled trial in West African adults.FindingsVaccinations were well tolerated, and the majority of local and systemic adverse events were mild. Reactogenicity was significantly lower in Burkinabe than UK vaccinees (p<0.0001). Antibody responses increased significantly 28 days after the 2nd vaccination in UK volunteers. Antibody responses to R21 in all dose groups (2μg, 10μg and 50μg) were comparable to those of 50μg RTS,S/AS01B in malaria-naïve adults at 28 days after final vaccination. The 10μg dose induced more durable responses, with 2-fold higher NANP-specific IgG titres at 6 months compared with the 2μg and 50μg dose groups. R21 also boosted baseline humoral responses in Burkinabe adults with well-maintained responses suggesting natural boosting.InterpretationR21 adjuvanted with MM is safe and has comparable immunogenicity to RTS,S/AS01B, even when administered at a five-fold lower 10μg dose in UK and African populations. This forms the basis for efficacy testing of this vaccine which could prove to be particularly cost-effective to manufacture and deploy.

scholarly journals Laboratory and Clinical Evaluation of DNA Microarray for the Detection of Carbapenemase Genes in Gram-Negative Bacteria from Hospitalized Patients

2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Yi Song ◽  
Fengna Dou ◽  
Sha He ◽  
Yu Zhou ◽  
Qiqi Liu
Keyword(s):  
Dna Microarray ◽  
High Throughput ◽  
Sanger Sequencing ◽  
Limit Of Detection ◽  
High Sensitivity ◽  
High Specificity ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Specificity And Sensitivity ◽  
Global Threat

Background. The prevalence of a variety of carbapenemases in Gram-negative bacteria (GNB) has posed a global threat on clinical control and management. Monitoring and controlling the carbapenemase-producing GNB became imperative tasks for many healthcare centers. The aim of this study was to develop a high-throughput, specific, sensitive, and rapid DNA microarray-based method for the diagnosis, phenotypic confirmation, and molecular epidemiological study of carbapenemase genes. Methods. We targeted a panel of eight carbapenemase genes, including blaKPC, blaNDM-1, blaOXA-23, blaOXA-48, blaOXA-51, blaIMP, blaVIM, and blaDIM for detection. Ultrasensitive chemiluminescence (CL) detection method was developed and used to simultaneously detect eight carbapenemase genes, and plasmids were established as positive or limit of detection (LOD) reference materials. Antibiotic susceptibility was determined by disk diffusion according to Clinical and Laboratory Standards Institute (CLSI) guidelines in order to screen clinical isolates resistant to carbapenem antibiotics as well as Sanger sequencing which was used to confirm the reliability of the results presented by DNA microarray. Results. Eight carbapenemase genes could be detected with high sensitivity and specificity. The absolute LOD of this strategy to detect serially diluted plasmids of eight carbapenemase genes was 102- 103copies/μL. Then, 416 specimens collected from hospital were detected and the results showed 96.6% concordance between the phenotypic and microarray tests. Compared with Sanger sequencing, a specificity and sensitivity of 100% were recorded for blaNDM-1, blaIMP, blaVIM, and blaDIM genes. The specificity for blaKPC, blaOXA-23, blaOXA-48, and blaOXA-51 genes was 100% and the sensitivity was 98.5%, 97.6%, 95.7%, and 97.9%, respectively. The overall consistency rate between the sequencing and microarray is 97.8%. Conclusions. The proposed ultrasensitive CL imaging DNA hybridization has high specificity, sensitivity, and reproducibility and could detect and differentiate clinical specimens that carried various carbapenemase genes, suggesting that the method can conveniently be customized for high-throughput detection of the carbapenemase-producing GNB and can be easily adapted for various clinical applications.

scholarly journals From Multiplex Serology to Serolomics—A Novel Approach to the Antibody Response against the SARS-CoV-2 Proteome

Viruses ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 749
Author(s):  
Julia Butt ◽  
Rajagopal Murugan ◽  
Theresa Hippchen ◽  
Sylvia Olberg ◽  
Monique van Straaten ◽  
...  
Keyword(s):  
Antibody Response ◽  
High Throughput ◽  
Large Population ◽  
High Sensitivity ◽  
Population Based ◽  
Antibody Responses ◽  
Hek293 Cells ◽  
Novel Approach ◽  
Assay Performance ◽  
Multiplex Serology

The emerging SARS-CoV-2 pandemic entails an urgent need for specific and sensitive high-throughput serological assays to assess SARS-CoV-2 epidemiology. We, therefore, aimed at developing a fluorescent-bead based SARS-CoV-2 multiplex serology assay for detection of antibody responses to the SARS-CoV-2 proteome. Proteins of the SARS-CoV-2 proteome and protein N of SARS-CoV-1 and common cold Coronaviruses (ccCoVs) were recombinantly expressed in E. coli or HEK293 cells. Assay performance was assessed in a COVID-19 case cohort (n = 48 hospitalized patients from Heidelberg) as well as n = 85 age- and sex-matched pre-pandemic controls from the ESTHER study. Assay validation included comparison with home-made immunofluorescence and commercial enzyme-linked immunosorbent (ELISA) assays. A sensitivity of 100% (95% CI: 86–100%) was achieved in COVID-19 patients 14 days post symptom onset with dual sero-positivity to SARS-CoV-2 N and the receptor-binding domain of the spike protein. The specificity obtained with this algorithm was 100% (95% CI: 96–100%). Antibody responses to ccCoVs N were abundantly high and did not correlate with those to SARS-CoV-2 N. Inclusion of additional SARS-CoV-2 proteins as well as separate assessment of immunoglobulin (Ig) classes M, A, and G allowed for explorative analyses regarding disease progression and course of antibody response. This newly developed SARS-CoV-2 multiplex serology assay achieved high sensitivity and specificity to determine SARS-CoV-2 sero-positivity. Its high throughput ability allows epidemiologic SARS-CoV-2 research in large population-based studies. Inclusion of additional pathogens into the panel as well as separate assessment of Ig isotypes will furthermore allow addressing research questions beyond SARS-CoV-2 sero-prevalence.

scholarly journals Radiochemistry, Production Processes, Labeling Methods, and ImmunoPET Imaging Pharmaceuticals of Iodine-124

Molecules ◽  
2021 ◽  
Vol 26 (2) ◽  
pp. 414
Author(s):  
Krishan Kumar ◽  
Arijit Ghosh
Keyword(s):  
Physical Properties ◽  
Imaging Modality ◽  
Target Selection ◽  
Positron Emission Tomography Imaging ◽  
High Sensitivity ◽  
High Specificity ◽  
Production Processes ◽  
Positron Emission ◽  
Significant Research ◽  
Clinical Environments

Target-specific biomolecules, monoclonal antibodies (mAb), proteins, and protein fragments are known to have high specificity and affinity for receptors associated with tumors and other pathological conditions. However, the large biomolecules have relatively intermediate to long circulation half-lives (>day) and tumor localization times. Combining superior target specificity of mAbs and high sensitivity and resolution of the PET (Positron Emission Tomography) imaging technique has created a paradigm-shifting imaging modality, ImmunoPET. In addition to metallic PET radionuclides, 124I is an attractive radionuclide for radiolabeling of mAbs as potential immunoPET imaging pharmaceuticals due to its physical properties (decay characteristics and half-life), easy and routine production by cyclotrons, and well-established methodologies for radioiodination. The objective of this report is to provide a comprehensive review of the physical properties of iodine and iodine radionuclides, production processes of 124I, various 124I-labeling methodologies for large biomolecules, mAbs, and the development of 124I-labeled immunoPET imaging pharmaceuticals for various cancer targets in preclinical and clinical environments. A summary of several production processes, including 123Te(d,n)124I, 124Te(d,2n)124I, 121Sb(α,n)124I, 123Sb(α,3n)124I, 123Sb(3He,2n)124I, natSb(α, xn)124I, natSb(3He,n)124I reactions, a detailed overview of the 124Te(p,n)124I reaction (including target selection, preparation, processing, and recovery of 124I), and a fully automated process that can be scaled up for GMP (Good Manufacturing Practices) production of large quantities of 124I is provided. Direct, using inorganic and organic oxidizing agents and enzyme catalysis, and indirect, using prosthetic groups, 124I-labeling techniques have been discussed. Significant research has been conducted, in more than the last two decades, in the development of 124I-labeled immunoPET imaging pharmaceuticals for target-specific cancer detection. Details of preclinical and clinical evaluations of the potential 124I-labeled immunoPET imaging pharmaceuticals are described here.

scholarly journals SARS-CoV-2 specific antibody and neutralization assays reveal the wide range of the humoral immune response to virus

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Mikail Dogan ◽  
Lina Kozhaya ◽  
Lindsey Placek ◽  
Courtney Gunter ◽  
Mesut Yigit ◽  
...  
Keyword(s):  
Specific Antibody ◽  
Neutralizing Antibodies ◽  
Vaccine Development ◽  
High Specificity ◽  
Spike Protein ◽  
Humoral Immune ◽  
Specificity And Sensitivity ◽  
Wide Range ◽  
Specific Igg ◽  
Negative Controls

AbstractDevelopment of antibody protection during SARS-CoV-2 infection is a pressing question for public health and for vaccine development. We developed highly sensitive SARS-CoV-2-specific antibody and neutralization assays. SARS-CoV-2 Spike protein or Nucleocapsid protein specific IgG antibodies at titers more than 1:100,000 were detectable in all PCR+ subjects (n = 115) and were absent in the negative controls. Other isotype antibodies (IgA, IgG1-4) were also detected. SARS-CoV-2 neutralization was determined in COVID-19 and convalescent plasma at up to 10,000-fold dilution, using Spike protein pseudotyped lentiviruses, which were also blocked by neutralizing antibodies (NAbs). Hospitalized patients had up to 3000-fold higher antibody and neutralization titers compared to outpatients or convalescent plasma donors. Interestingly, some COVID-19 patients also possessed NAbs against SARS-CoV Spike protein pseudovirus. Together these results demonstrate the high specificity and sensitivity of our assays, which may impact understanding the quality or duration of the antibody response during COVID-19 and in determining the effectiveness of potential vaccines.

scholarly journals Highly Sensitive Fluorescent Detection of Acetylcholine Based on the Enhanced Peroxidase-Like Activity of Histidine Coated Magnetic Nanoparticles

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1207
Author(s):  
Hong Jae Cheon ◽  
Quynh Huong Nguyen ◽  
Moon Il Kim
Keyword(s):  
Magnetic Nanoparticles ◽  
High Sensitivity ◽  
High Specificity ◽  
Choline Oxidase ◽  
Fluorescent Detection ◽  
One Pot ◽  
Site Structure ◽  
Specificity And Sensitivity ◽  
Highly Sensitive ◽  
Peroxidase Mimics

Inspired by the active site structure of natural horseradish peroxidase having iron as a pivotal element with coordinated histidine residues, we have developed histidine coated magnetic nanoparticles (His@MNPs) with relatively uniform and small sizes (less than 10 nm) through one-pot heat treatment. In comparison to pristine MNPs and other amino acid coated MNPs, His@MNPs exhibited a considerably enhanced peroxidase-imitating activity, approaching 10-fold higher in catalytic reactions. With the high activity, His@MNPs then were exploited to detect the important neurotransmitter acetylcholine. By coupling choline oxidase and acetylcholine esterase with His@MNPs as peroxidase mimics, target choline and acetylcholine were successfully detected via fluorescent mode with high specificity and sensitivity with the limits of detection down to 200 and 100 nM, respectively. The diagnostic capability of the method is demonstrated by analyzing acetylcholine in human blood serum. This study thus demonstrates the potential of utilizing His@MNPs as peroxidase-mimicking nanozymes for detecting important biological and clinical targets with high sensitivity and reliability.

scholarly journals Insights into Antibody-Mediated Alphavirus Immunity and Vaccine Development Landscape

2021 ◽  
Vol 9 (5) ◽  
pp. 899
Author(s):  
Anthony Torres-Ruesta ◽  
Rhonda Sin-Ling Chee ◽  
Lisa F.P. Ng
Keyword(s):  
Diagnostic Tests ◽  
Inflammatory Arthritis ◽  
Chikungunya Virus ◽  
Vaccine Development ◽  
Antibody Responses ◽  
Chikv Infection ◽  
Wide Range ◽  
Susceptible Populations ◽  
Humoral Responses

Alphaviruses are mosquito-borne pathogens distributed worldwide in tropical and temperate areas causing a wide range of symptoms ranging from inflammatory arthritis-like manifestations to the induction of encephalitis in humans. Historically, large outbreaks in susceptible populations have been recorded followed by the development of protective long-lasting antibody responses suggesting a potential advantageous role for a vaccine. Although the current understanding of alphavirus antibody-mediated immunity has been mainly gathered in natural and experimental settings of chikungunya virus (CHIKV) infection, little is known about the humoral responses triggered by other emerging alphaviruses. This knowledge is needed to improve serology-based diagnostic tests and the development of highly effective cross-protective vaccines. Here, we review the role of antibody-mediated immunity upon arthritogenic and neurotropic alphavirus infections, and the current research efforts for the development of vaccines as a tool to control future alphavirus outbreaks.

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