Aptamer BC 007’s Affinity to Specific and Less-Specific Anti-SARS-CoV-2 Neutralizing Antibodies

COVID-19 is a pandemic respiratory disease that is caused by the highly infectious severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Anti-SARS-CoV-2 antibodies are essential weapons that a patient with COVID-19 has to combat the disease. When now repurposing a drug, namely an aptamer that interacts with SARS-CoV-2 proteins for COVID-19 treatment (BC 007), which is, however, a neutralizer of pathogenic autoantibodies in its original indication, the possibility of also binding and neutralizing anti-SARS-CoV-2 antibodies must be considered. Here, the highly specific virus-neutralizing antibodies have to be distinguished from the ones that also show cross-reactivity to tissues. The last-mentioned could be the origin of the widely reported SARS-CoV-2-induced autoimmunity, which should also become a target of therapy. We, therefore, used enzyme-linked immunosorbent assay (ELISA) technology to assess the binding of well-characterized publicly accessible anti-SARS-CoV-2 antibodies (CV07-209 and CV07-270) with BC 007. Nuclear magnetic resonance spectroscopy, isothermal calorimetric titration, and circular dichroism spectroscopy were additionally used to test the binding of BC 007 to DNA-binding sequence segments of these antibodies. BC 007 did not bind to the highly specific neutralizing anti-SARS-CoV-2 antibody but did bind to the less specific one. This, however, was a lot less compared to an autoantibody of its original indication (14.2%, range 11.0–21.5%). It was also interesting to see that the less-specific anti-SARS-CoV-2 antibody also showed a high background signal in the ELISA (binding on NeutrAvidin-coated or activated but noncoated plastic plate). These initial experiments suggest that the risk of binding and neutralizing highly specific anti-SARS CoV-2 antibodies by BC 007 should be low.

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Isolation of Human Monoclonal Antibodies That Neutralize Human Rotavirus

Journal of Virology ◽

10.1128/jvi.78.7.3325-3332.2004 ◽

2004 ◽

Vol 78 (7) ◽

pp. 3325-3332 ◽

Cited By ~ 26

Author(s):

Kyoko Higo-Moriguchi ◽

Yasushi Akahori ◽

Yoshitaka Iba ◽

Yoshikazu Kurosawa ◽

Koki Taniguchi

Keyword(s):

Neutralizing Antibodies ◽

Cross Reactivity ◽

Amino Acid Sequences ◽

Enzyme Linked Immunosorbent Assay ◽

Human Antibody ◽

Display System ◽

Neutralizing Activity ◽

Human Antibodies ◽

Human Rotavirus ◽

Human Specific

ABSTRACT A human antibody library constructed by utilizing a phage display system was used for the isolation of human antibodies with neutralizing activity specific for human rotavirus. In the library, the Fab form of an antibody fused to truncated cp3 is expressed on the phage surface. Purified virions of strain KU (G1 serotype and P[8] genotype) were used as antigen. Twelve different clones were isolated. Based on their amino acid sequences, they were classified into three groups. Three representative clones—1-2H, 2-3E, and 2-11G—were characterized. Enzyme-linked immunosorbent assay with virus-like particles (VLP-VP2/6 and VLP-VP2/6/7) and recombinant VP4 protein produced from baculovirus recombinants indicated that 1-2H and 2-3E bind to VP4 and that 2-11G binds to VP7. The neutralization epitope recognized by each of the three human antibodies might be human specific, since all of the antigenic mutants resistant to mouse monoclonal neutralizing antibodies previously prepared were neutralized by the human antibodies obtained here. After conversion from the Fab form of an antibody into immunoglobulin G1, the neutralizing activities of these three clones toward various human rotavirus strains were examined. The 1-2H antibody exhibited neutralizing activity toward human rotaviruses with either the P[4] or P[8] genotype. Similarly, the 2-3E antibody showed cross-reactivity against HRVs with the P[6], as well as the P[8] genotype. In contrast, the 2-11G antibody neutralized only human rotaviruses with the G1 serotype. The concentration of antibodies required for 50% neutralization ranged from 0.8 to 20 μg/ml.

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trans-Sialidase Neutralizing Antibody Detection in Trypanosoma cruzi-Infected Domestic Reservoirs

Clinical and Vaccine Immunology ◽

10.1128/cvi.00535-10 ◽

2011 ◽

Vol 18 (6) ◽

pp. 984-989 ◽

Cited By ~ 8

Author(s):

Paula A. Sartor ◽

Martha V. Cardinal ◽

Marcela M. Orozco ◽

Ricardo E. Gürtler ◽

M. Susana Leguizamón

Keyword(s):

Visceral Leishmaniasis ◽

Trypanosoma Cruzi ◽

Neutralizing Antibodies ◽

Cross Reactivity ◽

Antibody Detection ◽

Enzyme Linked Immunosorbent Assay ◽

Trypanosoma Rangeli ◽

Serum Samples ◽

Dipstick Test ◽

Content Type

ABSTRACTThe detection ofTrypanosoma cruziinfection in domestic dogs and cats is relevant to evaluating human transmission risks and the effectiveness of insecticide spraying campaigns. However, the serological assays routinely used are associated with cross-reactivity in sera from mammals infected withLeishmaniaspp. We used atrans-sialidase inhibition assay (TIA) forT. cruzidiagnosis in serum samples from 199 dogs and 57 cats from areas where these types of infections are endemic. TIA is based on the antibody neutralization of recombinanttrans-sialidase, an enzyme that is not detected in the coendemicLeishmaniaspecies orTrypanosoma rangeliparasites.T. cruziinfection was also evaluated by conventional serology (CS) (indirect immunofluorescence, indirect hemagglutination, enzyme-linked immunosorbent assay, and immunochromatographic dipstick test) and xenodiagnosis. Sera from 30 dogs and 15 cats from areas where these organisms are not endemic and 5 dogs with visceral leishmaniasis were found to be nonreactive by TIA and CS. Samples from dogs and cats demonstrated 91 and 95% copositivities between TIA and CS, whereas the conegativities were 98 and 97%, respectively. Sera from xenodiagnosis-positive dogs and cats also reacted by TIA (copositivities of 97 and 83%, respectively). TIA was reactive in three CS-negative samples and was able to resolve results in two cat serum samples that were CS inconclusive. Our study is the first to describe the development oftrans-sialidase neutralizing antibodies in naturally infected dogs and cats. High CS conegativity and the absence oftrans-sialidase neutralization in dog sera from areas where leishmaniasis is not endemic and from dogs with visceral leishmaniasis support TIA specificity. The TIA may be a useful tool forT. cruzidetection in the main domestic reservoirs.

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SARS-CoV-2 neutralizing serum antibodies in cats: a serological investigation

10.1101/2020.04.01.021196 ◽

2020 ◽

Cited By ~ 46

Author(s):

Qiang Zhang ◽

Huajun Zhang ◽

Kun Huang ◽

Yong Yang ◽

Xianfeng Hui ◽

...

Keyword(s):

Neutralizing Antibodies ◽

Cross Reactivity ◽

Enzyme Linked Immunosorbent Assay ◽

Type I ◽

Receptor Binding Domain ◽

Serum Antibodies ◽

Serum Samples ◽

Susceptible Animal ◽

Feline Infectious Peritonitis ◽

Specific Serum

SummaryCoronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was first reported in Wuhan, China, and rapidly spread worldwide. Previous studies suggested cat could be a potential susceptible animal of SARS-CoV-2. Here, we investigated the infection of SARS-CoV-2 in cats by detecting specific serum antibodies. A cohort of serum samples were collected from cats in Wuhan, including 102 sampled after COVID-19 outbreak, and 39 prior to the outbreak. 15 of 102 (14.7%) cat sera collected after the outbreak were positive for the receptor binding domain (RBD) of SARS-CoV-2 by indirect enzyme linked immunosorbent assay (ELISA). Among the positive samples, 11 had SARS-CoV-2 neutralizing antibodies with a titer ranging from 1/20 to 1/1080. No serological cross-reactivity was detected between the SARS-CoV-2 and type I or II feline infectious peritonitis virus (FIPV). Our data demonstrates that SARS-CoV-2 has infected cat population in Wuhan during the outbreak.

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753. Performance Characteristics of Diagnostic Assays in Blastomycosis

Open Forum Infectious Diseases ◽

10.1093/ofid/ofaa439.943 ◽

2020 ◽

Vol 7 (Supplement_1) ◽

pp. S424-S424

Author(s):

Timothy O’Dowd ◽

Jack McHugh ◽

Nancy Wengenack ◽

Elitza Theel ◽

Paschalis Vergidis

Keyword(s):

Granulomatous Inflammation ◽

Cross Reactivity ◽

Performance Characteristics ◽

Enzyme Linked Immunosorbent Assay ◽

Fungal Culture ◽

Noninvasive Test ◽

Serum Antigen ◽

Urine Antigen ◽

Antigen Tests ◽

Urine And Serum

Abstract Background Blastomycosis has historically been a difficult diagnosis to establish, often initially misdiagnosed as bacterial pneumonia. Serologic assays and polymerase chain reaction (PCR) tests are available, but their performance is not well defined. The objective of this study was to characterize their performance. Methods Subjects were identified via chart review of patients diagnosed with blastomycosis from 2005 to 2020. A definitive diagnosis was based on fungal culture, histopathology, or cytology. Performance characteristics of the Blastomyces antibody enzyme linked immunosorbent assay (ELISA), immunodiffusion (ID), complement fixation (CF), urine and serum antigen ELISAs, and PCR were evaluated in patients with confirmed blastomycosis. Data on patient demographics, location of disease, and mortality was also collected. Results We identified 193 patients with blastomycosis. The mean age was 51.8 years (range, 11-84) and 73.6% of patients were male. 42.5% resided in Minnesota, 18.1% in Wisconsin, and 12.9% in Iowa. Diagnosis was based on culture in 142 (73.2%) or histopathology/cytology in 67 (34.7%) patients. Granulomatous inflammation was present in 73.1% (38/52) while 21.2% (41/193) had evidence of extrapulmonary dissemination. The antibody, ID, and CF assays were positive in 43.5% (37/85), 35.1% (33/94) and 20.5% (8/39) of patients, respectively. Sensitivity of Blastomyces PCR was 40% (4/10) in sputum and 75% (21/28) in bronchoalveolar lavage (BAL) fluid. Blastomyces urine and serum antigen tests were positive in 68% (34/50) and 50% (9/18) of cases, respectively, while the urine antigen was positive in 63.6% (7/11) of disseminated cases. Patients had a positive Histoplasma urine antigen test in 54.1% (20/37) and Aspergillus galactomannan in BAL in 34.8% (8/23) of cases. Serum beta-D-glucan test was positive in 16.7% (2/12). 90-day mortality was 21/193 (10.9%) and median time from diagnosis to death was 18 days. Conclusion In this cohort, Blastomyces urine antigen was the most sensitive noninvasive test, with similar performance in pulmonary and disseminated disease. However, its utility is limited by poor specificity due to cross-reactivity. Blastomyces PCR from BAL fluid demonstrated the highest sensitivity. Blastomyces antibody, ID, and CF had poor sensitivity. Disclosures All Authors: No reported disclosures

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Characterization of the Diagnostic Performance of a Novel COVID-19 PETIA in Comparison to Four Routine N-, S- and RBD-Antigen Based Immunoassays

Diagnostics ◽

10.3390/diagnostics11081332 ◽

2021 ◽

Vol 11 (8) ◽

pp. 1332

Author(s):

Alexander Spaeth ◽

Thomas Masetto ◽

Jessica Brehm ◽

Leoni Wey ◽

Christian Kochem ◽

...

Keyword(s):

Immune Response ◽

Cross Reactivity ◽

Enzyme Linked Immunosorbent Assay ◽

Chemiluminescence Immunoassay ◽

Face To Face ◽

Comprehensive Comparison ◽

Broad Variety ◽

Viral Responses ◽

Novel Coronavirus ◽

High Consistency

In 2019, a novel coronavirus emerged in Wuhan in the province of Hubei, China. The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) quickly spread across the globe, causing the neoteric COVID-19 pandemic. SARS-CoV-2 is commonly transmitted by droplet infection and aerosols when coughing or sneezing, as well as high-risk exposures to infected individuals by face-to-face contact without protective gear. To date, a broad variety of techniques have emerged to assess and quantify the specific antibody response of a patient towards a SARS-CoV-2 infection. Here, we report the first comprehensive comparison of five different assay systems: Enzyme-Linked Immunosorbent Assay (ELISA), Chemiluminescence Immunoassay (CLIA), Electro-Chemiluminescence Immunoassay (ECLIA), and a new Particle-Enhanced Turbidimetric Immunoassay (PETIA) for SARS-CoV-2. Furthermore, we also evaluated the suitability of N-, S1- and RBD-antigens for quantifying the SARS-CoV-2 specific immune response. Linearity and precision, overall sensitivity and specificity of the assays, stability of samples, and cross-reactivity of general viral responses, as well as common coronaviruses, were assessed. Moreover, the reactivity of all tests to seroconversion and different sample matrices was quantified. All five assays showed good overall agreement, with 76% and 87% similarity for negative and positive samples, respectively. In conclusion, all evaluated methods showed a high consistency of results and suitability for the robust quantification of the SARS-CoV-2-derived immune response.

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SARS-CoV-2 IgG Antibodies Seroprevalence and Sera Neutralizing Activity in MEXICO: A National Cross-Sectional Study during 2020

Microorganisms ◽

10.3390/microorganisms9040850 ◽

2021 ◽

Vol 9 (4) ◽

pp. 850

Author(s):

José Esteban Muñoz-Medina ◽

Concepción Grajales-Muñiz ◽

Angel Gustavo Salas-Lais ◽

Larissa Fernandes-Matano ◽

Constantino López-Macías ◽

...

Keyword(s):

Immunosorbent Assay ◽

Neutralizing Antibodies ◽

Herd Immunity ◽

Cross Sectional Study ◽

Molecular Techniques ◽

Diagnostic Methods ◽

Molecular Diagnostic ◽

Enzyme Linked Immunosorbent Assay ◽

Cross Sectional ◽

Neutralizing Activity

Until recently, the incidence of COVID-19 was primarily estimated using molecular diagnostic methods. However, the number of cases is vastly underreported using these methods. Seroprevalence studies estimate cumulative infection incidences and allow monitoring of transmission dynamics, and the presence of neutralizing antibodies in the population. In February 2020, the Mexican Social Security Institute began conducting anonymous unrelated sampling of residual sera from specimens across the country, excluding patients with fever within the previous two weeks and/or patients with an acute respiratory infection. Sampling was carried out weekly and began 17 days before Mexico’s first officially confirmed case. The 24,273 sera obtained were analyzed by chemiluminescent-linked immunosorbent assay (CLIA) IgG S1/S2 and, later, positive cases using this technique were also analyzed to determine the rate of neutralization using the enzyme-linked immunosorbent assay (ELISA). We identified 40 CLIA IgG positive cases before the first official report of SARS-CoV-2 infection in Mexico. The national seroprevalence was 3.5% in February and 33.5% in December. Neutralizing activity among IgG positives patients during overall study period was 86.1%. The extent of the SARS-CoV-2 infection in Mexico is 21 times higher than that reported by molecular techniques. Although the general population is still far from achieving herd immunity, epidemiological indicators should be re-estimated based on serological studies of this type.

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Dogs as Sentinels for Flavivirus Exposure in Urban, Peri-Urban and Rural Hanoi, Vietnam

Viruses ◽

10.3390/v13030507 ◽

2021 ◽

Vol 13 (3) ◽

pp. 507

Author(s):

Long Pham-Thanh ◽

Thang Nguyen-Tien ◽

Ulf Magnusson ◽

Vuong Bui-Nghia ◽

Anh Bui-Ngoc ◽

...

Keyword(s):

Mosquito Control ◽

Risk Mitigation ◽

Significant Risk ◽

Cross Sectional Study ◽

Cross Reactivity ◽

Enzyme Linked Immunosorbent Assay ◽

Serum Samples ◽

Cross Sectional ◽

Major Health ◽

Household Level

Diseases caused by flaviviruses, including dengue fever and Japanese encephalitis, are major health problems in Vietnam. This cross-sectional study explored the feasibility of domestic dogs as sentinels to better understand risks of mosquito-borne diseases in Hanoi city. A total of 475 dogs serum samples from 221 households in six districts of Hanoi were analyzed by a competitive enzyme-linked immunosorbent assay (cELISA) for antibodies to the pr-E protein of West Nile virus and other flaviviruses due to cross-reactivity. The overall flavivirus seroprevalence in the dog population was 70.7% (95% CI = 66.4–74.8%). At the animal level, significant associations between seropositive dogs and district location, age, breed and keeping practice were determined. At the household level, the major risk factors were rural and peri-urban locations, presence of pigs, coil burning and households without mosquito-borne disease experience (p < 0.05). Mosquito control by using larvicides or electric traps could lower seropositivity, but other measures did not contribute to significant risk mitigation of flavivirus exposure in dogs. These results will support better control of mosquito-borne diseases in Hanoi, and they indicate that dogs can be used as sentinels for flavivirus exposure.

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Immune Evasion of SARS-CoV-2 Variants of Concern is Driven by Low Affinity to Neutralizing Antibodies

Chemical Communications ◽

10.1039/d1cc01747k ◽

2021 ◽

Author(s):

Matheus Ferraz ◽

Emerson Moreira ◽

Danilo F. Coêlho ◽

Gabriel Wallau ◽

Roberto Lins

Keyword(s):

Immune Evasion ◽

Neutralizing Antibodies ◽

Cross Reactivity ◽

Class I ◽

Minor Role ◽

A Minor

SARS-CoV-2 VOCs immune evasion is mainly due to lower cross-reactivity from previously elicited class I/II neutralizaing antibodies, while increased affinity to hACE2 plays a minor role. Affinity between antibodies and...

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Viral Protein VP4 Is a Target of Human Antibodies Enhancing Coxsackievirus B4- and B3-Induced Synthesis of Alpha Interferon

Journal of Virology ◽

10.1128/jvi.79.22.13882-13891.2005 ◽

2005 ◽

Vol 79 (22) ◽

pp. 13882-13891 ◽

Cited By ~ 32

Author(s):

Wassim Chehadeh ◽

Pierre-Emmanuel Lobert ◽

Pierre Sauter ◽

Anne Goffard ◽

Bernadette Lucas ◽

...

Keyword(s):

Healthy Subjects ◽

Neutralizing Antibodies ◽

Mononuclear Cells ◽

Insulin Dependent Diabetes Mellitus ◽

Alpha Interferon ◽

Dependent Diabetes Mellitus ◽

Enzyme Linked Immunosorbent Assay ◽

Peripheral Blood Mononuclear ◽

Coxsackievirus B4

ABSTRACT Coxsackievirus B4 (CVB4)-induced production of alpha interferon (IFN-α) by peripheral blood mononuclear cells (PBMC) is enhanced in vitro by nonneutralizing anti-CVB4 antibodies from healthy subjects and, to a higher extent, from patients with insulin-dependent diabetes mellitus. In this study, we focused on identification of the viral target of these antibodies in CVB systems. High levels of IFN-α were obtained in supernatants of PBMC incubated with CVB4E2 or CVB3 and plasma from healthy subjects and, to a higher extent, from patients. The VP4 capsid proteins dissociated by heating at 56°C from CVB4E2 (VP4CVB4) and CVB3 (VP4CVB3) but not H antigen preincubated with plasma from healthy subjects or patients inhibited the plasma-dependent enhancement of CVB4E2- and CVB3-induced IFN-α synthesis. There was no cross-reaction between VP4CVB4 and VP4CVB3 in the inhibiting effect. IFN-α levels in culture supernatants showed dose-dependent correlation with anti-VP4 antibodies eluted from plasma specimens using VP4-coated plates. There were higher index values for anti-VP4 antibodies detected by enzyme-linked immunosorbent assay (ELISA) and higher proportions of positive detection in 40 patients than in 40 healthy subjects (80% versus 15% for anti-VP4CVB4). There was no relationship between the levels of anti-CVB neutralizing antibodies and the detection of anti-VP4 antibodies by ELISA. The CVB plasma-induced IFN-α levels obtained in PBMC cultures in the anti-VP4 antibody-positive groups were significantly higher than those obtained in the anti-VP4 antibody-negative groups regardless of the titers of anti-CVB neutralizing antibodies. These results show that VP4 is the target of antibodies involved in the plasma-dependent enhancement of CVB4E2- and CVB3-induced IFN-α synthesis by PBMC.

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