scholarly journals Comparative analysis of antigen-specific anti-SARS-CoV-2 antibody isotypes in COVID-19 patients

2020 ◽  
Author(s):  
Hidetsugu Fujigaki ◽  
Masato Inaba ◽  
Michiko Osawa ◽  
Saya Moriyama ◽  
Yoshimasa Takahashi ◽  
...  
Keyword(s):  
Specific Antibody ◽  
Serological Test ◽  
Polymerase Chain Reaction Test ◽  
Enzyme Linked Immunosorbent Assay ◽  
Serological Tests ◽  
S Protein ◽  
Neutralizing Activity ◽  
N Protein ◽  
Specificity And Sensitivity ◽  
Antibody Isotypes

AbstractSerological tests for detection of anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies in blood are expected to identify individuals who have acquired immunity against SARS-CoV-2 and indication of seroprevalence of SARS-CoV-2 infection. Many serological tests have been developed to detect antibodies against SARS-CoV-2. However, these tests have considerable variations in their specificity and sensitivity, and whether they can predict levels of neutralizing activity is yet to be determined. This study aimed to investigate the kinetics and neutralizing activity of various antigen-specific antibody isotypes against SARS-CoV-2 in serum of coronavirus disease 2019 (COVID-19) patients confirmed via polymerase chain reaction test. We developed IgG, IgM and IgA measurement assays for each antigen, including receptor-binding domain (RBD) of spike (S) protein, S1 domain, full length S protein, S trimer and nucleocapsid (N) domain, based on enzyme-linked immunosorbent assay. The assays of the S protein for all isotypes showed high specificity, while the assays for all isotypes against N protein showed lower specificity. The sensitivity of all antigen-specific antibody isotypes depended on the timing of the serum collection and all of them, except for IgM against N protein, reached more than 90% at 15-21 days post-symptom onset. The best correlation with virus neutralizing activity was found for IgG against RBD (RBD-IgG), and levels of RBD-IgG in sera from four severe COVID-19 patients increased concordantly with neutralizing activity. Our results provide valuable information regarding the selection of serological test for seroprevalence and vaccine evaluation studies.

scholarly journals Increased detection of schistosomiasis with Kato-Katz and SWAP-IgG-ELISA in a Northeastern Brazil low-intensity transmission area

2012 ◽  
Vol 45 (4) ◽  
pp. 510-513 ◽  
Author(s):  
Teiliane Rodrigues Carneiro ◽  
Marta Cristhiany Cunha Pinheiro ◽  
Sara Menezes de Oliveira ◽  
Ana Lúcia de Paula Hanemann ◽  
José Ajax Nogueira Queiroz ◽  
...  
Keyword(s):  
Serological Test ◽  
Laboratory Diagnosis ◽  
Elisa Test ◽  
Northeastern Brazil ◽  
Enzyme Linked Immunosorbent Assay ◽  
Serological Tests ◽  
Predictive Values ◽  
Transmission Area ◽  
Elisa Technique ◽  
Endemic Areas

INTRODUCTION: The laboratory diagnosis of schistosomiasis is based mainly on the detection of parasite eggs in stool samples through the Kato-Katz (KK) technique, reading one slide by test. However, a widely known limitation of parasitological methods is reduced sensitivity, particularly in low endemic areas. METHODS: To increase sensitivity, we conducted further slide readings from the same stool sample using the parasitological method associated with a serological test. We used the KK method (three slides) and the IgG anti-Schistosoma mansoni-enzyme-linked immunosorbent assay (ELISA) technique to diagnose schistosomiasis in low endemic areas in the Brazilian State of Ceará. Fecal samples and sera from 250 individuals were analyzed. RESULTS: Sixteen percent and 47.2% of samples were positive in parasitological tests and serological tests, respectively. Parasitological methods showed that 32 (80%) individuals tested positive on the first slide, 6 (15%) on the second slide, and 2 (5%) on the third. The performance of the ELISA test in the diagnosis, using the KK method as diagnostic reference, showed a negative predictive value of 100%, with specificity and positive predictive values of 62.8% and 33.9%, respectively. CONCLUSIONS: In this study, the increase from one to three slides analyzed per sample using the KK technique was shown to be a useful procedure for increasing the diagnostic sensitivity of this technique.

scholarly journals Serodiagnosis of Louse-Borne Relapsing Fever with Glycerophosphodiester Phosphodiesterase (GlpQ) fromBorrelia recurrentis

2000 ◽  
Vol 38 (10) ◽  
pp. 3561-3571 ◽  
Author(s):  
Stephen F. Porcella ◽  
Sandra J. Raffel ◽  
Merry E. Schrumpf ◽  
Martin E. Schriefer ◽  
David T. Dennis ◽  
...  
Keyword(s):  
Serological Test ◽  
Geometric Mean ◽  
Eastern Africa ◽  
Enzyme Linked Immunosorbent Assay ◽  
Relapsing Fever ◽  
Serum Samples ◽  
Serological Tests ◽  
Whole Cell ◽  
Convalescent Phase ◽  
Glycerophosphodiester Phosphodiesterase

Human louse-borne relapsing fever occurs in sporadic outbreaks in central and eastern Africa that are characterized by significant morbidity and mortality. Isolates of the causative agent,Borrelia recurrentis, were obtained from the blood of four patients during a recent epidemic of the disease in southern Sudan. TheglpQ gene, encoding glycerophosphodiester phosphodiesterase, from these isolates was sequenced and compared with the glpQ sequences obtained from other relapsing-fever spirochetes. Previously we showed that GlpQ of Borrelia hermsii is an immunogenic protein with utility as a serological test antigen for discriminating tick-borne relapsing fever from Lyme disease. In the present work, we cloned and expressed theglpQ gene from B. recurrentis and used recombinant GlpQ in serological tests. Acute- and convalescent-phase serum samples obtained from 42 patients with louse-borne relapsing fever were tested with an indirect immunofluorescence assay (IFA) and an enzyme-linked immunosorbent assay (ELISA) that used whole cells ofB. recurrentis and with immunoblotting to whole-cell lysates of the spirochete and Escherichia coli producing recombinant GlpQ. The geometric mean titers of the acute- and convalescent-phase serum samples measured by IFA were 1:83 and 1:575, respectively. The immunoblot analysis identified a high level of reactivity and seroconversion to GlpQ, and the assay was more sensitive than the whole-cell IFA and ELISA using purified, recombinant histidine-tagged GlpQ. Serum antibodies to GlpQ and other antigens persisted for 27 years in one patient. We conclude that assessment of anti-GlpQ antibodies will allow serological confirmation of louse-borne relapsing fever and determination of disease prevalence.

scholarly journals An enzyme-linked immunosorbent assay for the detection of IgG antibodies against Babesia equi in horses

2004 ◽  
Vol 34 (5) ◽  
pp. 1525-1529 ◽  
Author(s):  
Cristiane Divan Baldani ◽  
Rosangela Zacarias Machado ◽  
Paulo de Tarso Landgraf Botteon ◽  
Felipe Santoro Takakura ◽  
Carlos Luiz Massard
Keyword(s):  
Immunosorbent Assay ◽  
Serological Test ◽  
Epidemiological Studies ◽  
Sao Paulo ◽  
Enzyme Linked Immunosorbent Assay ◽  
São Paulo ◽  
Igg Antibodies ◽  
Serum Samples ◽  
Babesia Equi ◽  
Specificity And Sensitivity

A crude antigenic preparation of Babesia equi was used to develop and establish the suitability of an enzyme-linked immunosorbent assay (ELISA) for the detection of parasite carriers. Optimal dilutions of the antigen, using positive and negative reference sera, were determined by checkboard titrations. The specificity and sensitivity of the ELISA were 100 %. A total of 90 serum samples were taken from horses from the Northeast region of São Paulo State and examined for diagnosis of equine B. equi infection by ELISA. Approximately 75% (n=67) of all the horses tested were found serologically positive for B. equi. These results suggest that the ELISA described may prove to be an appropriate serological test for epidemiological studies on B. equi infections in the field and that equine piroplasmosis is a cause for serious concern in the State of São Paulo, Brazil.

scholarly journals SARS-CoV-2 S1 and N-based serological assays reveal rapid seroconversion and induction of specific antibody response in COVID-19 patients

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Abdullah Algaissi ◽  
Mohamed A. Alfaleh ◽  
Sharif Hala ◽  
Turki S. Abujamel ◽  
Sawsan S. Alamri ◽  
...  
Keyword(s):  
Antibody Response ◽  
Specific Antibody ◽  
Large Scale ◽  
Disease Onset ◽  
High Specificity ◽  
Epidemiological Studies ◽  
Cross Reactivity ◽  
Enzyme Linked Immunosorbent Assay ◽  
Specificity And Sensitivity ◽  
Human Coronaviruses

Abstract As the Coronavirus Disease 2019 (COVID-19), which is caused by the novel SARS-CoV-2, continues to spread rapidly around the world, there is a need for well validated serological assays that allow the detection of viral specific antibody responses in COVID-19 patients or recovered individuals. In this study, we established and used multiple indirect Enzyme Linked Immunosorbent Assay (ELISA)-based serological assays to study the antibody response in COVID-19 patients. In order to validate the assays we determined the cut off values, sensitivity and specificity of the assays using sera collected from pre-pandemic healthy controls, COVID-19 patients at different time points after disease-onset, and seropositive sera to other human coronaviruses (CoVs). The developed SARS-CoV-2 S1 subunit of the spike glycoprotein and nucleocapsid (N)-based ELISAs not only showed high specificity and sensitivity but also did not show any cross-reactivity with other CoVs. We also show that all RT-PCR confirmed COVID-19 patients tested in our study developed both virus specific IgM and IgG antibodies as early as week one after disease onset. Our data also suggest that the inclusion of both S1 and N in serological testing would capture as many potential SARS-CoV-2 positive cases as possible than using any of them alone. This is specifically important for tracing contacts and cases and conducting large-scale epidemiological studies to understand the true extent of virus spread in populations.

scholarly journals Laboratory Confirmation of Lyme Disease

1991 ◽  
Vol 2 (2) ◽  
pp. 64-69 ◽  
Author(s):  
Tom G Schwan ◽  
Warren J Simpson ◽  
Patricia A Rosa
Keyword(s):  
Lyme Disease ◽  
Immunofluorescence Assay ◽  
Detection Methods ◽  
Enzyme Linked Immunosorbent Assay ◽  
Serological Tests ◽  
Specificity And Sensitivity ◽  
Laboratory Confirmation ◽  
Staining Methods ◽  
Alternative Detection ◽  
Species Specific

Lyme disease can be confirmed in the laboratory by isolation or detection of its causative agent, a tick-borne spirocheteBorrelia burgdorferi,or by a diagnostic change in the titre of antibodies specific to the agent.B burgdorferican be isolated and cultivated in Barbour-Stoenner-Kelly II medium. It can be detected by light microscopy in tissue sections or, rarely, in blood smears using various staining methods. There is interest in the development of alternative detection methods, including identification of specific antigens ofB burgdorferiin the urine of suspected cases and demonstration of the presence of species-specific DNA using polymerase chain reaction assays. Currently, serological tests (indirect immunofluorescence assay, enzyme-linked immunosorbent assay and Western immunoblot) are the most practical and available methods for confirming Lyme disease. The quest to improve the specificity and sensitivity of serological tests – for example, through the use of specific recombinant antigens – continues.

scholarly journals Expression of the Nucleoprotein of the Puumala Virus from the Recombinant Semliki Forest Virus Replicon: Characterization and Use as a Potential Diagnostic Tool

2003 ◽  
Vol 10 (4) ◽  
pp. 658-663 ◽  
Author(s):  
A. Billecocq ◽  
D. Coudrier ◽  
F. Boué ◽  
B. Combes ◽  
H. Zeller ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Semliki Forest Virus ◽  
Immunoglobulin M ◽  
Enzyme Linked Immunosorbent Assay ◽  
Puumala Virus ◽  
Wild Rodents ◽  
Serological Tests ◽  
N Protein ◽  
Antigenic Properties ◽  
Native Antigen

ABSTRACT Puumala virus (Bunyaviridae family, Hantavirus genus) causes a mild form of hemorrhagic fever with renal syndrome (HFRS) called nephropathia epidemica in northern and central Europe. Serological tests are used for diagnosis, but antigen production is difficult because the virus grows poorly in tissue culture. We expressed the N protein (nucleoprotein) of Puumala virus via the Semliki Forest virus (SFV) replicon in mammalian cells and compared its antigenic properties with those of the native antigen derived from Puumala virus-infected cells. Detection of immunoglobulin G or immunoglobulin M by enzyme-linked immunosorbent assay (ELISA), μ-capture ELISA, and indirect immunofluorescence assay was (at least) as effective with the recombinant antigen as with the native antigen when HFRS patient sera or organ washes from wild rodents were tested. No nonspecific reaction was observed. Thus, the SFV-expressed N protein of Puumala virus appears as a valid antigen, specific and sensitive for serological investigations.

scholarly journals Recombinant Truncated Flagellin of Burkholderia pseudomallei as a Molecular Probe for Diagnosis of Melioidosis

2003 ◽  
Vol 10 (3) ◽  
pp. 423-425 ◽  
Author(s):  
Yao-Shen Chen ◽  
David Shiuan ◽  
Ssu-Ching Chen ◽  
Soi-Moi Chye ◽  
Ya-Lei Chen
Keyword(s):  
Burkholderia Pseudomallei ◽  
Indirect Elisa ◽  
Full Length ◽  
Detection Sensitivity ◽  
Molecular Probe ◽  
Enzyme Linked Immunosorbent Assay ◽  
False Positive Result ◽  
Serological Tests ◽  
Specificity And Sensitivity ◽  
Detection Specificity

ABSTRACT Current serological tests for melioidosis, using impure or uncharacterized cell antigens from Burkholderia pseudomallei, have problems in detection sensitivity and specificity. Therefore, we designed and expressed the recombinant flagellin (truncated at both the N- and C-terminal ends), and used the antigen to develop an indirect enzyme-linked immunosorbent assay (ELISA) to diagnose melioidosis. Comparison of the immunoreactivities of the full-length and truncated flagellins reveals that the truncated flagellin performed much better in detection specificity and sensitivity. Only the full-length flagellin was recognized by other bacterial causing septicemia and gave a false-positive result in Western analysis, indicating that the cross-reactive epitopes were located on the more highly conserved N- and C-terminal regions of flagellin. The indirect ELISA using recombinant truncated flagellin as the antigen achieved 93.8% sensitivity and 96.3% specificity and offered a more efficient serodiagnosis of melioidosis.

scholarly journals SARS-CoV-2 S1 and N-Based Serological Assays Reveal Rapid Seroconversion and Induction of Specific Antibody Response in COVID-19 Patients

2020 ◽  
Author(s):  
Abdullah Algaissi ◽  
Mohamed A. Alfaleh ◽  
Sherif Hala ◽  
Turki S. Abujamel ◽  
Sawsan S. Alamri ◽  
...  
Keyword(s):  
Antibody Response ◽  
Specific Antibody ◽  
Large Scale ◽  
Disease Onset ◽  
High Specificity ◽  
Epidemiological Studies ◽  
Cross Reactivity ◽  
Enzyme Linked Immunosorbent Assay ◽  
Specificity And Sensitivity ◽  
Human Coronaviruses

As the coronavirus disease 2019 (COVID-19), which is caused by the novel SARS-CoV-2, continues to spread rapidly around the world, there is a need for well validated serological assays that allow the detection of viral specific antibody responses in COVID-19 patients or recovered individuals. In this study, we established and used multiple indirect Enzyme Linked Immunosorbent Assay (ELISA)-based serological assays to study the antibody response in COVID-19 patients. In order to validate the assays we determined the cut off values, sensitivity and specificity of the assays using sera collected from pre-pandemic healthy controls, COVID-19 patients at different time points after disease-onset, and seropositive sera to other human coronaviruses. The developed SARS-CoV-2 S1 subunit of the spike glycoprotein and nucleocapsid (N)-based ELISAs not only showed high specificity and sensitivity but also did not show any cross-reactivity with other CoVs. We also show that all RT-PCR confirmed COVID-19 patients tested in our study developed both virus specific IgM and IgG antibodies as early as week one after disease onset. Our data also suggest that the inclusion of both S1 and N in serological testing would capture as many potential SARS-CoV-2 positive cases as possible than using any of them alone. This is specifically important for tracing contacts and cases and conducting large-scale epidemiological studies to understand the true extent of virus spread in populations.

scholarly journals Diagnostic Accuracy of COVID-19 Antibody Tests Authorized by FDA Philippines: A Systematic Review and Meta-Analysis

2021 ◽  
Vol 3 (4) ◽  
pp. 283-301
Author(s):  
Carmel Reina R. Chua ◽  
Esther Delle E. De los Santos ◽  
Karla Veronica H. Escasa ◽  
Richmond Louis G. Estolas ◽  
Junnealyn Feliciano ◽  
...  
Keyword(s):  
Systematic Review ◽  
Diagnostic Accuracy ◽  
Random Effects ◽  
Meta Analysis ◽  
Characteristic Curve ◽  
Enzyme Linked Immunosorbent Assay ◽  
Serological Tests ◽  
Random Effects Models ◽  
Specificity And Sensitivity ◽  
Antibody Tests

Introduction: Coronavirus Disease (COVID-19) is a highly infectious disease caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) which has infected many people all over the world. One of the best ways to lessen its spread is through early detection and diagnosis. Various serological tests are now being used as a surveillance tool in the detection of antibodies as a response to SARS-CoV-2. The aim of this study is to evaluate the diagnostic accuracy and performance of the available COVID-19 antibody tests authorized by the Food and Drug Administration (FDA) Philippines that make use of Enzyme-Linked Immunosorbent Assay (ELISA), Chemiluminescence Immunoassay (CLIA) and Lateral Flow Immunoassay (LFIA). Method: Complete published journal articles relevant to the diagnostic accuracy of the three antibody tests were collected using trusted medical journal search engines. The quality of journals was assessed using QUADAS-2 to determine the risk of bias and assess the applicability judgments of diagnostic accuracy studies. Forest plots were used to summarize the performance of LFIA, ELISA and CLIA according to their specificity and sensitivity in detecting various antibodies. Pooled sensitivity and specificity were also done using bivariate random-effects models with its log-likelihood, a corresponding chi-square test statistic, and area under the summary Receiver-Operating Characteristic curve to see the potential heterogeneity in the data and to assess the diagnostic accuracy of the COVID-19 antibody tests. Results: Bivariate random-effects model and areas under the sROC curve were used to evaluate the diagnostic accuracy of COVID-19 antibody tests. The pooled sensitivity in detecting IgG based on CLIA, ELISA, and LFIA were 81.7%, 58.7%, and 74.3% respectively, with an overall of 72.0%. For IgM detection, LFIA has a higher pooled sensitivity of 69.6% than CLIA with 61.0%. Overall, the pooled sensitivity is 68.5%. In IgA detection, only ELISA based test was included with a pooled sensitivity of 84.8%. Lastly, pooled sensitivities for combined antibodies based on ELISA and LFIA were 89.0% and 81.6% respectively, with an overall of 82.5%. On the other hand, all tests excluding ELISA-IgA displayed high pooled specificities with a range of 94.0% to 100.0%. Diagnostic accuracies of the test in detecting IgG, IgM, and combined antibodies were found out to be almost perfect based on the computed area under the sROC with values of 0.973, 0.953, and 0.966, respectively. Conclusion: In this systematic review and meta-analysis, existing evidence on the diagnostic accuracy of antibody tests for COVID-19 were found to be characterized by high risks of bias, consistency in the heterogeneity of sensitivities, and consistency in the homogeneity of high specificities except in IgA detection using ELISA. The bivariate random-effects models showed that there are no significant differences in terms of sensitivity among CLIA, ELISA and LFIA in detecting IgG, IgM, and combined antibodies at a 95% confidence interval. Nonetheless, CLIA, ELISA and LFIA were found to have excellent diagnostic accuracies in the detection of IgG, IgM and combined antibodies as reflected by their AUC values. Doi: 10.28991/SciMedJ-2021-0304-1 Full Text: PDF

scholarly journals Expression and novel alternative purification of the recombinant nucleocapsid (N) protein of SARS-CoV-2 in Escherichia coli for the serodiagnosis of COVID-19

2021 ◽  
Author(s):  
Jose David Rosales ◽  
William Quintero ◽  
Jhon Cruz ◽  
Balbino Perdomo ◽  
Militza Quintero ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Protein S ◽  
Exchange Chromatography ◽  
Diagnostic Methods ◽  
Enzyme Linked Immunosorbent Assay ◽  
Metal Exchange ◽  
Serological Tests ◽  
N Protein ◽  
Global Pandemic ◽  
Novel Strategy

The SARS-CoV-2 coronavirus causes severe acute respiratory syndrome and has caused a global pandemic by causing the COVID-19 disease. To monitor and control it, diagnostic methods such as molecular and serological tests are necessary. The serological approach use SARS-CoV-2 antigens to detect the antibodies present in patients using quantitative techniques such as enzyme-linked immunosorbent assay (ELISA) or qualitative rapid tests such as lateral flow chromatography (RDT's). The main antigens used are the spike protein (S) and the nucleocapsid protein (N). Both proteins are obtained in different expression systems, in eukaryotic cells, their production is expensive, so in this work we chose a simpler and cheaper system such as prokaryotic to express and purify the N protein. Thereore, the nucleotide sequence had to being optimized to be expressed in Escherichia coli. The protein N is sensitive to E.coli proteases and also has the ability to self-proteolyze under native conditions, degrading into different fragments. However, under denaturing conditions, using urea and at pH 5.3 it is stable and efficiently purified using metal exchange chromatography (IMAC). In our purification strategy, we surprisingly found that by not using a sonicator, a homogeneous and time-stable preparation of the recombinant antigen is obtained. An approximate yield of 200 mg / L was obtained. It was then tested with healthy sera and sera from COVID-19 convalescent patients in Wester-blot tests that were able to recognize it. Our work provides a novel strategy to produce the SARS-CoV-2 protein N so that it can be used as an input in the development and innovation of serological tests in the diagnosis of COVID-19.

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