scholarly journals Enzyme-linked immunosorbent assays for the measurement of specific antibodies in experimentally induced ovine toxoplasmosis

1988 ◽  
Vol 100 (2) ◽  
pp. 205-212 ◽  
Author(s):  
R. A. Payne ◽  
D. H. M. Joynson ◽  
A. J. Wilsmore
Keyword(s):  
Toxoplasma Gondii ◽  
Serum Samples ◽  
Specific Antibodies ◽  
Capture Assay ◽  
Previous Infection ◽  
Specific Igg ◽  
Immunosorbent Assays ◽  
Antibody Class ◽  
Antibody Levels ◽  
Indirect Assay

SUMMARYTachyzoitcs of the RH strain of Toxoplasma gondii were inoculated intravenously into sheep following which serum samples were collected at approximately weekly intervals for 9 months. The sera were examined by the toxoplasma dye test and two enzymc-linkcd immunosorbent assays (ELISA) specifically developed for investigations of ovine toxoplasmosis. One was an antibody class capture assay for the detection of anti-toxoplasma specific IgM, the other an indirect assay which detected anti-toxoplasma IgG.Some of the sheep had antibodies to toxoplasma prior to inoculation but none had specific IgM. Sera collected 17 days after inoculation showed that all had raised specific antibody levels but the only sheep that produced specific antitoxoplasma IgM were those that were initially without any antibody. Specific IgM could be detected in all these particular sheep for at least 1 month after infection and up to 3 months in some. Specific IgG persisted at high levels for at least 3 months and could still be detected at moderate levels for at least 9 months. The ELISA methods described are simple to perform and could clearly distinguish between previous infection and this experimental infection with Toxoplasma gondii.

Significance of Specific Immunoglobulins Determined by the Chemiluminescence Reaction in Intrauterine Maternal-fetal Infections of TORCH Syndrome

2019 ◽  
Vol 70 (1) ◽  
pp. 96-101
Author(s):  
Delia Mira Berceanu Vaduva ◽  
Dana Emilia Velimirovici ◽  
Livia Stanga ◽  
Marcel Mihai Berceanu Vaduva ◽  
Smaranda Arghirescu ◽  
...  
Keyword(s):  
Toxoplasma Gondii ◽  
Positive Result ◽  
Rubella Virus ◽  
Antibody Test ◽  
Fetal Mortality ◽  
Infectious Agents ◽  
Serum Samples ◽  
Mortality And Morbidity ◽  
Specific Antibodies ◽  
Specific Igg

Because the TORCH Syndrome groups infectious agents which cross the placenta during pregnancy and due to that cause the majority of malformative fetopaties, our porpose was to determin specific IgG and IgM antibodies for Cytomegalovirus, Rubella virus and Toxoplasma gondii. We studied 95 serum samples from 93 pregnant females and 2 cilds, being analyzed by a private laboratory in Timisoara between july 2015 � june 2016. Specific antibodies IgG and IgM were found for Rubella virus in 75 of the samples, for Cytomegalovirus in 82 and for toxoplasmosis 92. In this process of determination we used Access 2 (Beckman Coulter) and Immulite 1000 (Siemens) analysers, which use the chemiluminescence reaction. For 72 cases (77.42%) specific antibodies for all tests of the TORCH complex were performed. From all the patients 11 chosed to determine antibodies just for one of the infections of the TORCH Syndrome and 10 patients asked for determining of specific antibodies for two infections of the TORCH Syndrome. 53 (64.63%) of the 82 patients tested for anti-CMV IgG specific antibodies had positive result, which signifies former presence of CMV. 64 (85.33%) of the 75 patients tested for anti-rubella specific antibodies had an IgG positive result. Interpreting of results took in counter the vaccinal status. 6 patients (8%) did not contact the Rubella virus and did were not vaccinated. The level of specific IgG anti-Toxoplasma gondii antibodies was positive for 2 (2.17%) patients of 92. IgM specific antibody test was negative. In pregnant women TORCH Syndrome diagnosis is a must, especially if the medical abortion is the correct decision. Identifyeing infectious agents implicated in TORCH Syndrome can lead to an important decrease of maternal and fetal mortality and morbidity.

scholarly journals Sensitive detection of SARS-CoV-2-specific-antibodies in dried blood spot samples

2020 ◽  
Author(s):  
Gabriella L. Morley ◽  
Stephen Taylor ◽  
Sian Jossi ◽  
Marisol Perez-Toledo ◽  
Sian E. Faustini ◽  
...  
Keyword(s):  
Sampling Method ◽  
Dried Blood Spot ◽  
Serological Testing ◽  
Spike Glycoprotein ◽  
Serum Samples ◽  
Perfect Agreement ◽  
Specific Antibodies ◽  
Antibody Levels ◽  
Matched Samples ◽  
Blood Spot

AbstractImportancePopulation-wide serological testing is an essential component in understanding the COVID-19 pandemic. The logistical challenges of undertaking widespread serological testing could be eased through use of a reliable dried blood spot (DBS) sampling method.ObjectiveTo validate the use of dried blood spot sampling for the detection of SARS-CoV-2-specific antibodies.Design, setting and participantsEighty-seven matched DBS and serum samples were obtained from eighty individuals, including thirty-one who were previously PCR-positive for SARS-CoV-2. DBS eluates and sera were used in an ELISA to detect antibodies to the viral spike protein.ResultsSpecific anti-SARS-Cov-2 spike glycoprotein antibodies were detectable in both serum and DBS eluate and there was a significant correlation between the antibody levels detected in matched samples (r = 0.96, p<0.0001). Using serum as the gold standard in the assay, matched DBS samples achieved a Cohen’s kappa coefficient of 0.975 (near-perfect agreement), a sensitivity of 98.1% and specificity of 100%, for detecting anti-spike glycoprotein antibodies.Conclusions and relevanceEluates from DBS samples are a reliable and reproducible source of antibodies to be used for the detection of SARS-CoV-2-specific antibodies. The use of DBS sampling could complement the use of venepuncture in the immunosurveillance of COVID-19 in both low and high income settings.

Neutralizing antibody titers six months after Comirnaty vaccination: kinetics and comparison with SARS-CoV-2 immunoassays

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Andrea Padoan ◽  
Chiara Cosma ◽  
Francesco Bonfante ◽  
Foscarina della Rocca ◽  
Francesco Barbaro ◽  
...  
Keyword(s):  
Vaccine Dose ◽  
Neutralizing Antibody ◽  
University Hospital ◽  
Serum Samples ◽  
Viral Neutralization ◽  
Previous Infection ◽  
Antibody Titers ◽  
Males And Females ◽  
Antibody Levels

Abstract Objectives mRNA vaccines, including Comirnaty (BNT162b2 mRNA, BioNTech-Pfizer), elicit high IgG and neutralizing antibody (NAb) responses after the second dose, but the progressive decrease in serum antibodies against SARS-CoV-2 following vaccination have raised questions concerning long-term immunity, decreased antibody levels being associated with breakthrough infections after vaccination, prompting the consideration of booster doses. Methods A total number of 189 Padua University-Hospital healthcare workers (HCW) who had received a second vaccine dose were asked to collect serum samples for determining Ab at 12 (t12) and 28 (t28) days, and 6 months (t6m) after their first Comirnaty/BNT162b2 inoculation. Ab titers were measured with plaque reduction neutralization test (PRNT), and three chemiluminescent immunoassays, targeting the receptor binding domain (RBD), the trimeric Spike protein (trimeric-S), and surrogate viral neutralization tests (sVNT). Results The median percentages (interquartile range) for decrease in antibodies values 6 months after the first dose were 86.8% (67.1–92.8%) for S-RBD IgG, 82% (58.6–89.3%) for trimeric-S, 70.4% (34.5–86.4%) for VNT-Nab, 75% (50–87.5%) for PRNT50 and 75% (50–93.7%) for PRNT90. At 6 months, neither PRNT titers nor VNT-Nab and S-RBD IgG bAb levels correlated with age (p=0.078) or gender (p=0.938), while they were correlated with previous infection (p<0.001). Conclusions After 6 months, a method-independent reduction of around 90% in anti-SARS-CoV-2 antibodies was detected, while no significant differences were found between values of males and females aged between 24 and 65 years without compromised health status. Further efforts to improve analytical harmonization and standardization are needed.

scholarly journals Antenatal Screening for Hepatitis B and Antibodies to Toxoplasma gondii and Rubella Virus: Evaluation of Two Commercial Immunoassay Systems

2001 ◽  
Vol 8 (4) ◽  
pp. 785-787 ◽  
Author(s):  
Robert J. A. Diepersloot ◽  
Hiske Dunnewold-Hoekstra ◽  
Jorien Kruit-den Hollander ◽  
Fer Vlaspolder
Keyword(s):  
Toxoplasma Gondii ◽  
Hepatitis B ◽  
Rubella Virus ◽  
Hepatitis B Surface Antigen ◽  
Random Access ◽  
Antenatal Screening ◽  
Serum Samples ◽  
Discrepancy Analysis ◽  
Microparticle Enzyme Immunoassay ◽  
Antibody Levels

ABSTRACT A comparative evaluation of the Abbott AxSYM and DPC Immulite random-access analyzers was performed using 497 prospectively collected serum samples. These samples were sent to the laboratory for routine antenatal screening for hepatitis B surface antigen and immunoglobulin G (IgG) and IgM antibodies to Toxoplasma gondii and rubella virus. The overall agreement between the two assay systems ranged from 97.4 to 100%. After discrepancy analysis, the outcome in terms of sensitivity and specificity varied from 98.2 to 100% for all but one of the assays tested. The AxSYM rubella virus IgG assay tended to report protective or indeterminate antibody levels in 1% of the samples. This shortcoming might be overcome by raising the cutoff of the microparticle enzyme immunoassay system.

scholarly journals Seroprevalence of Antibodies against Serogroup C Meningococci in England in the Postvaccination Era

2008 ◽  
Vol 15 (11) ◽  
pp. 1694-1698 ◽  
Author(s):  
Caroline L. Trotter ◽  
Ray Borrow ◽  
Jamie Findlow ◽  
Ann Holland ◽  
Sarah Frankland ◽  
...  
Keyword(s):  
Similar Pattern ◽  
Geometric Mean ◽  
Herd Immunity ◽  
Age Groups ◽  
Serum Samples ◽  
The United Kingdom ◽  
Specific Igg ◽  
Catch Up ◽  
Antibody Levels ◽  
Mean Concentration

ABSTRACT The United Kingdom introduced meningococcal serogroup C conjugate (MCC) vaccines in 1999, resulting in substantial declines in serogroup C disease and carriage. Here, we measured the age-specific prevalence of serum bactericidal antibodies (SBA) to Neisseria meningitidis serogroup C and immunoglobulin G (IgG) concentrations to serogroups A, C, W-135, and Y in 2,673 serum samples collected in England between 2000 and 2004. We compared the seroprevalence of SBA titers of ≥8 in the postvaccination era with results from an earlier prevaccination study conducted using the same methods. We found that the percentages of individuals with protective SBA titers were higher in 2000 to 2004 in all of the age groups targeted for MCC vaccination. In the postvaccine era, the prevalence of protective titers was high (75%) in children who had recently been offered routine immunization, but this fell to 36% more than 18 months after scheduled immunization. In the cohorts targeted in the catch-up campaign, the percentage achieving SBA titers of ≥8 was higher in children offered the vaccine at ages 5 to 17 years than in children offered the vaccine at ages 1 to 4 years. The geometric mean concentration (GMC) IgG for serogroup C followed a similar pattern, corresponding to the age at and time since scheduled MCC vaccination. Serogroup-specific IgG GMCs for W-135 and Y were low and showed little variation by age. Serogroup A IgG GMCs were higher, possibly reflecting exposure to cross-reacting antigens. Although the incidence of serogroup C disease remains low due to persisting herd effects, population antibody levels to serogroup C meningococci should be monitored so that potentially susceptible age groups can be identified should herd immunity wane.

Evaluation of frequency of antibodies against Toxoplasma gondii,Neospora caninum and Sarcocystis spp. and transmission routes in sheep from Humid Pampa, Argentina

2018 ◽  
Vol 63 (2) ◽  
pp. 416-421 ◽  
Author(s):  
Yanina P. Hecker ◽  
Fernando Mogaburu Masson ◽  
Joaquín I. Armendano ◽  
Juan Cora ◽  
Carlos Flores Olivares ◽  
...  
Keyword(s):  
Toxoplasma Gondii ◽  
Neospora Caninum ◽  
Transmission Route ◽  
Serum Samples ◽  
Specific Antibodies ◽  
Adult Sheep ◽  
Sarcocystis Spp ◽  
Serological Status ◽  
The Impact

AbstractThe aim of this study was to describe the frequency of ovine specific antibodies toToxoplasma gondii,Neospora caninumandSarcocystisspp. and to estimate different transmission routes of these infections. One hundred and thirty Texel sheep and their 117 Texel lambs were included in the study. Serum samples were tested for antibodies toT.gondii,N.caninumandSarcocystisspp. using IFAT.Toxoplasma gondiiseroprevalence was 10.00% in sheep (IC95%: 4.80–15.20%), being higher in adult sheep (≥12 year) than in younger sheep (OR 1.30; 95% CI, 1.10–1.50).N.caninumandSarcocystisspp. seroprevalences were 1.54% (IC95%: 0.00–5.70) and 72.09% (IC95%: 67.70–82.70), respectively, with no association between age and seropositivity in sheep (P>0.05).T.gondiiseroprevalence in lambs was 4.27% (IC95%: 0.61–7.94). No association betweenT.gondiiserological status in sheep and their lambs was detected (P= 0.07). TwoT.gondiiandSarcocystisspp. seropositive lambs were euthanized andT.gondiiandSarcocystisspp. DNA was detected by PCR in their tissues. In conclusion, the increase ofT.gondiiseropositivity in relationship with sheep age and the lack of association between sheep-lamb serological status, suggest that horizontal infection is the main transmission route in this flock as reported before. Due to the low number ofN.caninum-seropositive ewes no assumptions can be done about the impact of this parasite in this flock. According with previous reports, the main transmission route forSarcocystisspp. in this species in the present study was horizontal.

scholarly journals Evaluation of Enzyme-Linked Immunosorbent Assays for Detection of Mycoplasma bovis-Specific Antibody in Bison Sera

2013 ◽  
Vol 20 (9) ◽  
pp. 1405-1409 ◽  
Author(s):  
Karen B. Register ◽  
Randy E. Sacco ◽  
Steven C. Olsen
Keyword(s):  
Infectious Disease ◽  
Protein G ◽  
Mycoplasma Bovis ◽  
Content Type ◽  
Specific Serum ◽  
History Of ◽  
Specific Igg ◽  
Immunosorbent Assays ◽  
Comparison Of The Results ◽  
Antibody Levels

ABSTRACTMycoplasma bovishas recently emerged as a significant and costly infectious disease problem in bison. A method for the detection ofM. bovis-specific serum antibodies is needed in order to establish prevalence and transmission patterns. Enzyme-linked immunosorbent assays (ELISAs) validated for the detection ofM. bovis-specific serum IgG in cattle are commercially available, but their suitability for bison sera has not been determined. A collection of bison sera, most from animals with a known history of infection or vaccination withM. bovis, was tested forM. bovis-specific IgG using commercially available kits as well as an in-house ELISA in which either cattle or bisonM. bovisisolates were used as a source of antigen. Comparison of the results demonstrates that ELISAs optimized for cattle sera may not be optimal for the identification of bison seropositive forM. bovis, particularly those with low to moderate antibody levels. The reagent used for the detection of bison IgG and the source of the antigen affect the sensitivity of the assay. Optimal performance was obtained when the capture antigen was derived from bison isolates rather than cattle isolates and when a protein G conjugate rather than an anti-bovine IgG conjugate was used for the detection of bison IgG.

scholarly journals Prospective Cohort Study of the Kinetics of Specific Antibodies to SARS-CoV-2 Infection and to Four SARS-CoV-2 Vaccines Available in Serbia, and Vaccine Effectiveness: A 3-Month Interim Report

Vaccines ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 1031
Author(s):  
Olivera Lijeskić ◽  
Ivana Klun ◽  
Marija Stamenov Djaković ◽  
Nenad Gligorić ◽  
Tijana Štajner ◽  
...  
Keyword(s):  
Real Life ◽  
Vaccine Dose ◽  
Igg Antibodies ◽  
Post Vaccination ◽  
Specific Antibodies ◽  
Real Life Data ◽  
Specific Igg ◽  
Antibody Levels ◽  
Kinetics Of ◽  
Specific Igg Antibodies

Real-life data on the performance of vaccines against SARS-CoV-2 are still limited. We here present the rates of detection and levels of antibodies specific for the SARS-CoV-2 spike protein RBD (receptor binding domain) elicited by four vaccines available in Serbia, including BNT-162b2 (BioNTech/Pfizer), BBIBP-CorV (Sinopharm), Gam-COVID-Vac (Gamaleya Research Institute) and ChAdOx1-S (AstraZeneca), compared with those after documented COVID-19, at 6 weeks and 3 months post first vaccine dose or post-infection. Six weeks post first vaccine dose, specific IgG antibodies were detected in 100% of individuals fully vaccinated with BNT-162b2 (n = 100) and Gam-COVID-Vac (n = 12) and in 81.7% of BBIBP-CorV recipients (n = 148), while one dose of ChAdOx1-S (n = 24) induced specific antibodies in 75%. Antibody levels elicited by BNT-162b2 were higher, while those elicited by BBIBP-CorV were lower, than after SARS-CoV-2 infection. By 3 months post-vaccination, antibody levels decreased but remained ≥20-fold above the cut-off in BNT-162b2 but not in BBIBP-CorV recipients, when an additional 30% were seronegative. For all vaccines, antibody levels were higher in individuals with past COVID-19 than in naïve individuals. A total of twelve new infections occurred within the first 3 months post-vaccination, eight after the first dose of BNT-162b2 and ChAdOx1-S (one each) and BBIBP-CorV (six), and four after full vaccination with BBIBP-CorV, but none required hospitalization.

scholarly journals IgM and IgG Immunoreactivity of SARS-CoV-2 Recombinant M Protein

2021 ◽  
Vol 22 (9) ◽  
pp. 4951
Author(s):  
Zorana Lopandić ◽  
Isidora Protić-Rosić ◽  
Aleksandra Todorović ◽  
Sofija Glamočlija ◽  
Marija Gnjatović ◽  
...  
Keyword(s):  
Immune Response ◽  
Virus Infection ◽  
Western Blot ◽  
Host Cells ◽  
M Protein ◽  
Terminal Part ◽  
Serum Samples ◽  
Specific Antibodies ◽  
Antigenic Properties ◽  
Specific Igg

Diagnostic evaluation of specific antibodies against the SARS-CoV-2 virus is mainly based on spike (S) and nucleocapsid (N) proteins. Despite the critical functions in virus infection and contribution to the pattern of immunodominance in COVID-19, exploitation of the most abundant membrane (M) protein in the SARS-CoV-2 serology tests is minimal. This study investigated the recombinant M protein’s immunoreactivity with the sera from COVID-19 convalescents. In silico designed protein was created from the outer N-terminal part (19 aa) and internal C-terminal tail (101–222 aa) of the M protein (YP_009724393.1) and was recombinantly produced and purified. The designed M protein (16,498.74 Da, pI 8.79) revealed both IgM and IgG reactivity with serum samples from COVID-19 convalescents in Western blot. In ELISA, more than 93% (28/30) of COVID-19 sera were positive for IgM detection, and more than 96% (29/30) were positive for specific IgG detection to M protein. Based on the capacity to provoke an immune response and its strong antigenic properties, as shown here, and the fact that it is also involved in the virion entry into host cells, the M protein of the SARS-CoV-2 virus as a good antigen has the potential in diagnostic purposes and vaccine design.

scholarly journals Human Milk from Previously COVID-19-Infected Mothers: The Effect of Pasteurization on Specific Antibodies and Neutralization Capacity

Nutrients ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 1645
Author(s):  
Britt J. van Keulen ◽  
Michelle Romijn ◽  
Albert Bondt ◽  
Kelly A. Dingess ◽  
Eva Kontopodi ◽  
...  
Keyword(s):  
Human Milk ◽  
Passive Immunization ◽  
Serum Samples ◽  
Specific Antibodies ◽  
Neutralization Capacity ◽  
N Protein ◽  
Unpasteurized Milk ◽  
Lactating Mothers ◽  
Neutralizing Capacity ◽  
Antibody Levels

Background: Since the outbreak of coronavirus disease 2019 (COVID-19), many put their hopes in the rapid availability of effective immunizations. Human milk, containing antibodies against syndrome coronavirus 2 (SARS-CoV-2), may serve as means of protection through passive immunization. We aimed to determine the presence and pseudovirus neutralization capacity of SARS-CoV-2 specific IgA in human milk of mothers who recovered from COVID-19, and the effect of pasteurization on these antibodies. Methods: This prospective case control study included lactating mothers, recovered from (suspected) COVID-19 and healthy controls. Human milk and serum samples were collected. To assess the presence of SARS-CoV-2 antibodies we used multiple complementary assays, namely ELISA with the SARS-CoV-2 spike protein (specific for IgA and IgG), receptor binding domain (RBD) and nucleocapsid (N) protein for IgG in serum, and bridging ELISA with the SARS-CoV-2 RBD and N protein for specific Ig (IgG, IgM and IgA in human milk and serum). To assess the effect of pasteurization, human milk was exposed to Holder (HoP) and High Pressure Pasteurization (HPP). Results: Human milk contained abundant SARS-CoV-2 antibodies in 83% of the proven cases and in 67% of the suspected cases. Unpasteurized milk with and without these antibodies was found to be capable of neutralizing a pseudovirus of SARS-CoV-2 in (97% and 85% of the samples respectively). After pasteurization, total IgA antibody levels were affected by HoP, while SARS-CoV-2 specific antibody levels were affected by HPP. Pseudovirus neutralizing capacity of the human milk samples was only retained with the HPP approach. No correlation was observed between milk antibody levels and neutralization capacity. Conclusions: Human milk from recovered COVID-19-infected mothers contains SARS-CoV-2 specific antibodies which maintained neutralization capacity after HPP. All together this may represent a safe and effective immunization strategy after HPP.

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