Effect of multiple freeze–thaw cycles on the detection of anti-SARS-CoV-2 IgG antibodies

Several studies have investigated the effect of repeated freeze–thaw (F/T) cycles on RNA detection for severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). However, no data are available regarding the effect of repeated F/T cycles on SARS-CoV-2 antibody detection in serum. We investigated the effect of multiple F/T cycles on anti-SARS-CoV-2 IgG detection using an ELISA test targeting the nucleocapsid antibodies. Ten positive and 1 negative SARS-CoV-2 IgG sera from 11 participants, in replicates of 5, were subjected to a total of 16 F/T cycles and stored at 4 °C until tested by ELISA. Statistical analysis was performed to test for F/T cycle effect. None of the 10 positive sera became negative after 16 F/T cycles. There was no significant difference in the OD average reading between the first and last F/T cycles, except for one serum with a minimal decline in the OD. The random effect linear regression of log (OD) on the number of cycles showed no significant trend, with a slope consistent with zero (B=−0.0001; 95 % CI −0.0008; 0.0006; P-value=0.781). These results suggest that multiple F/T cycles had no effect on the ability of the ELISA assay to detect SARS-CoV-2 IgG antibodies.

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Effect of multiple freeze-thaw cycles on detection of anti-SARS-CoV-2 IgG antibodies

10.1101/2021.04.13.21255379 ◽

2021 ◽

Author(s):

Farah M. Shurrab ◽

Duaa W. Al-Sadeq ◽

Fathima Amanullah ◽

Salma N. Younes ◽

Hadeel Al-Jighefee ◽

...

Keyword(s):

Random Effect ◽

Elisa Test ◽

Antibody Detection ◽

P Value ◽

Elisa Assay ◽

Igg Antibodies ◽

Rna Detection ◽

Freeze Thaw ◽

Significant Difference ◽

Number Of Cycles

AbstractSeveral studies have investigated the effect of repeated freeze-thaw (F/T) cycles on RNA detection for SARS-CoV-2. However, no data is available regarding the effect of repeated F/T cycles on SARS-CoV-2 antibody detection in serum. We investigated the effect of multiple F/T cycles on anti-SARS-CoV-2 IgG detection using an ELISA test targeting the nucleocapsid antibodies. Ten positive and one negative SARS-CoV-2 IgG sera from 11 participants, in replicates of five were subjected to a total of 16 F/T cycles and stored at 4°C until tested by ELISA. Statistical analysis was done to test for F/T cycle effect. Non-of the 10 positive sera turned into negative after 16 F/T cycles. There was no significant difference in the OD average reading between the first and last F/T cycles, except for one serum with a minimal decline in the OD. The random-effect linear regression of log (OD) on the number of cycles showed no significant trend with a slope consistent with zero (B=-0.0001; 95% CI −0.0008; 0.0006; p-value=0.781). These results suggest that multiple F/T cycles had no effect on the ability of the ELISA assay to detect the SARS-CoV-2 IgG antibodies.

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Investigation of Borrelia burgdorferi antibodies in patients with multiple sclerosis

Asian Journal of Medical Sciences ◽

10.3126/ajms.v11i2.27224 ◽

2020 ◽

Vol 11 (2) ◽

pp. 21-24

Author(s):

Nilay Ildız ◽

İbrahim Halil Özerol ◽

A. Cemal Özcan ◽

Hamit Çelik

Keyword(s):

Multiple Sclerosis ◽

Borrelia Burgdorferi ◽

Viral Infections ◽

Antibody Test ◽

Elisa Test ◽

Igg Antibodies ◽

Number Of Patients ◽

Seroprevalence Data ◽

Significant Difference ◽

Antibody Positivity

Background: Lyme is a disease that is non-compulsory in our country and whose seroprevalence data is less studied. Aims and Objective: Recent studies have shown that bacterial and viral infections are risk factor for various neurodegenerative diseases such as multiple sclerosis and Alzheimer’s disease. Herein, we aim to determine the seroprevalence of Lyme in multiple sclerosis (MS) patients. For this purpose, 100 MS patient’s serums were investigated for Borrelia burgdorferi IgM and IgG positivity. Materials and Methods: The results identified with ELISA as positive antibody was confirmed by Western Blot (WB) test. The correlation between ages, gender, occupation, tick history, existence of erythema chronicum migrans (ECM), antibody positivity, pain, year with MS results were investigated using Kolmogorov-Smirnow and Kruskal-Wallis statistical test. Results: B. burgdorferi IgM and IgG antibodies were positive in 8% patients when using ELISA method, but that were found to be 2% by WB. ELISA IgM antibody test gave a 5 negative result in WB. These results were considered false positive in the ELISA test. So, altogether 5 patients were positive by WB method. None of syphilis positive samples detected that B. burgdorferi positive serum. A significant difference between the parameters in terms of IgM positivity was not detected (p> 0.05). B. burgdorferi IgG antibodies were found significant differences between the MS disease duration (p = 0.03). MS in the group of less than 10 years had higher titers of IgG antibodies to B. burgdorferi. Conclusion: Although a small number of patients with MS is positive with Lyme antibodies. Lyme disease is a treatable.Also, If the patient is MS, clinician should be considered Lyme in the differential diagnosis. This is the first study that the correlation between Lyme and MS from Turkey.

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Highly Sensitive and Specific SARS-CoV-2 Serological Assay Using a Magnetic Modulation Biosensing System

Biosensors ◽

10.3390/bios12010007 ◽

2021 ◽

Vol 12 (1) ◽

pp. 7

Author(s):

Shira Avivi-Mintz ◽

Yaniv Lustig ◽

Victoria Indenbaum ◽

Eli Schwartz ◽

Amos Danielli

Keyword(s):

Viral Infections ◽

Limit Of Detection ◽

Turnaround Time ◽

Elisa Test ◽

Antibody Detection ◽

Enzyme Linked Immunosorbent Assay ◽

Igg Antibodies ◽

Serological Assay ◽

Clinical Sensitivity ◽

Highly Sensitive

Sensitive serological assays are needed to provide valuable information about acute and past viral infections. For example, detection of anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) IgG antibodies could serve as the basis for an “immunity passport” that would enable individuals to travel internationally. Here, utilizing a novel Magnetic Modulation Biosensing (MMB) system and the receptor-binding domain of the SARS-CoV-2 spike protein, we demonstrate a highly sensitive and specific anti-SARS-CoV-2 IgG serological assay. Using anti-SARS-CoV-2 IgG antibodies, RT-qPCR SARS-CoV-2-positive and healthy patients’ samples, and vaccinees’ samples, we compare the MMB-based SARS-CoV-2 IgG assay’s analytical and clinical sensitivities to those of the enzyme-linked immunosorbent assay (ELISA). Compared with ELISA, the MMB-based assay has an ~6-fold lower limit of detection (129 ng/L vs. 817 ng/L), and it detects an increase in the IgG concentration much earlier after vaccination. Using 85 RT-qPCR SARS-CoV-2-positive samples and 79 -negative samples, the MMB-based assay demonstrated similar clinical specificity (98% vs. 99%) and sensitivity (93% vs. 92%) to the ELISA test, but with a much faster turnaround time (45 min vs. 245 min). The high analytical and clinical sensitivity, short turnaround time, and simplicity of the MMB-based assay makes it a preferred method for antibody detection.

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Analysis of IgG, IgA, and IgM antibodies against SARS-CoV-2 spike protein S1 in convalescent and vaccinated patients with the Pfizer-BioNTech and CanSinoBio vaccines

10.22541/au.162713826.67558372/v1 ◽

2021 ◽

Author(s):

Edgar Melgoza-González ◽

Diana Hinojosa-Trujillo ◽

Monica Resendiz ◽

Verónica Mata-Haro ◽

Sofía Hernández-Valenzuela ◽

...

Keyword(s):

Indirect Elisa ◽

Natural Infection ◽

Rapid Development ◽

Elisa Test ◽

Antibody Detection ◽

Diagnostic Tools ◽

Igg Antibodies ◽

The World ◽

The One ◽

First Time

The SARS-CoV-2 virus was detected for the first time in December 2019 in Wuhan, China. Currently, this virus has spread around the world, and new variants have emerged. This new pandemic virus provoked the rapid development of diagnostic tools, therapies and vaccines to control this new disease called COVID-19. Antibody detection by ELISA has been broadly used to recognize the number of persons infected with this virus or to evaluate the response of vaccinated individuals. As the pandemic spread, new questions arose, such as the prevalence of antibodies after natural infection and the response induced by the different vaccines. In Mexico, as in other countries, mRNA and viral-vectored vaccines have been widely used among the population. In this work, we developed an indirect ELISA test to evaluate S1 antibodies in convalescent and vaccinated individuals. By using this test, we showed that IgG antibodies against the S1 protein of SARS-CoV-2 were detected up to 42 weeks after the onset of the symptoms, in contrast to IgA and IgM, which decreased 14 weeks after the onset of symptoms. The evaluation of the antibody response in individuals vaccinated with Pfizer-BioNTech and CanSinoBio vaccines showed no differences two weeks after vaccination. However, after completing the two doses of Pfizer-BioNTech and the one dose of CanSinoBio, a significantly higher response of IgG antibodies was observed in persons vaccinated with Pfizer-BioNTech than in those vaccinated with CanSinoBio. In conclusion, these results confirm that after natural infection with SARS-CoV-2, it is possible to detect antibodies for up to ten months. Additionally, our results showed that one dose of the CanSinoBio vaccine induces a lower response of IgG antibodies than that induced by the complete scheme of the Pfizer-BioNTech vaccine.

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Identification of toxocara canis antigens by Western blot in experimentally infected rabbits

Revista do Instituto de Medicina Tropical de São Paulo ◽

10.1590/s0036-46652002000400006 ◽

2002 ◽

Vol 44 (4) ◽

pp. 213-216 ◽

Cited By ~ 10

Author(s):

Olga Lucía MORALES ◽

Myriam Consuelo LÓPEZ ◽

Rubén Santiago NICHOLLS ◽

Carlos AGUDELO

Keyword(s):

Western Blot ◽

Toxocara Canis ◽

Diagnostic Techniques ◽

Elisa Test ◽

Elisa Assay ◽

Secondary Antibody ◽

Igg Antibodies ◽

Specific Antibodies ◽

Second Stage ◽

Specific Antigens

Toxocariasis is a frequent helminthiasis that can cause visceral and ocular damage in humans specially in children. The identification of specific antigens of Toxocara canis is important in order to develop better diagnostic techniques. Ten rabbits were infected orally with a dose of 5000 Toxocara canis embryonated eggs. Rabbits were bled periodically and an ELISA assay was performed to determine levels of specific Toxocara IgG antibodies. ELISA detected antibodies at day 15 after infection. Western blot (WB) assay was performed using excretory/secretory antigens (E/S) of T. canis second stage larvae. Different antigen concentrations were evaluated: 150, 200, 250 and 300 µg/mL. The concentration of 250 µg/mL was retained for analysis. Rabbit sera were diluted 1:100. Secondary antibody was used at a dilution of 1:1000. Results of WB indicated that in the first month after infection specific antibodies against the 200 KDa, 116 KDa, 92 KDa and 35 KDa antigens were detected; antibodies against the 92 KDa, 80 KDa, 66 KDa, 45 KDa, 31 KDa and 28 KDa antigens appeared later. All positive sera in the ELISA test were also positive in WB. Two antigen bands, 92 KDa and 35 KDa, were identified since the beginning and throughout the course of infection. These antigens merit further evaluation as candidates for use in diagnosis.

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Crimean-Congo haemorrhagic fever (CCHF) virus-specific antibody detection in blood donors, Castile-León, Spain, summer 2017 and 2018

Eurosurveillance ◽

10.2807/1560-7917.es.2020.25.10.1900507 ◽

2020 ◽

Vol 25 (10) ◽

Author(s):

Lía Monsalve Arteaga ◽

Juan Luis Muñoz Bellido ◽

María Carmen Vieira Lista ◽

María Belén Vicente Santiago ◽

Pedro Fernández Soto ◽

...

Keyword(s):

Rural Areas ◽

Blood Donors ◽

Animal Husbandry ◽

Elisa Test ◽

Antibody Detection ◽

Haemorrhagic Fever ◽

Igg Antibodies ◽

Cross Sectional ◽

Crimean Congo Haemorrhagic Fever ◽

Western Spain

Background Crimean-Congo haemorrhagic fever virus (CCHFV) is considered an emerging or even a probable re-emerging pathogen in southern Europe. Presence of this virus had been reported previously in Spain in 2010. Aim We aimed to evaluate the potential circulation of CCHFV in western Spain with a serosurvey in asymptomatic adults (blood donors). Methods During 2017 and 2018, we conducted a CCHFV serosurvey in randomly selected asymptomatic blood donors from western Spain. Three assays using specific IgG antibodies against CCHFV were performed: the VectoCrimea ELISA test, an in-house ELISA and indirect immunofluorescence (EuroImmun) test with glycoprotein and nucleoprotein. Results A total of 516 blood donors participated in this cross-sectional study. The majority of the study participants were male (68.4%), and the mean age was 46.3 years. Most of the participants came from rural areas (86.8%) and 68.6% had contact with animals and 20.9% had animal husbandry practices. One in five participants (109/516, 21.1%) were engaged in at-risk professional activities such as agriculture and shepherding, slaughtering, hunting, veterinary and healthcare work (mainly nursing staff and laboratory technicians). A total of 15.3% of the participants were bitten by ticks in the days or months before the date of sampling. We detected anti-CCHFV IgG antibodies with two diagnostic assays in three of the 516 individuals and with one diagnostic assay in six of the 516 individuals. Conclusion Seroprevalence of CCHFV was between 0.58% and 1.16% in Castile-León, Spain. This is the first study in western Spain that showed circulation of CCHFV in healthy people.

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Application of Food-specific IgG Antibody Detection in Allergy Dermatosis

Open Medicine ◽

10.1515/med-2015-0067 ◽

2015 ◽

Vol 10 (1) ◽

Cited By ~ 1

Author(s):

Hu Yine ◽

Dai Shufang ◽

Wang Bin ◽

Qu Wei ◽

Muhammad Aqeel Ashraf ◽

...

Keyword(s):

Antibody Detection ◽

Igg Antibodies ◽

Igg Antibody ◽

Allergic Dermatitis ◽

Positive Antibody ◽

Significant Difference ◽

Positive Rate ◽

High Incidence Rate ◽

Specific Igg ◽

Specific Igg Antibodies

AbstractThe application of food-specific IgG antibody detection in allergy dermatoses was explored. 181 patients with allergy dermatoses were diagnosed from January to September 2014 and 20 healthy subjects were selected. Fourteen kinds of food-specific IgG antibodies were detected by ELISA method among all the subjects. The positive rates of IgG antibody of the patient group and the healthy group were respectively 65.2% and 5.0%. The positive rates of IgG antibody of egg, milk, shrimp and crab took a large proportion in three groups of patients with three kinds of allergy dermatoses of urticaria, eczema and allergic dermatitis, the proportion of which was respectively 70.2%, 77.8% and 71.7%. Among urticaria and allergic dermatitis patients with positive antibody, the positive rate of children was significantly higher than that of adults (p<0.05) while there was no significant difference between children and adults among eczema patients with positive antibody (p>0.05). Allergy dermatoses are closely related to food-specific IgG antibodies, and the allergy dermatoses patients have a high incidence rate of food intolerance; detecting IgG antibody in the serum of patients is of great significance for the diagnosis and treatment of allergy dermatoses.

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Characteristics of erythropoietin antibodies in patients treated with recombinant human erythropoietin

Medical Immunology (Russia) ◽

10.15789/1563-0625-coe-1879 ◽

2020 ◽

Vol 22 (1) ◽

pp. 143-152

Author(s):

A. M. Kudryashova ◽

L. N. Nesterenko ◽

G. A. Generalova ◽

T. Yu. Abasheeva ◽

N. A. Mikhailova ◽

...

Keyword(s):

Detection Limit ◽

Polyclonal Antibodies ◽

Protein A ◽

Elisa Test ◽

Antibody Detection ◽

Quantitative Detection ◽

Antibody Concentration ◽

Igg Antibodies ◽

Serum Samples ◽

Igg Antibody

Our aim was to characterize anti-EPO antibodies in serum samples of the patients treated with erythropoietin. 106 serum samples from the patients treated with erythropoietin (EPO) were collected and assayed. 134 serum samples of patients who did not receive EPO were taken for comparative analysis. The anti-EPO antibody detection was performed in ELISA test with rhEPO, by passive capture on ELISA plates, using steptavidin-biotin immunochemical system. Mouse monoclonal antibodies to human IgG, IgG1, IgG2, IgG3 and IgG4 conjugated to horseradish peroxidase were used to detect anti-EPO antibodies, and protein-A peroxidase conjugate was used for quantitative assays. Rabbit anti-human EPO polyclonal antibodies at known concentrations were used as a calibration standard. Six calibration samples at the concentration range of 16-1000 ng/ml were used to plot calibration curves. The lower detection limit was 12 ng/mL, and the quantitative detection limit was 31 ng/ml. Immunochemical capturing led to increasing of total IgG antibody detection by 3.2 times, IgG1 – by 1.1 times IgG2 – by 1.25 times, IgG3 – by 1.5 times, IgG4 – by 1.7 times. Antibodies of mixed isotype were found in most patients. IgG1 or IgG4 antibodies to EPO were determined only in 3 samples. Specific IgM was not detectable among 106 sera samples, whereas total IgG antibodies were detected in 36.8 % of cases. In 34% of sera, their presence was confirmed by detection of at least one of the subclasses. IgG1 antibody was detected in 83.3%; IgG4, in 80.6% of the samples positive for total IgG antibodies. In all cases, IgG2 and/or IgG3 were detected in presence of IgG1 or IgG4 antibodies. The antibody concentration was 3.2 to 35.5 µg/mL in sera from 28 patients, in 8 cases the level of antibodies was > 50 µg/ml, however, being below the limit of quantitative detection in 3 patients. Only 6 samples contained antibodies with avidity index of > 50%. Immunochemical capturing of the antigen led to increased sensitivity for detecting all subclasses of specific antibodies. The specific IgG antibodies to EPO were found in more than 1/3 of serum samples from the patients treated with erythropoietin. Low-avidity antibodies of IgG1 and IgG4 subclasses were determined in most cases.

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No evidence of significant cross-reactivity between the dengue virus (DENV) and SARS-CoV-2 IgG antibodies

10.1101/2021.04.19.21255725 ◽

2021 ◽

Author(s):

Farah M. Shurrab ◽

Fatima Humaira ◽

Enas S. Al-Absi ◽

Duaa W. Al-Sadeq ◽

Hamda Qotba ◽

...

Keyword(s):

Dengue Virus ◽

Study Design ◽

Point Of Care ◽

Cross Reactivity ◽

P Value ◽

Elisa Assay ◽

Igg Antibodies ◽

Limited Data ◽

Chemiluminescence Immunoassay ◽

Significant Difference

AbstractBackgroundSeveral studies reported serological cross-reaction between DENV and SARS-CoV-2 IgG antibodies using rapid point of care (POC) assays. Limited data are available about cross-reactivity when testing is done using advanced chemiluminescence immunoassay (CLIA) and ELISA assays.ObjectiveThis study aims to investigate potential serological cross-reactivity between SARS-CoV-2-IgG and DENV-IgG using CLIA and ELISA assays.Study-designA total of 90 DENV-IgG-ELISA positive and 90 negative pre-pandemic sera were tested for anti-SARS-CoV-2-IgG using the automated CL-900i CLIA assay. Furthermore, a total of 91 SARS-CoV-2-IgG-CLIA positive and 91 negative post-pandemic sera were tested for anti-DENV-IgG using the Novalis ELISA assay.ResultsThe DENV-IgG positive sera had 5 positives and 85 negatives for SARS-CoV-2-IgG. The DENV-IgG negative sera also had 5 positives and 85 negatives for SARS-CoV-2-IgG. No statistically significant difference in specificity between the DENV-IgG positive and DENV-IgG negative sera was found (p-value=1.00). The SARS-CoV-2-IgG positive sera had 43 positives, 47 negatives, and 1 equivocal for DENV-IgG. The SARS-CoV-2-IgG negative sera had 50 positives, 40 negatives, and 1 equivocal for DENV-IgG. No statistically significant difference in the proportion that is DENV-IgG positive between the SARS-CoV-2-IgG positive and SARS-CoV-2-IgG negative sera (p-value=0.58).ConclusionsNo evidence for cross-reactivity between the DENV and SARS-CoV-2 IgG antibodies was found.

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Serological screening of patients with clinical suspicion of trichinellosis in Belgrade from 2009 to 2018

Veterinarski glasnik ◽

10.2298/vetgl190311014d ◽

2019 ◽

Vol 73 (2) ◽

pp. 144-156

Author(s):

Zorica Dakic ◽

Nikola Mitrovic ◽

Snezana Jovanovic ◽

Branko Milosevic ◽

Ivana Milosevic ◽

...

Keyword(s):

Elisa Test ◽

Cross Reactivity ◽

Antibody Detection ◽

Parasitic Infections ◽

Igg Antibodies ◽

Clinical Center ◽

Hospitalised Patients ◽

Number Of Patients ◽

Specific Igg ◽

Specific Igg Antibodies

Introduction. Trichinellosis is one of the most important foodborne diseases in Serbia. Most patients with suspected trichinellosis in Belgrade are referred to the Clinical Center of Serbia for diagnosis and treatment, as are unclear and complicated cases from all across Serbia. Materials and Methods. A retrospective study of trichinellosis serology was carried out from 2009-2018 and included all outpatients and hospitalised patients from the Clinic for Infectious and Tropical Disease, Clinical Center of Serbia, who were serologically tested for Trichinella by the Parasitological Laboratory (n=1,565). Trichinella-specific IgG antibodies were detected in sera by a commercial ELISA test. We analysed the seroprevalence of Trichinella-specific IgG antibodies, antibody detection kinetics and cross-reactivity with other nematodes. Results and Conclusions. The number of patients who reported for serological testing varied greatly per year and month. Most patients were tested in December and March, which coincides with the months with the most confirmed cases of trichinellosis. A total of 17.4% patients who were tested for trichinellosis had other parasitic infections. Altogether, 223 (14.2%) of tested patients were finally diagnosed with trichinellosis. We detected anti-Trichinella IgG in 68.8% (223) of patients with suspected trichinellosis on admission, which increased to 86.5%, 91.5% and 92.4% after later second, third and fourth testing, respectively. Final diagnoses of toxocariasis, strongyloidiasis, filariasis, and dirofilariasis were made for 2.4%, 0.3%, 0.3% and 0.1% of patients, respectively. Concurrent seropositivity for Trichinella and Toxocara was observed in 18.9% (7/37) of patients with clinical presentation of trichinellosis and who were also tested for toxocariasis. In 3/5 patients with imported filariasis, we found cross-reactivity with Trichinella. Potential cross-reactivity of this ELISA test with antibodies to the autochthonous nematode Toxocara canis demands the introduction of Western blot technology. Trichinellosis must be diagnosed by the combination of clinical, laboratory and epidemiological criteria.

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