scholarly journals IgG antibody response against Nucleocapsid and Spike protein post SARS-CoV-2 infection

2021 ◽  
Author(s):  
Hari Ram Choudhary ◽  
Debaprasad Parai ◽  
Girish Chandra Dash ◽  
Annalisha Peter ◽  
Subrat Kumar Sahoo ◽  
...  
Keyword(s):  
Spike Protein ◽  
Complete Disappearance ◽  
Serum Samples ◽  
Igg Antibody ◽  
Observational Cohort ◽  
Public Health Challenge ◽  
Qualitative Assay ◽  
Polymerase Chain ◽  
Abbott Architect

Abstract Objectives: Coronavirus disease-19 (COVID-19) pandemic became the greatest public health challenge globally. Study of dynamicity and durability of naturally developed antibodies against SARS-CoV-2 are of great importance from an epidemiological viewpoint.Methods: In this observational cohort study, we have followed up the 76 individuals who tested positive for SARS-CoV-2 infection by real-time reverse transcriptase-polymerase chain reaction (RT-qPCR) for 16 weeks (post enrollment) to record the periodic changes in titre, concentration, clinical growth and persistence of naturally developed SARS-CoV-2 antibodies. We collected serum samples from these individuals for 16 weeks with a frequency of weekly and fortnightly during each follow-up and tested them in two CLIA-based platforms (Abbott Architect i1000SR and Roche Cobas e411) for testing SARS-CoV-2 antibodies both qualitatively and quantitatively.Results: We recorded the antibody magnitude of these individuals 10 times between September 2020 and February 2021. We found a waning of antibodies against nucleocapsid antigen protein but not a complete disappearance by the end of 16 weeks. Out of 76 cases, 30 cases (39.47%) became seronegative in qualitative assay, although all the sera samples (100%) remained positive when tested in quantitative assay.Conclusion: The lower persistence of anti-nucleocapsid SARS-CoV-2 antibody may not be the exact phenomenon as those cases were still seropositive against spike protein and help in neutralizing the virus.

scholarly journals Detection of SARS-CoV-2 IgG Targeting Nucleocapsid or Spike Protein by Four High-Throughput Immunoassays Authorized for Emergency Use

2020 ◽  
Vol 58 (11) ◽  
Author(s):  
Harry E. Prince ◽  
Tara S. Givens ◽  
Mary Lapé-Nixon ◽  
Nigel J. Clarke ◽  
Dale A. Schwab ◽  
...  
Keyword(s):  
High Throughput ◽  
Qualitative Agreement ◽  
Nucleocapsid Protein ◽  
Spike Protein ◽  
True Positive ◽  
Serum Samples ◽  
Igg Antibody ◽  
Positive Reactivity ◽  
Very High ◽  
Abbott Architect

ABSTRACT A total of 1,200 serum samples that were tested for SARS-CoV-2 IgG antibody using the Abbott Architect immunoassay targeting the nucleocapsid protein were run in 3 SARS-CoV-2 IgG immunoassays targeting spike proteins (DiaSorin Liaison, Ortho Vitros, and Euroimmun). Consensus-positive and consensus-negative interpretations were defined as qualitative agreement in at least 3 of the 4 assays. Agreement of the 4 individual assays with a consensus-negative interpretation (n = 610) ranged from 96.7% to 100%, and agreement with a consensus-positive interpretation (n = 584) ranged from 94.3% to 100%. Laboratory-developed inhibition assays were utilized to evaluate 49 consensus-negative samples that were positive in only one assay; true-positive reactivity was confirmed in only 2 of these 49 (4%) samples. These findings demonstrate very high levels of agreement among 4 SARS-CoV-2 IgG assays authorized for emergency use, regardless of antigen target or assay format. Although false-positive reactivity was identified, its occurrence was rare (no more than 1.7% of samples for a given assay).

scholarly journals Two doses of the SARS-CoV-2 BNT162b2 vaccine enhances antibody responses to variants in individuals with prior SARS-CoV-2 infection

2021 ◽  
pp. eabj0847
Author(s):  
Richard A Urbanowicz ◽  
Theocharis Tsoleridis ◽  
Hannah J Jackson ◽  
Lola Cusin ◽  
Joshua D Duncan ◽  
...  
Keyword(s):  
Immune Responses ◽  
Natural Infection ◽  
Neutralizing Antibody ◽  
Spike Protein ◽  
Serum Samples ◽  
Igg Antibody ◽  
Enzyme Immunoassays ◽  
Antigenic Exposure ◽  
The Impact ◽  
Prior Infection

Understanding the impact of prior infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on the response to vaccination is a priority for responding to the coronavirus disease 2019 (COVID-19) pandemic. In particular, it is necessary to understand how prior infection plus vaccination can modulate immune responses against variants of concern. To address this, we sampled 20 individuals with and 25 individuals without confirmed previous SARS-CoV-2 infection from a large cohort of healthcare workers followed serologically since April 2020. All 45 individuals had received two doses of the Pfizer-BioNTech BTN162b2 vaccine with a delayed booster at 10 weeks. Absolute and neutralizing antibody titers against wild-type SARS-CoV-2 and variants were measured using enzyme immunoassays and pseudotype neutralization assays. We observed antibody reactivity against lineage A, B.1.351 and P.1 variants with increasing antigenic exposure, either through vaccination or natural infection. This improvement was further confirmed in neutralization assays using fixed dilutions of serum samples. The impact of antigenic exposure was more evident in enzyme immunoassays measuring SARS-CoV-2 spike protein-specific IgG antibody concentrations. Our data show that multiple exposures to SARS-CoV-2 spike protein in the context of a delayed booster expand the neutralizing breadth of the antibody response to neutralization-resistant SARS-CoV-2 variants. This suggests that additional vaccine boosts may be beneficial in improving immune responses against future SARS-CoV-2 variants of concern.

A Prospective Study on TT Virus Infection in Transfusion-Dependent Patients With β-Thalassemia

Blood ◽  
1999 ◽  
Vol 93 (5) ◽  
pp. 1502-1505 ◽  
Author(s):  
Daniele Prati ◽  
Yu-Huei Lin ◽  
Claudia De Mattei ◽  
Jen-Kuei Liu ◽  
Elena Farma ◽  
...  
Keyword(s):  
Blood Donors ◽  
High Rate ◽  
Chain Reaction ◽  
Serum Samples ◽  
Tt Virus ◽  
Healthy Donors ◽  
Hcv Antibody ◽  
Polymerase Chain ◽  
A Prospective Study

A novel DNA virus designated TT virus (TTV) has been reported to be involved in the development of posttransfusion non–A-C hepatitis. We evaluated the frequency and natural course of TTV infection in a cohort of transfusion-dependent thalassemic patients in a 3-year follow-up study. Ninety-three serum hepatitis C virus (HCV) antibody-negative patients (median age of 8 years; range, 0 to 25) from eight centers were studied. Of them, 34 (37%) had an abnormal alanine-aminotransferase (ALT) baseline pattern, and the other 12 (13%) showed ALT flare-ups during the follow-up. TTV DNA in patient sera collected at the time of enrollment and at the end of follow-up was determined by polymerase chain reaction (PCR). In parallel, serum samples from 100 healthy blood donors were also tested. At baseline, 87 patient sera (93.5%) tested positive for the TTV DNA. Of these TTV DNA-positive patients, 84 (96.5%) remained viremic at the end of the study period. Of the 6 TTV DNA-negative patients, 3 acquired TTV infection during follow-up. However, no definite relation was observed between the results of TTV DNA determination and ALT patterns. TTV viremia was also detectable in 22% of blood donors. In conclusion, TTV infection is frequent and persistent among Italian transfusion-dependent patients. The high rate of viremia observed in healthy donors indicates that the parenteral route is not the only mode of TTV spread.

scholarly journals Prevalence of Antibodies to Onchocerca volvulus in Residents of Oaxaca, Mexico, Treated for 10 Years with Ivermectin

2005 ◽  
Vol 12 (1) ◽  
pp. 40-43 ◽  
Author(s):  
Alberto Gómez-Priego ◽  
Raymundo Mendoza ◽  
Jorge-Luis de-la-Rosa
Keyword(s):  
Crude Extract ◽  
Onchocerca Volvulus ◽  
Enzyme Linked Immunosorbent Assay ◽  
Ivermectin Treatment ◽  
Antibody Prevalence ◽  
Serum Samples ◽  
Igg Antibody ◽  
Prevalence Studies ◽  
Serological Studies

ABSTRACT Studies to determine the prevalence of antibodies to Onchocerca volvulus, prior to and after actions carried out to interrupt transmission, are scarce in Mexico. Here we report the prevalence of immunoglobulin G (IgG) and IgG4 antibodies in an enzyme-linked immunosorbent assay (ELISA) against a crude extract of O. volvulus adult worm in serum samples from persons under noninterrupted biannual treatment with ivermectin in areas of onchocercosis endemicity in Mexico. To perform the prevalence studies, the ELISA procedures were first evaluated. Serological studies were performed with serum samples from skin microfilaria carriers from Guatemala and from people microfilariodermic negative living in the same area as the Guatemalan patients. Sensitivity values for IgG or IgG4 detection were 71 and 86%, while specificities were 92 and 100%, respectively. No anti-O. volvulus antibodies were found in samples from nonendemic controls from Mexico, but 3 of 71 samples from residents in the onchocercosis area of Oaxaca, Mexico, and who have been under ivermectin treatment during the last 10 years were only positive to IgG. Notwithstanding that the IgG4 isotype was not detected and a low (4.2%) anti-O. volvulus IgG antibody prevalence was found, a seroepidemiological follow-up must be performed in order to confirm interruption of onchocercosis transmission in the area of Oaxaca, Mexico, in which onchocercosis is endemic.

scholarly journals The use of dried blood spots for the serological evaluation of SARS-CoV-2 antibodies

2021 ◽  
Author(s):  
Zheng Quan Toh ◽  
Rachel A Higgins ◽  
Jeremy Anderson ◽  
Nadia Mazarakis ◽  
Lien Anh Ha Do ◽  
...  
Keyword(s):  
Dried Blood Spots ◽  
Strongly Correlated ◽  
Serum Samples ◽  
Igg Antibody ◽  
Seropositivity Rate ◽  
Hard To Reach Populations ◽  
Specific Igg ◽  
Polymerase Chain ◽  
Paired Serum ◽  
Serum Igg Levels

Abstract Background To determine if dried blood spot specimens (DBS) can reliably detect severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies, we compared the SARS-CoV-2 IgG antibody response in paired serum and eluates from DBS specimens. Methods A total of 95 paired DBS and serum samples were collected from 74 participants (aged 1–63 years) as part of a household cohort study in Melbourne, Australia. SARS-CoV-2 IgG antibodies specific for the receptor-binding domain (RBD) and S1 proteins between serum and eluates from DBS specimens were compared using an FDA-approved ELISA method. Results Among the 74 participants, 42% (31/74) were children and the rest were adults. A total of 16 children and 13 adults were SARS-CoV-2 positive by polymerase chain reaction. The IgG seropositivity rate was similar between serum and DBS specimens (18.9% (18/95) versus 16.8% (16/95)), respectively. Similar RBD and S1-specific IgG levels were detected between serum and DBS specimens. Serum IgG levels strongly correlated with DBS IgG levels (r = 0.99, P < 0.0001) for both SARS-CoV-2 proteins. Furthermore, antibodies remained stable in DBS specimens for >3 months. Conclusions DBS specimens can be reliably used as an alternative to serum samples for SARS-CoV-2 antibody measurement. The use of DBS specimens would facilitate serosurveillance efforts particularly in hard-to-reach populations and inform public health responses including COVID-19 vaccination strategies.

scholarly journals Performance Evaluation of the Siemens SARS-CoV-2 Total Antibody and IgG Antibody Test

2021 ◽  
Author(s):  
Lisa Florin ◽  
Karel Maelegheer ◽  
Wouter Vandewal ◽  
Dirk Bernard ◽  
Johan Robbrecht
Keyword(s):  
Antibody Test ◽  
Control Group ◽  
Igg Antibody ◽  
Antibody Assays ◽  
Antibody Titers ◽  
Polymerase Chain ◽  
Kinetics Of ◽  
Antibody Tests ◽  
Positive Controls

Abstract Objective In this study, the performance of 2 commercially available SARS-CoV-2 antibody assays is evaluated. Methods The Siemens SARS-CoV-2 Total (COV2T) and IgG (COV2G) antibody tests were evaluated on a Siemens Atellica IM1300 analyzer. Imprecision was assessed with the CLSI EP15 protocol using positive controls. Ninety control group specimens were analyzed for specificity, and 175 specimens from 58 patients with polymerase chain reaction–confirmed SARS-CoV-2 were measured for the sensitivity and kinetics of the antibody response. Results Within-run and total imprecision were acceptable for both assays. Both tests showed a specificity of 100%. Sensitivity earlier in the disease state was greater for the COV2T assay than for the COV2G assay, but sensitivity >14 days after onset of symptoms approached 100% for both. For all patients, antibody titers remained above the seroconversion cutoff for all follow-up specimens. Conclusion This study shows acceptable performance for both the Siemens COV2T and COV2G test, although seroconversion occurs earlier with the COV2T test.

A Prospective Study on TT Virus Infection in Transfusion-Dependent Patients With β-Thalassemia

Blood ◽  
1999 ◽  
Vol 93 (5) ◽  
pp. 1502-1505 ◽  
Author(s):  
Daniele Prati ◽  
Yu-Huei Lin ◽  
Claudia De Mattei ◽  
Jen-Kuei Liu ◽  
Elena Farma ◽  
...  
Keyword(s):  
Blood Donors ◽  
High Rate ◽  
Chain Reaction ◽  
Serum Samples ◽  
Tt Virus ◽  
Healthy Donors ◽  
Hcv Antibody ◽  
Polymerase Chain ◽  
A Prospective Study

Abstract A novel DNA virus designated TT virus (TTV) has been reported to be involved in the development of posttransfusion non–A-C hepatitis. We evaluated the frequency and natural course of TTV infection in a cohort of transfusion-dependent thalassemic patients in a 3-year follow-up study. Ninety-three serum hepatitis C virus (HCV) antibody-negative patients (median age of 8 years; range, 0 to 25) from eight centers were studied. Of them, 34 (37%) had an abnormal alanine-aminotransferase (ALT) baseline pattern, and the other 12 (13%) showed ALT flare-ups during the follow-up. TTV DNA in patient sera collected at the time of enrollment and at the end of follow-up was determined by polymerase chain reaction (PCR). In parallel, serum samples from 100 healthy blood donors were also tested. At baseline, 87 patient sera (93.5%) tested positive for the TTV DNA. Of these TTV DNA-positive patients, 84 (96.5%) remained viremic at the end of the study period. Of the 6 TTV DNA-negative patients, 3 acquired TTV infection during follow-up. However, no definite relation was observed between the results of TTV DNA determination and ALT patterns. TTV viremia was also detectable in 22% of blood donors. In conclusion, TTV infection is frequent and persistent among Italian transfusion-dependent patients. The high rate of viremia observed in healthy donors indicates that the parenteral route is not the only mode of TTV spread.

scholarly journals Long-lasting humoral immunity in Covid-19 infected patients at a University Hospital Clinic in Östergötland County Council during 2020-2021

2021 ◽  
Author(s):  
M Azharuddin ◽  
D Aili ◽  
R Selegård ◽  
Sajjad Naeimipour ◽  
M Sunnerhagen ◽  
...  
Keyword(s):  
County Council ◽  
University Hospital ◽  
Spike Protein ◽  
Test Results ◽  
Structural Protein ◽  
Serum Samples ◽  
Serum Igg ◽  
Nasal Swabs ◽  
Study Participants

AbstractLongitudinal serum samples and nasopharyngeal/nasal swab samples were collected from forty-eight individuals (median age 66yrs) with Covid-19 PCR-positive test results at Linköping University Hospital. Samples were collected from initial visit and for 6 months follow up. Presence of serum IgG and IgA against SARS-CoV-2 antigens (S1-spike, nucleocapsid and NSP3) were analyzed. Nasal swabs were tested for presence of IgA against the outer envelope S1 spike protein. Ninety-two percent of participants were seropositive against SARS-CoV-2 recombinant proteins at day 28 from study entry and all (100%) were seropositive from samples collected at 2 months or later. The most common antibody responses (both serum IgG, mainly IgG1 and IgA) were detected against the S1-spike protein and the nucleoprotein. In samples collected from nasal tissues considerably lower frequencies of IgA-positive reactivities were detected. Sixteen to 18 percent of study participants showed detectable IgA levels in nasal samples, except at day 60 when 36% of tested individuals showed presence of IgA against the S1-spike protein. The study suggests that the absolute majority of studied naturally infected Covid-19 patient in the Linkoping, Ostergotland health region develop over 6 months lasting detectable levels of serum IgG and IgA responses towards the SARS-CoV-2 S1-spike protein as well as against the nucleoprotein, but not against the non-structural protein 3.

scholarly journals Comparative Clinical Evaluation of the Roche Elecsys and Abbott Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Serology Assays for Coronavirus Disease 2019 (COVID-19)

2020 ◽  
Vol 145 (1) ◽  
pp. 32-38 ◽  
Author(s):  
Shaun S. Tan ◽  
Sharon Saw ◽  
Ka Lip Chew ◽  
Cindy Wang ◽  
Anastacia Pajarillaga ◽  
...  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Clinical Symptoms ◽  
Test Results ◽  
Serum Samples ◽  
False Negatives ◽  
Antiretroviral Medication ◽  
Polymerase Chain ◽  
Negative Controls ◽  
Level Of Agreement ◽  
Abbott Architect

Context.— The use of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) serologic tests detects antibodies in the host, contributing to the identification of individuals who have been exposed to coronavirus disease 2019 (COVID-19). Objective.— To critically evaluate 2 commercially available SARS-CoV-2 serology tests. Design.— A total of 333 unique, nonduplicated serum samples obtained from COVID-19 patients (n = 170) and negative controls (n = 163) obtained before December 2019 were used in the study. Samples were tested on the Roche E411 and Abbott Architect i4000SR platforms, and results were correlated to reverse transcription polymerase chain reaction (PCR) results and clinical symptoms. Results.— There was a strong level of agreement in the qualitative results between both assays, with a Cohen κ value of .840, P < .001. The specificity for both Roche and Abbott were excellent at 100%. Roche exhibited marginally better performance in the 21 days or more group with a sensitivity of 90.6% (95% CI, 75.8%–96.8%) versus an Abbott sensitivity of 84.4% (95% CI, 68.3%–93.1%), as well as in the 14- to 20-day group with a sensitivity of 85.7% (95% CI, 65.4%–95.0%) versus an Abbott sensitivity of 81.0% (95% CI, 60.0%–92.3%). Less than 14 days of symptoms groups exhibited poor sensitivity at less than 50% for both assays. The areas under curve (± standard error) for Roche (0.894 ± 0.025, P < .001) and Abbott (0.884 ± 0.026, P < .001) were very similar. Potential confounders for negative serologic results include antiretroviral medication use and pauci-symptomatic patients. Conclusions.— Specificities for high-throughput Roche and Abbott immunoassays are excellent, but users need to be cautious to interpret serologic test results after 14 days of symptoms to avoid false negatives.

scholarly journals A Decrease in the Immunoglobulin G Antibody Response against the VlsE Protein of Borrelia burgdorferi Sensu Lato Correlates with the Resolution of Clinical Signs in Antibiotic-Treated Patients with Early Lyme Disease

2006 ◽  
Vol 13 (4) ◽  
pp. 525-529 ◽  
Author(s):  
Antonella Marangoni ◽  
Vittorio Sambri ◽  
Silvia Accardo ◽  
Francesca Cavrini ◽  
Valeria Mondardini ◽  
...  
Keyword(s):  
Lyme Disease ◽  
Antibody Titer ◽  
Immunoglobulin G ◽  
Erythema Migrans ◽  
Clinical Signs ◽  
Response To Treatment ◽  
Borrelia Burgdorferi Sensu Lato ◽  
Serum Samples ◽  
Igg Antibody

ABSTRACT The purpose of this study was to evaluate the diagnostic performance of the LIAISON Borrelia Screen (Diasorin, Saluggia, Italy), a new automated immunoassay based on the chemiluminescent technology (chemiluminescence immunoassay). To assess whether a decrease in a negative value in the anti-VlsE immunoglobulin G (IgG) antibody titer was correlated with a positive response to treatment, a group of serially collected serum samples from 67 patients with culture-confirmed erythema migrans was retrospectively studied. All the patients had been treated with antibiotics and were free of disease within 3 to 6 months of follow-up. All the 15 patients who were found to be IgG positive at the time of enrollment and who were bled at least four times during the follow-up became IgG seronegative at 2 to 6 months posttreatment. These results indicate that a decline in the anti-VlsE antibody titer coincides with effective antimicrobial therapy in patients with early localized Lyme disease.

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