scholarly journals Seroprevalence of Anti-SARS-CoV-2 IgG and IgM among Adults over 65 Years Old in the South of Italy

Diagnostics ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 483
Author(s):  
Immacolata Polvere ◽  
Alfredina Parrella ◽  
Giovanna Casamassa ◽  
Silvia D’Andrea ◽  
Annamaria Tizzano ◽  
...  
Keyword(s):  
Antibody Response ◽  
Immunoglobulin M ◽  
Molecular Testing ◽  
Elisa Assay ◽  
The South ◽  
Serum Samples ◽  
Serological Screening ◽  
Rna Detection ◽  
In Vitro Diagnostic

SARS-CoV-2 is a zoonotic betacoronavirus associated with worldwide transmission of COVID-19 disease. By the beginning of March, WHO reported about 113,820,000 confirmed cases including more than 2,527,000 deaths all over the world. However, the true extent of virus circulation or its real infection/fatality ratio is not well-estimated due to the huge portion of asymptomatic infections. In this observational study, we have estimated the prevalence of specific immunoglobulin M and G directed towards SARS-CoV-2 antigen in a cohort of 1383 adult volunteers aged over 65 years old, living in the district of Benevento, in the South of Italy. Serological screening was carried out on capillary blood in September 2020, seven months after pandemic outbreak in Italy, to evaluate virus circulation and antibody response among elderly adults, in which severe symptoms due to viral infection are more common. The overall seroprevalence of anti-SARS-CoV-2 antibodies was 4.70% (CI 3.70%–5.95%) with no statistically significant differences between sexes. Among these, 69.69% (CI 55.61%–77.80%) tested positive to IgM, 23.08% (CI 14.51%–34.64%) to IgG and 9.23% (CI 4.30%–18.71%) was positive for both. All patients that were positive to IgM underwent molecular testing through RT-qPCR on oral-rhino pharyngeal swabs and only one specimen was positive for SARS-CoV-2 RNA detection. Instead, the presence of IgG from screened volunteers was confirmed by re-testing serum samples using both an ELISA assay validated for in vitro diagnostic use (IVD) and a recently published synthetic peptide-based ELISA assay. In conclusion, our report suggests that (1) early restrictions were successful in limiting COVID-19 diffusion in the district of Benevento; (2) rapid serological analysis is an ideal testing for both determining real seroprevalence and massive screening, whereas detection of viral RNA remains a gold standard for identification of infected patients; (3) even among people without COVID-19 related symptoms, the antibody response against SARS-CoV-2 antigens has individual features.

scholarly journals Immunochromatographic assays for COVID-19 epidemiological screening: our experience

2020 ◽  
Author(s):  
Andrea Bartolini ◽  
Margherita Scapaticci ◽  
Marina Bioli ◽  
Tiziana Lazzarotto ◽  
Maria Carla Re ◽  
...  
Keyword(s):  
Healthcare Workers ◽  
World Health ◽  
Rt Pcr ◽  
Serological Screening ◽  
Rapid Assays ◽  
In Vitro Diagnostic ◽  
Biomedical Prevention ◽  
Health Organization ◽  
Performance Validation

In March 2020, the World Health Organization (WHO) declared a pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Due to the absence of effective treatment or biomedical prevention, understanding potential post infection immunity has important implications for epidemiologic assessments. For this reason, increasing number of in vitro diagnostic companies are developing serological assays to detect antibodies against SARS-CoV-2, but most of them lack the validation by third parties in relation to their quality, limiting their usefulness. We submitted to serological screening by two different immunochromatographic (IC) rapid testing for detection of IgG and IgM against SARS-CoV-2, 151 asymptomatic or minimally symptomatic healthcare workers previously tested positive for SARS-CoV-2 RT-PCR in order to evaluate the performance of rapid assays. Results showed discrepancies between molecular and IC results, and an inconsistency of immunoglobulins positivity patterns when compared to ELISA/CLIA results, highlighting the absolute necessity of assays performance validation before their marketing and use, in order to avoid errors in the results evaluation at both clinical and epidemiological level.

scholarly journals In Vitro and In Vivo Neutralization of the Relapsing Fever Agent Borrelia hermsii with Serotype-Specific Immunoglobulin M Antibodies

2001 ◽  
Vol 69 (2) ◽  
pp. 1009-1015 ◽  
Author(s):  
Alan G. Barbour ◽  
Virgilio Bundoc
Keyword(s):  
Monoclonal Antibodies ◽  
Antibody Response ◽  
Immunoglobulin M ◽  
Enzyme Linked Immunosorbent Assay ◽  
Relapsing Fever ◽  
Borrelia Hermsii ◽  
Intact Cells ◽  
Whole Cells

ABSTRACT The antigenic variation of the relapsing fever agent Borrelia hermsii is associated with changes in the expression of the Vlp and Vsp outer membrane lipoproteins. To investigate whether these serotype-defining proteins are the target of a neutralizing and protective antibody response, monoclonal antibodies were produced from spleens of infected mice just after clearance of serotype 7 cells from the blood. Two immunoglobulin M monoclonal antibodies, H7-7 and H7-12, were studied in detail. Both antibodies specifically agglutinated serotype 7 cells and inhibited their growth in vitro. Administered to mice before or after infection, both antibodies provided protection against infection or substantially reduced the number of spirochetes in the blood of mice after infection. Whereas antibody H7-12 bound to Vlp7 in Western blotting, enzyme-linked immunosorbent assay, and immunoprecipitation assays, as well as to whole cells in other immunoassays, antibody H7-7 only bound to wet, intact cells of serotype 7. Antibody H7-7 selected against cells expressing Vlp7 in vitro and in vivo, an indication that Vlp7 was a conformation-sensitive antigen for the antibody. Vaccination of mice with recombinant Vlp7 with adjuvant elicited antibodies that bound to fixed whole cells of serotype 7 and to Vlp7 in Western blots, but these antibodies did not inhibit the growth of serotype 7 in vitro and did not provide protection against an infectious challenge with serotype 7. The study established that a Vlp protein was the target of a neutralizing antibody response, and it also indicated that the conformation and/or the native topology of Vlp were important for eliciting that immunity.

scholarly journals Children with Invasive Staphylococcus aureus Disease Exhibit a Potently Neutralizing Antibody Response to the Cytotoxin LukAB

2013 ◽  
Vol 82 (3) ◽  
pp. 1234-1242 ◽  
Author(s):  
Isaac P. Thomsen ◽  
Ashley L. DuMont ◽  
David B. A James ◽  
Pauline Yoong ◽  
Benjamin R. Saville ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Antibody Response ◽  
High Titer ◽  
Humoral Response ◽  
Neutralizing Antibody ◽  
Human Neutrophils ◽  
Serum Samples ◽  
Marked Rise ◽  
Content Type

ABSTRACTDespite the importance ofStaphylococcus aureusas a common invasive bacterial pathogen, the humoral response to infection remains inadequately defined, particularly in children. The purpose of this study was to assess the humoral response to extracellular staphylococcal virulence factors, including the bicomponent leukotoxins, which are critical for the cytotoxicity ofS. aureustoward human neutrophils. Children with culture-provenS. aureusinfection were prospectively enrolled and stratified by disease type. Fifty-three children were enrolled in the study, of which 90% had invasive disease. Serum samples were obtained during the acute (within 48 h) and convalescent (4 to 6 weeks postinfection) phases, at which point both IgG titers againstS. aureusexotoxins were determined, and the functionality of the generated antibodies was evaluated. Molecular characterization of clinical isolates was also performed. We observed a marked rise in antibody titer from acute-phase to convalescent-phase sera for LukAB, the most recently describedS. aureusbicomponent leukotoxin. LukAB production by the isolates was strongly correlated with cytotoxicityin vitro, and sera containing anti-LukAB antibodies potently neutralized cytotoxicity. Antibodies toS. aureusantigens were detectable in healthy pediatric controls but at much lower titers than in sera from infected subjects. The discovery of a high-titer, neutralizing antibody response to LukAB during invasive infections suggests that this toxin is producedin vivoand that it elicits a functional humoral response.

scholarly journals Gaps in the Traceability Chain of Human Growth Hormone Measurements

2013 ◽  
Vol 59 (7) ◽  
pp. 1074-1082 ◽  
Author(s):  
Sébastien Boulo ◽  
Katja Hanisch ◽  
Martin Bidlingmaier ◽  
Cristian-Gabriel Arsene ◽  
Mauro Panteghini ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Human Growth Hormone ◽  
Human Growth ◽  
Higher Order ◽  
Serum Samples ◽  
Traceability Chain ◽  
Eu Directive ◽  
In Vitro Diagnostic ◽  
Relative Differences

BACKGROUND Human growth hormone (hGH) is measured for the diagnosis of secretion disorders. These measurements fall under the EU Directive 98/79/EC on in vitro diagnostic medical devices requiring traceability of commercial calibrator values to higher-order reference materials or procedures (Off J Eur Communities 1998 Dec 7;L 331:1–37). External quality assessment schemes show large discrepancies between results from different methods, even though most methods provide results traceable to the recommended International Standard (IS 98/574). The aim of this study was to investigate possible causes for these discrepancies. METHODS We investigated the commutability and recovery of hGH in reconstituted IS 98/574. We tested different reconstitution protocols and used 4 different serum matrices for spiking. These IS preparations were measured together with serum samples. We quantified hGH by 5 different methods in 4 different laboratories. RESULTS Results from the different methods correlated well for the serum samples. Mean discrepancies between results from different methods were ≤20%. None of the IS preparations was commutable for all the method comparisons. The recovery of hGH in preparations of IS 98/574 depended on the reconstitution protocol (>10-fold differences) and BACKGROUND matrix (relative differences ≤17% for different serum matrices). CONCLUSIONS The use of different protocols for reconstitution and spiking of hGH reference preparations affects quantification by immunoassays, potentially leading to a bias between commercial methods, despite the use of calibrators with values claimed to be traceable to the same higher-order reference material.

scholarly journals Complement Activation Is Required for Induction of a Protective Antibody Response against West Nile Virus Infection

2005 ◽  
Vol 79 (12) ◽  
pp. 7466-7477 ◽  
Author(s):  
Erin Mehlhop ◽  
Kevin Whitby ◽  
Theodore Oliphant ◽  
Anantha Marri ◽  
Michael Engle ◽  
...  
Keyword(s):  
West Nile Virus ◽  
Antibody Response ◽  
Severe Infection ◽  
West Nile Virus Infection ◽  
The Elderly ◽  
Immunoglobulin M ◽  
Dependent Manner ◽  
West Nile ◽  
Protective Antibody

ABSTRACT Infection with West Nile virus (WNV) causes a severe infection of the central nervous system (CNS) with higher levels of morbidity and mortality in the elderly and the immunocompromised. Experiments with mice have begun to define how the innate and adaptive immune responses function to limit infection. Here, we demonstrate that the complement system, a major component of innate immunity, controls WNV infection in vitro primarily in an antibody-dependent manner by neutralizing virus particles in solution and lysing WNV-infected cells. More decisively, mice that genetically lack the third component of complement or complement receptor 1 (CR1) and CR2 developed increased CNS virus burdens and were vulnerable to lethal infection at a low dose of WNV. Both C3-deficient and CR1- and CR2-deficient mice also had significant deficits in their humoral responses after infection with markedly reduced levels of specific anti-WNV immunoglobulin M (IgM) and IgG. Overall, these results suggest that complement controls WNV infection, in part through its ability to induce a protective antibody response.

scholarly journals Clinical Evaluation of an Immunochromatographic-Based IgM/IgG Antibody Assay (GenBody™ COVI040) for Detection of Antibody Seroconversion in Patients with SARS-CoV-2 Infection

Diagnostics ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 537
Author(s):  
Doyeong Kim ◽  
Jihoo Lee ◽  
Jyotiranjan Bal ◽  
Chom-Kyu Chong ◽  
Jong Ho Lee ◽  
...  
Keyword(s):  
High Sensitivity ◽  
Negative Control ◽  
Immunoglobulin M ◽  
Antibody Assay ◽  
Igg Antibody ◽  
South Korean ◽  
Korean Ministry ◽  
In Vitro Diagnostic ◽  
Polymerase Chain

There is a need for accurate diagnostic tests for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the cause of coronavirus disease (COVID-19). This study aimed to evaluate the diagnostic accuracy of an immunochromatography-based immunoglobulin G (IgG)/immunoglobulin M (IgM) antibody assay (GenBody™ COVI040) for detecting SARS-CoV-2 antibody seroconversion in COVID-19 patients. A total of 130 samples, serially collected from patients with confirmed COVID-19, and 100 negative control samples were tested for anti-SARS-CoV-2 IgM and IgG using the GenBody™ COVI040 assay following the South Korean Ministry of Food and Drug Safety guidelines on the review and approval of in vitro diagnostic devices for COVID-19. Reverse-transcription polymerase chain reaction results were used as the comparator. The overall sensitivity of the GenBody™ COVI040 assay was 97.69% (95% confidence interval (CI): 93.40–99.52%). The sensitivity of the assay increased with time post symptom onset (PSO) (sensitivity ≤6 days PSO: 78.57%, 95% CI: 49.20–95.34%; sensitivity 7–13 days PSO: 100%, 95% CI: 87.23–100%; and sensitivity ≥14 days PSO: 100%, 95% CI: 95.94–100%). The specificity of the assay was 100% (95% CI: 96.38–100%). The GenBody™ COVI040 assay showed high sensitivity and specificity, making it a promising diagnostic test to monitor COVID-19.

scholarly journals Immunoglobulin M antibody response against Mycoplasma pneumoniae lipid antigen in patients with acute pancreatitis

1978 ◽  
Vol 8 (2) ◽  
pp. 113-118
Author(s):  
P O Leinikki ◽  
P Panzar ◽  
H Tykkä
Keyword(s):  
Acute Pancreatitis ◽  
Antibody Response ◽  
Mycoplasma Pneumoniae ◽  
Lipid Extraction ◽  
Pancreatic Tissue ◽  
Immunoglobulin M ◽  
Serum Samples ◽  
Igm Antibody ◽  
Lipid Antigen ◽  
Serial Serum

Serial serum samples from patients with acute pancreatitis showed a significant increase in antibodies against methanol-chloroform-extracted lipid antigen from Mycoplasma pneumoniae when tested by complement fixation. The antibodies did not react with antigens prepared from other human mycoplasmas or from pancreatic tissue by lipid extraction. The antibodies were predominantly immunoglobulin M (IgM). No correlation with cold agglutinins or cardiolipid complement-fixing antibodies was found. The IgM antibody response seemed to be prolonged: after 3 to 4 weeks the antibodies were still in many cases exclusively IgM. Similar IgM responses were also found in certain cases of acute meningoencephalitis. We postulate that during the disease antigenic components identical or very similar to major determinants in the M. pneumoniae lipid antigen are revealed and elicit the IgM antibody response. Their resemblance to natural antibodies and their possible biological role is discussed.

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