scholarly journals Use of Antibody Avidity Assays for Diagnosis of Severe Acute Respiratory Syndrome Coronavirus Infection

2007 ◽  
Vol 14 (11) ◽  
pp. 1433-1436 ◽  
Author(s):  
K. H. Chan ◽  
K. Sonnenberg ◽  
M. Niedrig ◽  
S. Y. Lam ◽  
C. M. Pang ◽  
...  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Antibody Responses ◽  
High Avidity ◽  
Serum Samples ◽  
Igg Antibody ◽  
Antibody Avidity ◽  
Indirect Immunofluorescent Assay ◽  
Serial Serum ◽  
Coronavirus Infection ◽  
Indirect Immunofluorescent

ABSTRACT An indirect immunofluorescent assay (Euroimmun AG, Luebeck, Germany) was used to investigate the avidity of immunoglobulin G (IgG), IgM, IgA, and total Ig (IgGAM) antibody responses to severe acute respiratory syndrome coronavirus (SARS CoV) infections. Serial serum samples from eight patients collected during the first, third, and ninth months after the onset of infection were evaluated. It was found that low-avidity IgG antibodies were detected in 15/15 (100%), 1/5 (20%), and 0/8 (0%) serum samples collected during the first, third, and ninth months after the onset of symptoms, respectively. Low-avidity antibodies of IgA and IgM subclasses were detected in 14/14 (100%) and 3/14 (21%) serum samples, respectively, collected in the first month after the onset of infection. However, IgA antibodies remained low in avidity in a proportion of patients even during late convalescence. As a consequence, IgG antibody avidity assays gave better discrimination between acute-phase and late-convalescent-phase serum samples than IgM, IgA, or IgGAM assays. In two of these patients, sequential serum samples were also tested for IgG avidity against human CoV strains OC43 and 229E in parallel. While SARS CoV infections induced an anamnestic IgG antibody response to the 229E and OC43 viruses, these cross-reactive antibodies remained of high avidity from early (the first month) postinfection. The results showed that assays to detect low-avidity antibody may be useful for discriminating early from late antibody responses and also for distinguishing anamnestic cross-reactive antibody responses from primary specific responses. This may be useful in some clinical situations.

Importance of the case of coronavirus-associated severe acute respiratory syndrome detected in Hungary in 2005

2013 ◽  
Vol 154 (47) ◽  
pp. 1877-1882
Author(s):  
László Rókusz ◽  
István Jankovics ◽  
Máté Jankovics ◽  
Júlia Sarkadi ◽  
Ildikó Visontai
Keyword(s):  
Middle East ◽  
Severe Acute Respiratory Syndrome ◽  
Unknown Etiology ◽  
Serum Samples ◽  
Igg Antibody ◽  
Remote Areas ◽  
The Past ◽  
The World ◽  
Antibody Positivity ◽  
Coronavirus Infection

Ten years have elapsed since the severe acute respiratory syndrome outbreak, which resulted in more than 8000 cases worldwide with more than 700 deaths. Recently, a new coronavirus, the Middle East Respiratory Syndrome Coronavirus emerged, causing serious respiratory cases and death. By the end of August 2013, 108 cases including 50 deaths were reported. The authors discuss a coronavirus-associated severe acute respiratory syndrome, which was detected in Hungary in 2005 and highlight its significance in 2013. In 2005 the patient was hospitalized and all relevant clinical and microbiological tests were performed. Based on the IgG antibody positivity of the serum samples, the patient was diagnosed as having severe acute respiratory syndrome coronavirus infection in the past. The time and source of the infection remained unknown. The condition of the patient improved and he was discharged from the hospital. The case raises the possibility of infections in Hungary imported from remote areas of the world and the importance of thorough examination of patients with severe respiratory syndrome with unknown etiology. Orv. Hetil., 154(47), 1877–1882.

scholarly journals Long-term persistence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein-specific and neutralizing antibodies in recovered COVID-19 patients

2021 ◽  
Author(s):  
Jira Chansaenroj ◽  
Ritthideach Yorsaeng ◽  
Nasamon Wanlapakorn ◽  
Chintana Chirathaworn ◽  
Natthinee Sudhinaraset ◽  
...  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Symptom Onset ◽  
Neutralizing Antibodies ◽  
Serum Antibody ◽  
Neutralizing Antibody ◽  
Antibody Responses ◽  
Spike Protein ◽  
Immunological Study ◽  
Igg Antibody ◽  
Vaccine Schedule

Abstract Understanding antibody responses after natural severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection can guide the coronavirus disease 2019 (COVID-19) vaccine schedule. This study aimed to assess the dynamics of SARS-CoV-2 antibodies, including anti-spike protein 1 (S1) immunoglobulin (Ig)G, anti-receptor-binding domain (RBD) total Ig, anti-S1 IgA, and neutralizing antibody against wild-type SARS-CoV-2 in a cohort of patients who were previously infected with SARS-CoV-2. Between March and May 2020, 531 individuals with virologically confirmed cases of SARS-CoV-2 infection were enrolled in our immunological study. The neutralizing titers against SARS-CoV-2 were detected in 95.2%, 86.7%, 85.0%, and 85.4% of recovered COVID-19 patients at 3, 6, 9, and 12 months after symptom onset, respectively. The seropositivity rate of anti-S1 IgG, anti-RBD total Ig, anti-S1 IgA, and neutralizing titers remained at 68.6%, 89.6%, 77.1%, and 85.4%, respectively, at 12 months after symptom onset. The half-life of neutralizing titers was estimated at 100.7 days (95% confidence interval = 44.5 – 327.4 days, R2 = 0.106). These results support that the decline in serum antibody levels over time depends on the symptom severity, and the individuals with high IgG antibody titers experienced a significantly longer persistence of SARS-CoV-2-specific antibody responses than those with lower titers.

scholarly journals Longitudinal Analysis of Cryptosporidium Species-Specific Immunoglobulin G Antibody Responses in Peruvian Children

2006 ◽  
Vol 13 (1) ◽  
pp. 123-131 ◽  
Author(s):  
Jeffrey W. Priest ◽  
Caryn Bern ◽  
Lihua Xiao ◽  
Jacquelin M. Roberts ◽  
James P. Kwon ◽  
...  
Keyword(s):  
Immunoglobulin G ◽  
Antibody Responses ◽  
Health Interventions ◽  
Older Children ◽  
Serum Samples ◽  
Igg Antibody ◽  
Specific Immunoglobulin ◽  
Antibody Assays ◽  
Species Specific ◽  
Antibody Levels

ABSTRACT Cryptosporidium species are ubiquitous in the environment and are frequently detected in the stools of children who live where sanitation conditions are poor. To better characterize the immune response to these parasites, we monitored immunoglobulin G (IgG) antibody levels in a cohort of children from Lima, Peru. Two new enzyme-linked immunosorbent assays based on the C. parvum (bovine, subtype IIa) Iowa strain 17-kDa and 27-kDa antigens were used to measure IgG antibody levels in longitudinal serum samples. Antibody responses were detected during infections with C. parvum, C. felis, and C. meleagridis and with four different subtypes of C. hominis. We also noted that the magnitude of the antibody response was related to the number of previous infections and that older children generally had higher levels of antibodies to the two C. parvum antigens. Antibody responses were not associated with infections with either Cyclospora sp. or Giardia sp. We believe the antibody assays will be important tools for monitoring the success of future public health interventions.

scholarly journals Antibody response and viraemia during the course of severe acute respiratory syndrome (SARS)-associated coronavirus infection

2004 ◽  
Vol 53 (5) ◽  
pp. 435-438 ◽  
Author(s):  
Weijun Chen ◽  
Zuyuan Xu ◽  
Jingsong Mu ◽  
Ling Yang ◽  
Haixue Gan ◽  
...  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Antibody Response ◽  
Time Course ◽  
Recovery Phase ◽  
Antibody Responses ◽  
Igg Antibodies ◽  
Rt Pcr ◽  
Blood Samples ◽  
Convalescent Phase ◽  
Coronavirus Infection

To understand the time-course of viraemia and antibody responses to severe acute respiratory syndrome-associated coronavirus (SARS-CoV), RT-PCR and ELISA were used to assay 376 blood samples from 135 SARS patients at various stages of the illness, including samples from patients who were in their early convalescent phase. The results showed that IgM antibodies decreased and became undetectable 11 weeks into the recovery phase. IgG antibodies, however, remained detectable for a period beyond 11 weeks and were found in 100 % of patients in the early convalescent phase. SARS-CoV viraemia mainly appeared 1 week after the onset of illness and then decreased over a period of 1 month, becoming undetectable in the blood samples of the convalescent patients. At the peak of viraemia, viral RNA was detectable in 75 % of blood samples from patients who were clinically diagnosed with SARS 1 or 2 weeks before the test.

scholarly journals Evaluation of Inapparent Nosocomial Severe Acute Respiratory Syndrome Coronavirus Infection in Vietnam by Use of Highly Specific Recombinant Truncated Nucleocapsid Protein-Based Enzyme-Linked Immunosorbent Assay

2005 ◽  
Vol 12 (7) ◽  
pp. 848-854 ◽  
Author(s):  
Fuxun Yu ◽  
Mai Quynh Le ◽  
Shingo Inoue ◽  
Hong Thi Cam Thai ◽  
Futoshi Hasebe ◽  
...  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Large Scale ◽  
Screening Method ◽  
Epidemiological Studies ◽  
Enzyme Linked Immunosorbent Assay ◽  
Serum Samples ◽  
Nucleocapsid Proteins ◽  
N Protein ◽  
Care Workers ◽  
Coronavirus Infection

ABSTRACT Severe acute respiratory syndrome (SARS) is a recently emerged human disease associated with pneumonia. Inapparent infection with SARS coronavirus (CoV) is not well characterized. To develop a safe, simple, and reliable screening method for SARS diagnosis and epidemiological study, two recombinant SARS-CoV nucleocapsid proteins (N′ protein and NΔ121 protein) were expressed in Escherichia coli, purified by affinity chromatography, and used as antigens for indirect, immunoglobulin G enzyme-linked immunosorbent assays (ELISA). Serum samples collected from healthy volunteers and SARS patients in Vietnam were used to evaluate the newly developed methods. The N′ protein-based ELISA showed a highly nonspecific reaction. The NΔ121 protein-based ELISA, with a nonspecific reaction drastically reduced compared to that of the nearly-whole-length N′ protein-based ELISA, resulted in higher rates of positive reactions, higher titers, and earlier detection than the SARS-CoV-infected cell lysate-based ELISA. These results indicate that our newly developed SARS-CoV NΔ121 protein-based ELISA is not only safe but also a more specific and more sensitive method to diagnose SARS-CoV infection and hence a useful tool for large-scale epidemiological studies. To identify inapparent SARS-CoV infections, serum samples collected from health care workers (HCWs) in Vietnam were screened by the NΔ121 protein-based ELISA, and positive samples were confirmed by a virus neutralization test. Four out of 149 HCWs were identified to have inapparent SARS-CoV infection in Vietnam, indicating that subclinical SARS-CoV infection in Vietnam is rare but does exist.

scholarly journals A Modified Enzyme-Linked Immunosorbent Assay for Measurement of Antibody Responses to Meningococcal C Polysaccharide That Correlate with Bactericidal Responses

1998 ◽  
Vol 5 (4) ◽  
pp. 479-485 ◽  
Author(s):  
Dan M. Granoff ◽  
Susan E. Maslanka ◽  
George M. Carlone ◽  
Brian D. Plikaytis ◽  
George F. Santos ◽  
...  
Keyword(s):  
Immunosorbent Assay ◽  
Geometric Mean ◽  
Correlation Coefficients ◽  
Antibody Responses ◽  
Enzyme Linked Immunosorbent Assay ◽  
High Avidity ◽  
Igg Antibody ◽  
Standard Assay ◽  
Bactericidal Antibody ◽  
Antibody Titers

ABSTRACT The standardized enzyme-linked immunosorbent assay (ELISA) for measurement of serum immunoglobulin G (IgG) antibody responses to meningococcal C polysaccharide has been modified to employ assay conditions that ensure specificity and favor detection primarily of high-avidity antibodies. The modified and standard assays were used to measure IgG antibody concentrations in sera of toddlers vaccinated with meningococcal polysaccharide vaccine or a meningococcal C conjugate vaccine. The results were compared to the respective complement-mediated bactericidal antibody titers. In sera obtained after one or two doses of vaccine, the correlation coefficients, r, for the results of the standard assay and bactericidal antibody titers were 0.45 and 0.29, compared to 0.85 and 0.87, respectively, for the modified assay. With the standard assay, there were no significant differences between the geometric mean antibody responses of the two vaccine groups. In contrast, with the modified assay, 5- to 20-fold higher postvaccination antibody concentrations were measured in the conjugate than in the polysaccharide group. Importantly, the results of the modified assay, but not the standard ELISA, paralleled the respective geometric mean bactericidal antibody titers. Thus, by employing conditions that favor detection of higher-avidity IgG antibody, the modified ELISA provides results that correlate closely with measurements of antibody functional activity that are thought to be important in protection against meningococcal disease.

scholarly journals COMPARISON OF PERFORMANCE CHARACTERISTICS BETWEEN LATERAL FLOW, ELISA AND ELECTROCHEMILUMINESCENCE IMMUNOASSAYS FOR THE DETECTION OF SARS-COV-2 ANTIBODIES AMONG HEALTHCARE WORKERS

2021 ◽  
Author(s):  
M R Shincy ◽  
Vandana Govindan ◽  
H H Sudhakar ◽  
V T Venkatesha ◽  
K Padmapriya ◽  
...  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Healthcare Workers ◽  
Care Pathway ◽  
Point Of Care ◽  
Lateral Flow ◽  
Central Research ◽  
Serum Samples ◽  
Igg Antibody ◽  
Human Igg ◽  
Serological Tests

ABSTRACTBackgroundMedical professionals and researchers have been urging the need for wide and rapid testing of citizens in order to plan measures that can contain the spread of the virus. Antibody tests play an important role throughout the patient care pathway and are vital for the management and surveillance of the virus. Although RT-PCR is considered as the gold standard, serological tests based on antibodies are helpful for on-time detection. We performed one to one assessment of point-of-care lateral flow assay (POCTs), enzyme immunoassay (EIAs), electrochemiluminescence immunoassay (CLIA), to detect severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) IgG antibody.Materials and Methods611 healthcare workers were recruited between November and December 2020 at Central Research Laboratory, KIMS. Collected serum samples were analysed according to manufacturer’s protocol. The Standard Q IgG/IgM combo assay, Anti-SARS CoV-2 Human IgG ELISA, and the Elecsys® to measure the IgG titer of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).ResultsThe kits displayed a sensitivity of 61.2%,79.5%, 91.8% and specificity of 61.7%,64.1%,80.2% for the Standard Q IgG/IgM combo assay, Anti-SARS CoV-2 Human IgG ELISA, and the Elecsys® in order.ConclusionOur results indicate high sensitivity and specificity for the Elecsys® assay compared to Anti-SARS CoV-2 Human IgG ELISA, the Standard Q IgG/IgM combo assay.

scholarly journals Evaluating the serological status of COVID-19 patients using an indirect immunofluorescent assay, France

2020 ◽  
Author(s):  
S. Edouard ◽  
P. Colson ◽  
C. Melenotte ◽  
F. De Pinto ◽  
L. Thomas ◽  
...  
Keyword(s):  
Therapeutic Option ◽  
Serum Samples ◽  
Positive Serology ◽  
Immunofluorescent Assay ◽  
Indirect Immunofluorescent Assay ◽  
Serological Status ◽  
Favourable Evolution ◽  
The Individual ◽  
Negative Controls ◽  
Indirect Immunofluorescent

ABSTRACTAn indirect immunofluorescent assay was developed in order to assess the serological status of 888 RT-PCR-confirmed COVID-19 patients (1,302 serum samples) and controls in Marseille, France. Incorporating an inactivated clinical SARS CoV-2 isolate as the antigen, the specificity of the assay was measured as 100% for IgA titre ≥ 1:200; 98.6% for IgM titre ≥ 1:200; and 96.3% for IgG titre ≥ 1:100 after testing a series of negative controls as well as 150 serums collected from patients with non-SARS-CoV-2 Coronavirus infection, non-Coronavirus pneumonia and infections known to elicit false-positive serology. Seroprevalence was then measured at 3% before a five-day evolution up to 47% after more than 15 days of evolution. We observed that the seroprevalence as well as the titre of specific antibodies were both significantly higher in patients with a poor clinical outcome than in patients with a favourable evolution. These data, which have to be integrated into the ongoing understanding of the immunological phase of the infection, suggest that serotherapy may not be a therapeutic option in patients with severe COVID-19 infection. The IFA assay reported here is useful for monitoring SARS-CoV-2 exposure at the individual and population levels.

scholarly journals Serological signatures of SARS-CoV-2 infection: Implications for antibody-based diagnostics

2020 ◽  
Author(s):  
Jason Rosado ◽  
Stéphane Pelleau ◽  
Charlotte Cockram ◽  
Sarah Hélène Merkling ◽  
Narimane Nekkab ◽  
...  
Keyword(s):  
Population Level ◽  
Classification Performance ◽  
Negative Control ◽  
Antibody Responses ◽  
Serum Samples ◽  
Igg Antibody ◽  
Low Transmission ◽  
Control Serum ◽  
Challenges And Opportunities ◽  
Serological Diagnostics

AbstractBackgroundInfection with SARS-CoV-2 induces an antibody response targeting multiple antigens that changes over time. This complexity presents challenges and opportunities for serological diagnostics.MethodsA multiplex serological assay was developed to measure IgG and IgM antibody responses to seven SARS-CoV-2 spike or nucleoprotein antigens, two antigens for the nucleoproteins of the 229E and NL63 seasonal coronaviruses, and three non-coronavirus antigens. Antibodies were measured in serum samples from patients in French hospitals with RT-qPCR confirmed SARS-CoV-2 infection (n = 259), and negative control serum samples collected before the start of the SARS-CoV-2 epidemic (n = 335). A random forests algorithm was trained with the multiplex data to classify individuals with previous SARS-CoV-2 infection. A mathematical model of antibody kinetics informed by prior information from other coronaviruses was used to estimate time-varying antibody responses and assess the potential sensitivity and classification performance of serological diagnostics during the first year following symptom onset. A statistical estimator is presented that can provide estimates of seroprevalence in very low transmission settings.ResultsIgG antibody responses to trimeric Spike protein identified individuals with previous RT-qPCR confirmed SARS-CoV-2 infection with 91.6% sensitivity (95% confidence interval (CI); 87.5%, 94.5%) and 99.1% specificity (95% CI; 97.4%, 99.7%). Using a serological signature of IgG and IgM to multiple antigens, it was possible to identify infected individuals with 98.8% sensitivity (95% CI; 96.5%, 99.6%) and 99.3% specificity (95% CI; 97.6%, 99.8%). Informed by prior data from other coronaviruses, we estimate that one year following infection a monoplex assay with optimal anti-Stri IgG cutoff has 88.7% sensitivity (95% CI: 63.4%, 97.4%), and that a multiplex assay can increase sensitivity to 96.4% (95% CI: 80.9%, 100.0%). When applied to population-level serological surveys, statistical analysis of multiplex data allows estimation of seroprevalence levels less than 1%, below the false positivity rate of many other assays.ConclusionSerological signatures based on antibody responses to multiple antigens can provide accurate and robust serological classification of individuals with previous SARS-CoV-2 infection. This provides potential solutions to two pressing challenges for SARS-CoV-2 serological surveillance: classifying individuals who were infected greater than six months ago, and measuring seroprevalence in serological surveys in very low transmission settings.

scholarly journals SARS-CoV-2 IgG antibody responses in rt-PCR positive cases: first report from India

2020 ◽  
Author(s):  
Girish Chandra Dash ◽  
Debaprasad Parai ◽  
Hari Ram Choudhary ◽  
Annalisha Peter ◽  
Usha Kiran Rout ◽  
...  
Keyword(s):  
Antibody Response ◽  
Infected Individual ◽  
Antibody Responses ◽  
Rt Pcr ◽  
Serum Samples ◽  
Igg Antibody ◽  
Ct Value ◽  
Significant Difference ◽  
The Mean ◽  
The Relationship

AbstractThe SARS-CoV-2 antibody responses remain poorly understood and the clinical utility of serological testing is still unclear. As it is thought to confer some degree of immunity, this study is carried out to know the relationship between demographics and ct value of confirmed rt-PCR patients. A total of 384 serum samples were collected between 4-6 weeks after confirmed SARS-CoV-2 infection. IgG positivity was found to be 80.2% (95% CI, 76.2 – 84.2). The IgG positivity increased with the decrease in the ct value, with highest of 87.6% positivity in individuals with <20 ct value. The mean (± SD) ct value of IgG positives and og IgG negatives was 23.34 (± 6.09) and 26.72 (± 7.031) respectively. There was no significant difference found between the demographic characteristics such as age, sex, symptoms and antibody response. The current study is first of its kind wherein we have assessed the correlation of ct of RT-PCR with development of IgG against SARS-CoV-2. Our study showed that although Ct value might not have any relation with severity of the diseases but is associated with the antibody response among the SARS-CoV-2 infected individual.

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