scholarly journals 418. Comparison of the Abbott SARS-CoV-2 IgG and DiaSorin LIASON SARS-CoV-2 S1/S2 IgG Antibody Assays

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S276-S277
Author(s):  
Grace A Schaack ◽  
Derrick Chen
Keyword(s):  
Disease Surveillance ◽  
Neutralizing Antibodies ◽  
Infection Prevalence ◽  
Reference Laboratory ◽  
Igg Antibody ◽  
S Protein ◽  
N Protein ◽  
Negative Results ◽  
Antibody Assays ◽  
Lab Test

Abstract Background The Abbott Laboratories SARS-CoV-2 IgG assay and the DiaSorin LIASON SARS-CoV-2 S1/S2 IgG assay are both chemiluminescent immunoassays that qualitatively detect IgG antibodies against SARS-CoV-2 antigens. The Abbott assay detects IgG against the viral nucleocapsid (N) protein, while the DiaSorin assay uses antigen derived from the viral spike (S) protein. Here we evaluate the performance of these two assays at our institution. Methods 45 patient samples (serum or plasma) were tested for anti-SARS-CoV-2 IgG by both the Abbott and DiaSorin assays. The samples were previously characterized at a national reference laboratory using the Abbott assay or by an in-house PCR-based test for SARS-CoV-2 RNA. Samples yielding discordant results across platforms were further tested using the EUROIMMUN Anti-SARS-CoV-2 ELISA (IgG) assay at the reference laboratory. Results 22 samples tested negative for SARS-CoV-2 by the reference lab Abbott assay, and 23 tested positive by the same reference lab test (n = 13) or by an in-house PCR-based test (n = 10). The 22 samples characterized as negative again tested negative by both the Abbott (in-house) and DiaSorin assays (100% NPA). Among the 23 samples characterized as positive, all 23 tested positive by the Abbott assay (100% PPA), while only 15 tested positive by the DiaSorin assay (65% PPA). For each of the 8 discordant cases, samples were further tested by EUROIMMUN assay, which targets the S protein; 7 of the 8 samples tested negative by this assay, in agreement with the DiaSorin test results. Thus, for the discordant cases, testing for IgG against N (in-house and reference lab Abbott assays) gave positive results, while testing for IgG against S (DiaSorin and EUROIMMUN assays) mostly gave negative results. Conclusion These findings highlight the importance of the differences between various SARS-CoV-2 antibody tests, and providers should be aware of the specific antigenic target(s) in each test. Selection of a specific assay may depend on the need to assess past exposure to SARS-CoV-2 (for which a nucleocapsid target may be more sensitive) or to detect neutralizing antibodies (for which a spike target may be more relevant). This also has implications for disease surveillance as reliance on anti-spike antibodies alone may underestimate infection prevalence. Disclosures All Authors: No reported disclosures

scholarly journals Measles Virus Infection and Immunity in a Suboptimal Vaccination Coverage Setting

Vaccines ◽  
2019 ◽  
Vol 7 (4) ◽  
pp. 199 ◽  
Author(s):  
Monia Pacenti ◽  
Nataskya Maione ◽  
Enrico Lavezzo ◽  
Elisa Franchin ◽  
Federico Dal Bello ◽  
...  
Keyword(s):  
Vaccination Coverage ◽  
Neutralizing Antibodies ◽  
Measles Virus ◽  
High Efficiency ◽  
Vaccine Uptake ◽  
Reference Laboratory ◽  
Veneto Region ◽  
Igg Antibody ◽  
Measles Vaccination ◽  
Measles Outbreaks

Despite efforts to improve surveillance and vaccination coverage, measles virus (MeV) continues to cause outbreaks also in high-income countries. As the reference laboratory of the Veneto Region, Italy, we analyzed changes in population immunity, described measles outbreaks, investigated MeV genetic diversity, and evaluated cross-protection of measles vaccination against MeV epidemic strains. Like most European areas, the Veneto Region has suboptimal measles vaccination coverage and is facing a growing public mistrust of vaccination. A progressive decline of measles vaccine uptake was observed during the last decade in the Veneto Region, leading to immunity gaps in children and young adults. Measles outbreaks were caused by the same MeV genotype B3, D4, and D8 strains that were circulating in other European countries. Eleven cases of measles were observed in immunized subjects. These cases were not associated with particular MeV genotypes nor with mutations in epitopes recognized by neutralizing antibodies. Accordingly, sera from fully vaccinated subjects cross-neutralized epidemic MeV strains, including the genotypes B3, D4, and D8, with the same high efficiency demonstrated against the vaccine strain. In fully vaccinated subjects, high MeV IgG antibody titers persisted up to 30 years following vaccination. These results support the use of the current measles-containing vaccines and strategies to strengthen vaccination.

scholarly journals Circulating anti-SARS-CoV-2 nucleocapsid (N)-protein antibodies and anti-SARS-CoV-2 spike (S)-protein antibodies in an African setting: herd immunity, not there yet!

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Amandine Mveang Nzoghe ◽  
Marielle Leboueny ◽  
Eliane Kuissi Kamgaing ◽  
Anicet Christel Maloupazoa Siawaya ◽  
Eliode Cyrien Bongho ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Total Population ◽  
Herd Immunity ◽  
Humoral Response ◽  
S Protein ◽  
N Protein ◽  
African Context ◽  
African Setting

Abstract Objective Herd immunity is achieved when in a population, immune individuals are in a sufficiently large proportion. Neutralizing antibodies specific to SARS-CoV-2 that are produced following infection or vaccination are critical for controlling the spread of COVID-19. The objective of the present work was to investigate the rate of SARS-CoV-2 natural immunization in Gabonese. Results One thousand, four hundred and ninety two people were enrolled. The overall prevalence of anti-SARS-CoV-2 antibodies was 36.2%. Moreover, 76.4% of people who developed a humoral response to SARS-CoV-2 produced both anti-SARS-CoV-2 N-protein antibodies and anti-SARS-CoV-2 S-protein antibodies, which correspond to 27.7% of the total population. In infants (0–9 month), children (1–17 years) and adults, the prevalence of anti-SARS-CoV-2 antibodies was relatively the same, between 33 and 37% (any antibody types) and between 25 and 28.6% (neutralizing antibodies). In this African context, one-third (1/3) of the screened population was exposed to SARS-CoV-2 and three-quarter (3/4) of those exposed individuals developed neutralizing antibodies against SARS-CoV-2. This data suggest that herd immunity is not yet to be achieved in Gabon.

scholarly journals Evaluation of Three SARS CoV-2 IgG Antibody Assays and Correlation with Neutralizing Antibodies

2020 ◽  
Author(s):  
Jenna Rychert ◽  
Marc Roger Couturier ◽  
Marc Elgort ◽  
Bucky Ken Lozier ◽  
Sonia La’ulu ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Quantitative Result ◽  
Neutralizing Antibody ◽  
Performance Characteristics ◽  
Igg Antibody ◽  
Assay Sensitivity ◽  
Clinical Sensitivity ◽  
Antibody Assays ◽  
Comparable Performance ◽  
Sensitivity Specificity

Abstract Background As serologic assays for SARS-CoV-2 become more widely utilized, it is important to understand their performance characteristics and correlation with neutralizing antibodies. We evaluated three commonly used SARS-CoV-2 IgG assays (Abbott, DiaSorin and EUROIMMUN) for clinical sensitivity, specificity, and correlation with neutralizing antibodies and then compared antibody kinetics during the acute phase of infection. Methods Three panels of samples were tested on every assay. Sensitivity was assessed using a panel of 35 specimens serially collected from 7 RT-PCR-confirmed COVID-19 patients. Specificity was determined using 100 sera samples collected in 2018 from healthy individuals prior to the outbreak. Analytical specificity was determined using a panel of 37 samples from individuals with respiratory illnesses other than COVID-19. Results Clinical sensitivity was 91.43% (95% CI 76.94%-98.20%) for Abbott, and 88.57% (95% CI 73.26%-96.80%) for both DiaSorin and EUROIMMUN. Clinical specificity was 99.00% (95% CI 94.55%-99.97%) for Abbott and DiaSorin and 94.00% (95% CI 87.40%-97.77%) for EUROIMMUN. The IgG assays demonstrated good qualitative agreement (minimum of 94%) and good correlation between the quantitative result for each combination of assays (r2≥0.90). The neutralizing antibody response did not necessarily follow the same temporal kinetics as the IgG response and did not necessarily correlate with IgG values. Conclusion The three IgG antibody assays demonstrated comparable performance characteristics. Importantly, a qualitative positive IgG result obtained with any of the assays was associated with the presence of neutralizing antibodies; however, neutralizing antibody concentrations did not correlate well with signal to cutoff ratios.

scholarly journals New detection of SARS-CoV-2 in two cats height months after COVID-19 outbreak appearance in France

2021 ◽  
Author(s):  
Matthieu Fritz ◽  
Nicolas Nesi ◽  
Solene Denolly ◽  
Bertrand Boson ◽  
Vincent Legros ◽  
...  
Keyword(s):  
Comparative Analysis ◽  
Molecular Biology ◽  
Neutralizing Antibodies ◽  
Clinical Observation ◽  
Infection Status ◽  
Serological Analysis ◽  
S Protein ◽  
N Protein ◽  
Additional Information ◽  
Microsphere Immunoassay

Although there are several reports in the literature of SARS-CoV-2 infection in cats, few SARS-CoV-2 sequences from infected cats have been published. In this report, SARS-CoV-2 infection was evaluated in two cats by clinical observation, molecular biology (qPCR and NGS), and serology (Microsphere immunoassay and seroneutralization). Following the observation of symptomatic SARS-CoV-2-infection in two cats, infection status was confirmed by RT-qPCR and, in one cat, serological analysis for antibodies against N-protein and S-protein, as well as neutralizing antibodies. Comparative analysis of five SARS-CoV-2 sequence-fragments obtained from one of the cats showed that this infection was not with one of the three recently emerged variants of SARS-CoV-2. This study provides additional information on the clinical, molecular, and serological aspects of SARS-CoV-2 infection in cats.

scholarly journals Proteome-wide analysis of differentially-expressed SARS-CoV-2 antibodies in early COVID-19 infection

2020 ◽  
Author(s):  
Xiaomei Zhang ◽  
Xian Wu ◽  
Dan Wang ◽  
Minya Lu ◽  
Xin Hou ◽  
...  
Keyword(s):  
Early Stage ◽  
False Negative ◽  
False Negative Rate ◽  
Antibody Detection ◽  
Igg Antibodies ◽  
Protein Subunit ◽  
Igg Antibody ◽  
S Protein ◽  
N Protein ◽  
Acute Myocardial Injury

AbstractRapid and accurate tests that detect IgM and IgG antibodies to SARS-CoV-2 proteins are essential in slowing the spread of COVID-19 by identifying patients who are infected with COVID-19. Using a SARS-CoV-2 proteome microarray developed in our lab, we comprehensively profiled both IgM and IgG antibodies in forty patients with early-stage COVID-19, influenza, or non-influenza who had similar symptoms. The results revealed that the SARS-CoV-2 N protein is not an ideal biomarker for COVID-19 diagnosis because of its low immunogenicity, thus tests that rely on this marker alone will have a high false negative rate. Our data further suggest that the S protein subunit 1 receptor binding domain (S1-RBD) might be the optimal antigen for IgM antibody detection, while the S protein extracellular domain (S1+S2ECD) would be the optimal antigen for both IgM and IgG antibody detection. Notably, the combination of all IgM and IgG biomarkers can identify 87% and 73.3% COVID-19 patients, respectively. Finally, the COVID-19-specific antibodies are significantly correlated with the clinical indices of viral infection and acute myocardial injury (p≤0.05). Our data may help understand the function of anti-SARS-CoV-2 antibodies and improve serology tests for rapid COVID-19 screening.

scholarly journals Changes in SARS-CoV-2 Antibody Responses Impact the Estimates of Infections in Population-Based Seroprevalence Studies

2020 ◽  
Author(s):  
Craig Fenwick ◽  
Antony Croxatto ◽  
Alix T. Coste ◽  
Florence Pojer ◽  
Cyril Andre ◽  
...  
Keyword(s):  
General Population ◽  
Acute Infection ◽  
Population Based ◽  
Antibody Responses ◽  
Igg Antibodies ◽  
Rt Pcr ◽  
Igg Antibody ◽  
S Protein ◽  
N Protein ◽  
Total Cohort

We have determined SARS-CoV-2-specific antibody responses in a cohort of 96 individuals with acute infection and in 578 individuals enrolled in a seroprevalence population study in Switzerland including three groups, i.e. subjects with previous RT-PCR confirmed SARS-CoV-2 infections (n=90), positive patient contacts (n=177) and random selected subjects (n=311). SARS-CoV-2 antibody responses specific to the Spike (S), in the monomeric and native trimeric forms, and/or the nucleocapsid (N) proteins were equally sensitive in the acute infection phase. Interestingly, as compared to anti-S antibody responses, those against the N protein appear to wane in the post-infection and substantially underestimated the proportion of SARS-CoV-2 infections in the groups of patient positive contacts, i.e. 10.9 to 32.2% reduction and in the random selected general population, i.e. up to 45% reduction. The overall reduction in seroprevalence targeting only anti-N IgG antibodies for the total cohort ranged from 9.4 to 31%. Of note, the use of the S protein in its native trimer form was more sensitive as compared to monomeric S proteins. These results indicate that the assessment of anti-S IgG antibody responses against the native trimeric S protein should be implemented to estimate SARS-CoV-2 infections in population-based seroprevalence studies.

scholarly journals Severity, Pathogenicity and Transmissibility of Delta and Lambda Variants of SARS-CoV-2, Toxicity of Spike Protein and Possibilities for Future Prevention of COVID-19

2021 ◽  
Vol 9 (10) ◽  
pp. 2167
Author(s):  
Mehrnoosh Moghaddar ◽  
Ramtin Radman ◽  
Ian Macreadie
Keyword(s):  
Neutralizing Antibodies ◽  
Vaccine Development ◽  
World Health ◽  
The Novel ◽  
S Protein ◽  
N Protein ◽  
Novel Variants ◽  
Hotspot Mutations ◽  
Health Organization

The World Health Organization reports that SARS-CoV-2 has infected over 220 million people and claimed over 4.7 million lives globally. While there are new effective vaccines, the differences in behavior of variants are causing challenges in vaccine development or treatment. Here, we discuss Delta, a variant of concern, and Lambda, a variant of interest. They demonstrate high infectivity and are less responsive to the immune response in vaccinated individuals. In this review, we briefly summarize the reason for infectivity and the severity of the novel variants. Delta and Lambda variants exhibit more changes in NSPs proteins and the S protein, compared to the original Wuhan strain. Lambda also has numerous amino acid substitutions in NSPs and S proteins, plus a deletion in the NTD of S protein, leading to partial escape from neutralizing antibodies (NAbs) in vaccinated individuals. We discuss the role of furin protease and the ACE2 receptor in virus infection, hotspot mutations in the S protein, the toxicity of the S protein and the increased pathogenicity of Delta and Lambda variants. We discuss future therapeutic strategies, including those based on high stability of epitopes, conservation of the N protein and the novel intracellular antibody receptor, tripartite-motif protein 21 (TRIM21) recognized by antibodies against the N protein.

scholarly journals Amino Acids 1055 to 1192 in the S2 Region of Severe Acute Respiratory Syndrome Coronavirus S Protein Induce Neutralizing Antibodies: Implications for the Development of Vaccines and Antiviral Agents

2005 ◽  
Vol 79 (6) ◽  
pp. 3289-3296 ◽  
Author(s):  
Choong-Tat Keng ◽  
Aihua Zhang ◽  
Shuo Shen ◽  
Kuo-Ming Lip ◽  
Burtram C. Fielding ◽  
...  
Keyword(s):  
Amino Acids ◽  
Severe Acute Respiratory Syndrome ◽  
Viral Entry ◽  
Neutralizing Antibodies ◽  
Antiviral Agents ◽  
Host Cells ◽  
Heptad Repeat ◽  
Antigenic Determinants ◽  
Amino Acid Residues ◽  
S Protein

ABSTRACT The spike (S) protein of the severe acute respiratory syndrome coronavirus (SARS-CoV) interacts with cellular receptors to mediate membrane fusion, allowing viral entry into host cells; hence it is recognized as the primary target of neutralizing antibodies, and therefore knowledge of antigenic determinants that can elicit neutralizing antibodies could be beneficial for the development of a protective vaccine. Here, we expressed five different fragments of S, covering the entire ectodomain (amino acids 48 to 1192), as glutathione S-transferase fusion proteins in Escherichia coli and used the purified proteins to raise antibodies in rabbits. By Western blot analysis and immunoprecipitation experiments, we showed that all the antibodies are specific and highly sensitive to both the native and denatured forms of the full-length S protein expressed in virus-infected cells and transfected cells, respectively. Indirect immunofluorescence performed on fixed but unpermeabilized cells showed that these antibodies can recognize the mature form of S on the cell surface. All the antibodies were also able to detect the maturation of the 200-kDa form of S to the 210-kDa form by pulse-chase experiments. When the antibodies were tested for their ability to inhibit SARS-CoV propagation in Vero E6 culture, it was found that the anti-SΔ10 antibody, which was targeted to amino acid residues 1029 to 1192 of S, which include heptad repeat 2, has strong neutralizing activities, suggesting that this region of S carries neutralizing epitopes and is very important for virus entry into cells.

scholarly journals Use of a Standardized Bovine Serum Panel To Evaluate a Multiplexed Nonstructural Protein Antibody Assay for Serological Surveillance of Foot-and-Mouth Disease

2007 ◽  
Vol 14 (11) ◽  
pp. 1472-1482 ◽  
Author(s):  
Julie Perkins ◽  
Satya Parida ◽  
Alfonso Clavijo
Keyword(s):  
Nonstructural Protein ◽  
Foot And Mouth Disease ◽  
Mouth Disease ◽  
Enzyme Linked Immunosorbent Assay ◽  
Reference Laboratory ◽  
Additional Information ◽  
Mouth Disease Virus ◽  
Foot And Mouth ◽  
Antibody Assays ◽  
Serological Surveillance

ABSTRACT Liquid array technology has previously been used to show proof of principle of a multiplexed nonstructural protein serological assay to differentiate foot-and-mouth disease virus-infected and vaccinated animals. The current multiplexed assay consists of synthetically produced peptide signatures 3A, 3B, and 3D and the recombinant protein signature 3ABC in combination with four controls. To determine the diagnostic specificity of each signature in the multiplex, the assay was evaluated against a naive population (n = 104) and a vaccinated population (n = 94). Subsequently, the multiplexed assay was assessed by using a panel of bovine sera generated by the World Reference Laboratory for foot-and-mouth disease in Pirbright, United Kingdom. This serum panel has been used to assess the performance of other singleplex enzyme-linked immunosorbent assay (ELISA)-based nonstructural protein antibody assays. The 3ABC signature in the multiplexed assay showed performance comparable to that of a commercially available nonstructural protein 3ABC ELISA (Cedi test), and additional information pertaining to the relative diagnostic sensitivity of each signature in the multiplex was acquired in one experiment. The encouraging results of the evaluation of the multiplexed assay against a panel of diagnostically relevant samples promote further assay development and optimization to generate an assay for routine use in foot-and-mouth disease serological surveillance.

scholarly journals A single immunization with a rhabdovirus-based vector expressing severe acute respiratory syndrome coronavirus (SARS-CoV) S protein results in the production of high levels of SARS-CoV-neutralizing antibodies

2005 ◽  
Vol 86 (5) ◽  
pp. 1435-1440 ◽  
Author(s):  
Milosz Faber ◽  
Elaine W. Lamirande ◽  
Anjeanette Roberts ◽  
Amy B. Rice ◽  
Hilary Koprowski ◽  
...  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Neutralizing Antibodies ◽  
Neutralizing Antibody ◽  
Protein S ◽  
S Protein ◽  
Cellular Immune Responses ◽  
Glycoprotein G ◽  
Cellular Immune ◽  
Animal Reservoirs ◽  
S Genes

Foreign viral proteins expressed by rabies virus (RV) have been shown to induce potent humoral and cellular immune responses in immunized animals. In addition, highly attenuated and, therefore, very safe RV-based vectors have been constructed. Here, an RV-based vaccine vehicle was utilized as a novel vaccine against severe acute respiratory syndrome coronavirus (SARS-CoV). For this approach, the SARS-CoV nucleocapsid protein (N) or envelope spike protein (S) genes were cloned between the RV glycoprotein G and polymerase L genes. Recombinant vectors expressing SARS-CoV N or S protein were recovered and their immunogenicity was studied in mice. A single inoculation with the RV-based vaccine expressing SARS-CoV S protein induced a strong SARS-CoV-neutralizing antibody response. The ability of the RV-SARS-CoV S vector to confer immunity after a single inoculation makes this live vaccine a promising candidate for eradication of SARS-CoV in animal reservoirs, thereby reducing the risk of transmitting the infection to humans.

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