scholarly journals Prevalence of Linda Virus Neutralizing Antibodies in the Austrian Pig Population

Viruses ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 1001
Author(s):  
Alexandra Kiesler ◽  
Jakob Plankensteiner ◽  
Lukas Schwarz ◽  
Christiane Riedel ◽  
Kerstin Seitz ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Neutralizing Antibody ◽  
Serum Samples ◽  
Domestic Pig ◽  
Future Studies ◽  
Federal States ◽  
Porcine Serum ◽  
Genetic Level ◽  
Congenital Tremor ◽  
Reservoir Hosts

A novel pestivirus species, termed Lateral-shaking Inducing Neuro-Degenerative Agent virus (LindaV), was discovered in a piglet-producing farm in Austria in 2015 related to severe congenital tremor cases. Since the initial outbreak LindaV has not been found anywhere else. In this study, we determined the seroprevalence of LindaV infections in the domestic pig population of Austria. A fluorophore labeled infectious cDNA clone of LindaV (mCherry-LindaV) was generated and used in serum virus neutralization (SVN) assays for the detection of LindaV specific neutralizing antibodies in porcine serum samples. In total, 637 sera from sows and gilts from five federal states of Austria, collected between the years 2015 and 2020, were analyzed. We identified a single serum showing a high neutralizing antibody titer, that originated from a farm (Farm S2) in the proximity of the initially affected farm. The analysis of 57 additional sera from Farm S2 revealed a wider spread of LindaV in this pig herd. Furthermore, a second LindaV strain originating from this farm could be isolated in cell culture and was further characterized at the genetic level. Possible transmission routes and virus reservoir hosts of this emerging porcine virus need to be addressed in future studies.

scholarly journals A longitudinal study of SARS-CoV-2-infected patients reveals a high correlation between neutralizing antibodies and COVID-19 severity

2021 ◽  
Author(s):  
Vincent Legros ◽  
Solène Denolly ◽  
Manon Vogrig ◽  
Bertrand Boson ◽  
Eglantine Siret ◽  
...  
Keyword(s):  
Intensive Care ◽  
Neutralizing Antibodies ◽  
Vaccine Development ◽  
Surface Protein ◽  
Humoral Response ◽  
Neutralizing Antibody ◽  
Rapid Decline ◽  
Serum Samples ◽  
Immune Correlates ◽  
Human Coronaviruses

AbstractUnderstanding the immune responses elicited by SARS-CoV-2 infection is critical in terms of protection against reinfection and, thus, for public health policy and vaccine development for COVID-19. In this study, using either live SARS-CoV-2 particles or retroviruses pseudotyped with the SARS-CoV-2 S viral surface protein (Spike), we studied the neutralizing antibody (nAb) response in serum samples from a cohort of 140 SARS-CoV-2 qPCR-confirmed infections, including patients with mild symptoms and also more severe forms, including those that required intensive care. We show that nAb titers correlated strongly with disease severity and with anti-spike IgG levels. Indeed, patients from intensive care units exhibited high nAb titers; conversely, patients with milder disease symptoms had heterogeneous nAb titers, and asymptomatic or exclusive outpatient-care patients had no or low nAbs. We found that nAb activity in SARS-CoV-2-infected patients displayed a relatively rapid decline after recovery compared to individuals infected with other coronaviruses. Moreover, we found an absence of cross-neutralization between endemic coronaviruses and SARS-CoV-2, indicating that previous infection by human coronaviruses may not generate protective nAbs against SARS-CoV-2. Finally, we found that the D614G mutation in the spike protein, which has recently been identified as the current major variant in Europe, does not allow neutralization escape. Altogether, our results contribute to our understanding of the immune correlates of SARS-CoV-2-induced disease, and rapid evaluation of the role of the humoral response in the pathogenesis of SARS-CoV-2 is warranted.

scholarly journals Antibody titers measured by commercial assays are correlated with neutralizing antibody titers calibrated by international standards

2021 ◽  
Author(s):  
Yu-An Kung ◽  
Chung-Guei Huang ◽  
Sheng-Yu Huang ◽  
Kuan-Ting Liu ◽  
Peng-Nien Huang ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Vaccine Development ◽  
Geometric Mean ◽  
Neutralizing Antibody ◽  
Diagnostic Techniques ◽  
International Standards ◽  
World Health ◽  
Serum Samples ◽  
Antibody Titers ◽  
Health Organization

The World Health Organization (WHO) has highlighted the importance of an international standard (IS) for SARS-CoV-2 neutralizing antibody titer detection, with the aim of calibrating different diagnostic techniques. In this study, IS was applied to calibrate neutralizing antibody titers (IU/mL) and binding antibody titers (BAU/mL) in response to SARS-CoV-2 vaccines. Serum samples were collected from participants receiving the Moderna (n = 20) and Pfizer (n = 20) vaccines at three time points: pre-vaccination, after one dose, and after two doses. We obtained geometric mean titers of 1404.16 and 928.75 IU/mL for neutralizing antibodies after two doses of the Moderna and Pfizer vaccines, respectively. These values provide an important baseline for vaccine development and the implementation of non-inferiority trials. We also compared three commercially available kits from Roche, Abbott, and MeDiPro for the detection of COVID-19 antibodies based on binding affinity to S1 and/or RBD. Our results demonstrated that antibody titers measured by commercial assays are highly correlated with neutralizing antibody titers calibrated by IS.

Prevalence and Persistence of Maternal Dengue Neutralizing Antibodies in Infants From Central and Southern Thailand: A Retrospective Cohort Study

2019 ◽  
Vol 31 (4) ◽  
pp. 288-295 ◽  
Author(s):  
Adrienne Guignard ◽  
François Haguinet ◽  
Stéphanie Wéry ◽  
Phirangkul Kerdpanich
Keyword(s):  
Neutralizing Antibodies ◽  
Vaccine Development ◽  
Geometric Mean ◽  
Neutralizing Antibody ◽  
Maternal Antibodies ◽  
Childhood Immunization ◽  
Serum Samples ◽  
Denv Serotypes ◽  
Antibody Titers ◽  
Antibody Kinetics

Understanding maternal dengue virus (DENV) neutralizing antibody kinetics in infants remains timely to develop a safe and effective childhood immunization. This retrospective study evaluated the prevalence and persistence of maternal antibody titers against DENV serotypes 1 to 4 in 139 Thai infants at 2, 6, and 7 months of age, using serum samples collected in a vaccination trial ( http://clinicaltrials.gov ; NCT00197275). Neutralizing antibodies against all 4 DENV serotypes were detected in 87.8% and 22.9% of infants at 2 and 7 months, respectively. At 2 months, DENV-4 neutralizing antibody geometric mean titers were notably lower (80) compared with DENV-1 to DENV-3 (277-471). Our results corroborate previous findings that DENV-1 to DENV-4 maternal antibodies persist at 7 months despite titers decrease from 2 months onwards. As persisting maternal antibodies may inhibit immune responses in DENV-vaccinated infants, a comprehensive understanding of DENV antibody kinetics is required in the perspective of vaccine development for infants.

scholarly journals Prevalence of Neutralizing Antibodies against Different Rotavirus Serotypes in Children with Severe Rotavirus-Induced Diarrhea and Their Mothers

2004 ◽  
Vol 11 (1) ◽  
pp. 186-194 ◽  
Author(s):  
Pratibha G. Ray ◽  
Shobhana D. Kelkar
Keyword(s):  
Neutralizing Antibodies ◽  
Neutralizing Antibody ◽  
Serum Samples ◽  
Serotype A ◽  
Convalescent Phase ◽  
Human Rotavirus ◽  
Child Patients ◽  
Child Patient ◽  
Paired Serum ◽  
Rotavirus Diarrhea

ABSTRACT Neutralizing antibody (NAb) responses to different rotavirus serotypes were compared in 64 convalescent-phase serum samples from hospitalized rotavirus-positive children less than 2 years of age and their mothers. Compared to the child patients, the mothers showed significantly higher NAb positivity to animal rotavirus serotypes G3 simian (96.88%), G6 bovine (85.94%), and G10 bovine (25.0%) and to human rotavirus serotypes G8 (79.69%) and G3 (57.81%) (P < 0.01 for each) but not to human serotypes G1, G2, G4, and G9 (P > 0.05). The overall prevalence of NAb among the child patients was low for human rotavirus serotypes G1 (20.31%) and G3 (21.8%). The comparative NAb response in individual mother-child paired serum samples was analyzed against each rotavirus serotype. A substantial number of child patients showed higher NAb titers than their mothers to serotypes G1, G2, G4, and G9, indicating that these serotypes are the major serotypes causing rotavirus diarrhea among the children of Pune, India. In these cases, the mothers were either negative or had lower titers of NAbs than their children. Correlation was observed between the infecting serotype and child patient serum that showed a homologous NAb response at a higher level than that of the mother. It appears that when the level of NAb to a particular serotype is higher among child patients than among their mothers, that serotype is the infecting serotype, and that low titers of NAb among the mothers predispose the children to infection with that serotype, if the serotype is in circulation.

scholarly journals Persistence of Neutralizing Antibodies to SARS-CoV-2 in First Wave Infected Individuals at Ten Months Post-Infection: The UnIRSA Cohort Study

Viruses ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 2270
Author(s):  
Gloria Griffante ◽  
Shikha Chandel ◽  
Daniela Ferrante ◽  
Valeria Caneparo ◽  
Daniela Capello ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Vaccine Development ◽  
Natural Infection ◽  
Large Fraction ◽  
Geometric Mean ◽  
Neutralizing Antibody ◽  
Northern Italy ◽  
Serum Samples ◽  
Neutralization Titer ◽  
Igg Antibody

Longitudinal mapping of antibody-based SARS-CoV-2 immunity is critical for public health control of the pandemic and vaccine development. We performed a longitudinal analysis of the antibody-based immune response in a cohort of 100 COVID-19 individuals who were infected during the first wave of infection in northern Italy. The SARS-CoV-2 humoral response was tested using the COVID-SeroIndex, Kantaro Quantitative SARS-CoV-2 IgG Antibody RUO Kit (R&D Systems, Bio-Techne, Minneapolis, USA) and pseudotype-based neutralizing antibody assay. Using sequential serum samples collected from 100 COVID-19 recovered individuals from northern Italy—mostly with mild disease—at 2 and 10 months after their first positive PCR test, we show that 93% of them seroconverted at 2 months, with a geometric mean (GeoMean) half-maximal neutralization titer (NT50) of 387.9. Among the 35 unvaccinated subjects retested at 10 months, 7 resulted seronegative, with an 80% drop in seropositivity, while 28 showed decreased anti-receptor binding domain (RBD) and anti-spike (S) IgG titers, with a GeoMean NT50 neutralization titer dropping to 163.5. As an NT50 > 100 is known to confer protection from SARS-CoV-2 re-infection, our data show that the neutralizing activity elicited by the natural infection has lasted for at least 10 months in a large fraction of subjects.

scholarly journals Studies on the level of neutralizing antibodies produced by inactivated COVID-19 vaccines in the real world

2021 ◽  
Author(s):  
Haiying Zhang ◽  
Yuyuan Jia ◽  
Ying Ji ◽  
Xu Cong ◽  
Yan Liu ◽  
...  
Keyword(s):  
Real World ◽  
Linear Correlation ◽  
Neutralizing Antibodies ◽  
Neutralizing Antibody ◽  
Igg Antibodies ◽  
Serum Samples ◽  
The Real ◽  
Significant Difference ◽  
Positive Rate ◽  
High Linear Correlation

Background Although effective vaccines have been developed against COVID-19, the level of neutralizing antibodies (Nabs) induced after vaccination in the real world is still unknown. To evaluate the level and persistence of NAbs induced by two inactivated COVID-19 vaccines in China. Methods and findings Serum samples were collected from 1,335 people aged 18 and over who were vaccinated with COVID-19 inactivated vaccine in Peking University People's Hospital from January 19 to June 23, 2021, for detection of COVID-19 antibodies. The WHO standard of SARS-CoV-2 NAbs was detected. The coefficients of variation between the detection results and the true values of the NAbs detected by the WHO standard were all lower than the WHO international standard 3% after the dilution of the original and the dilution of the theoretical concentrations of 500 IU/mL, 250 IU/mL, 125 IU/mL, 72.5 IU/mL, 36.25 IU/mL and 18.125 IU/mL. On day 11-70, the positive rate of NAbs against COVID-19 was 82% to 100%; From day 71 to 332, the positive rate of NAbs decreased to 27%. The level of NAbs was significantly higher at 3-8 Weeks than at 0-3 Weeks. There was a high linear correlation between NAbs and IgG antibodies in 1335 vaccinated patients. NAbs levels were decreased in 31 of 38 people (81.6%) at two time points after the second dose of vaccine. There was no significant difference in age between the group with increased and decreased neutralizing antibody levels (x2 =-0.034, P>0.05). The positive rate of NAbs in the two-dose vaccine group (77.3%) was significantly higher than that in the one-dose group (18.1%), with statistical difference (x2=312.590, P<0.001). A total of 206 people who were 11-70 days after receiving the second dose were tested and divided into three groups: 18-40 years old, 41-60 years old and >60 years old. The positive rates of NAbs in three groups (18-40 years old, 41-60 years old and >60 years old) were 95.14%, 78.43% and 81.8%, respectively. The positive rate of NAbs was significantly higher in 18-40 years old than in 41-60 years old (x2=12.547, P <0.01). The titer of NAbs in 18-40 years old group was significantly higher than that in 41-60 years old group (t=-0.222, P <0.01). The positive rate of NAbs in male group (89.32%) was lower than in female (91.26%), but there was no significant difference (x2=0.222, P >0.05). Conclusions The positive rate of NAbs was the highest from 10 to 70 days after the second dose of vaccine, and the positive rate gradually decreased as time went by. There was a high linear correlation between COVID-19 NAbs and IgM/IgG antibodies in vaccinators, suggesting that in cases where NAbs cannot be detected, IgM/IgG antibodies can be detected instead. The level of NAbs produced after vaccination was affected by age, but not by gender. The highest levels of NAbs were produced between shots 21 to 56 days apart, suggesting that 21 to 56 days between shots is suitable for vaccination.

scholarly journals Calculating rabies virus neutralizing antibodies titres by flow cytometry

2002 ◽  
Vol 44 (3) ◽  
pp. 151-154 ◽  
Author(s):  
Juliano BORDIGNON ◽  
Fabiano COMIN ◽  
Sílvia Córdoba P. FERREIRA ◽  
Graciane M. M. CAPORALE ◽  
José Hermênio Cavalcante LIMA FILHO ◽  
...  
Keyword(s):  
Cell Culture ◽  
Flow Cytometry ◽  
Rabies Virus ◽  
Neutralizing Antibodies ◽  
Neutralizing Antibody ◽  
Standard Test ◽  
Serum Samples ◽  
Reference Serum ◽  
Infection Inhibition

The determination of the rabies neutralizing antibody (VNA) response after immunization against rabies is an acceptable index of the efficacy of a vaccine and a successful treatment. Several tests have been developed in attempt to improve the assessment of VNA, from mice inoculation to cell-culture fluorescence inhibition tests. All of them, however, present special difficulties in terms of reading or accuracy. The present study describes a neutralization test performed in cell-culture appraised by flow cytometry (FC). Serial dilutions of the serum samples were mixed in vitro with rabies virus before the addition of BHK-21 cells. After 24h-incubation, cells were released by trypsin treatment, fixed and permeabilized with a p-formaldehyde solution and stained with a rabies virus nucleocapsid protein-specific antibody conjugate. The percentage of virus infection inhibition caused by specific antibodies present in the serum were evaluated in a Beckton & Dickinson FACSCalibur® flow cytometer. A correlation curve between the IU/ml content and the percentage of infective inhibition was built with a reference serum and the VNA titers of serum samples were obtained by extrapolation. Titers obtained by FC and standard test showed an effective pairing results (p < 0.01), with a correlation coefficient (r) = 0.7. These results permit to envisage the FC as a suitable technique to evaluate VNA in sera from immunized animals and likely in human serum samples. Nevertheless, new studies comparing FC to gold-standard techniques are required for determining the FC values of Sensibility and Specificity .

scholarly journals Serological Evidence for the Circulation of Ebolaviruses in Pigs From Sierra Leone

2018 ◽  
Vol 218 (suppl_5) ◽  
pp. S305-S311 ◽  
Author(s):  
Kerstin Fischer ◽  
Juliet Jabaty ◽  
Roland Suluku ◽  
Thomas Strecker ◽  
Allison Groseth ◽  
...  
Keyword(s):  
Sierra Leone ◽  
Neutralizing Antibodies ◽  
Ebola Virus ◽  
The Philippines ◽  
Serum Samples ◽  
Susceptible Host ◽  
Transmission Cycle ◽  
Porcine Serum ◽  
Three Samples ◽  
Ebov Infection

Abstract Many human ebolavirus outbreaks have been linked to contact with wildlife including nonhuman primates and bats, which are assumed to serve as host species. However, it is largely unknown to what extent other animal species, particularly livestock, are involved in the transmission cycle or act as additional hosts for filoviruses. Pigs were identified as a susceptible host for Reston virus with subsequent transmission to humans reported in the Philippines. To date, there is no evidence of natural Ebola virus (EBOV) infection in pigs, although pigs were shown to be susceptible to EBOV infection under experimental settings. To investigate the potential role of pigs in the ecology of EBOV, we analyzed 400 porcine serum samples from Sierra Leone for the presence of ebolavirus-specific antibodies. Three samples reacted with ebolavirus nucleoproteins but had no neutralizing antibodies. Our results (1) suggest the circulation of ebolaviruses in swine in Sierra Leone that are antigenically related but not identical to EBOV and (2) could represent undiscovered ebolaviruses with unknown pathogenic and/or zoonotic potential.

scholarly journals SARS-CoV-2 antibodies remain detectable 12 months after infection and antibody magnitude is associated with age and COVID-19 severity

2021 ◽  
Author(s):  
Eric D. Laing ◽  
Nusrat J. Epsi ◽  
Stephanie A. Richard ◽  
Emily C. Samuels ◽  
Wei Wang ◽  
...  
Keyword(s):  
Symptom Onset ◽  
Neutralizing Antibodies ◽  
Natural Infection ◽  
Geometric Mean ◽  
Neutralizing Antibody ◽  
Antibody Responses ◽  
Serum Samples ◽  
Military Hospitals ◽  
Igg Binding ◽  
One Year

ABSTRACTImportanceThe persistence of SARS-CoV-2 antibodies may be a predictive correlate of protection for both natural infections and vaccinations. Identifying predictors of robust antibody responses is important to evaluate the risk of re-infection / vaccine failure and may be translatable to vaccine effectiveness.ObjectiveTo 1) determine the durability of anti-SARS-CoV-2 IgG and neutralizing antibodies in subjects who experienced mild and moderate to severe COVID-19, and 2) to evaluate the correlation of age and IgG responses to both endemic human seasonal coronaviruses (HCoVs) and SARS-CoV-2 according to infection outcome.DesignLongitudinal serum samples were collected from PCR-confirmed SARS-CoV-2 positive participants (U.S. active duty service members, dependents and military retirees, including a range of ages and demographics) who sought medical treatment at seven U.S. military hospitals from March 2020 to March 2021 and enrolled in a prospective observational cohort study.ResultsWe observed SARS-CoV-2 seropositivity in 100% of inpatients followed for six months (58/58) to one year (8/8), while we observed seroreversion in 5% (9/192) of outpatients six to ten months after symptom onset, and 18% (2/11) of outpatients followed for one year. Both outpatient and inpatient anti-SARS-CoV-2 binding-IgG responses had a half-life (T1/2) of >1000 days post-symptom onset. The magnitude of neutralizing antibodies (geometric mean titer, inpatients: 378 [246-580, 95% CI] versus outpatients: 83 [59-116, 95% CI]) and durability (inpatients: 65 [43-98, 95% CI] versus outpatients: 33 [26-40, 95% CI]) were associated with COVID-19 severity. Older age was a positive correlate with both higher IgG binding and neutralizing antibody levels when controlling for COVID-19 hospitalization status. We found no significant relationships between HCoV antibody responses and COVID-19 clinical outcomes, or the development of SARS-CoV-2 neutralizing antibodies.Conclusions and RelevanceThis study demonstrates that humoral responses to SARS-CoV-2 infection are robust on longer time-scales, including those arising from milder infections.However, the magnitude and durability of the antibody response after natural infection was lower and more variable in younger participants who did not require hospitalization for COVID-19. These findings support vaccination against SARS-CoV-2 in all suitable populations including those individuals that have recovered from natural infection.

scholarly journals Neutralization of Dengue Virus Serotypes by Sera from Dengue-Infected Individuals Is Preferentially Directed to Heterologous Serotypes and Not against the Autologous Serotype Present in Acute Infection

Viruses ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1957
Author(s):  
Heidi Auerswald ◽  
Simone Kann ◽  
Leonard Klepsch ◽  
Janne Hülsemann ◽  
Ines Rudnik ◽  
...  
Keyword(s):  
Serum Sample ◽  
Neutralizing Antibodies ◽  
Secondary Infection ◽  
Acute Infection ◽  
Neutralizing Antibody ◽  
Serum Samples ◽  
Denv Serotypes ◽  
Multiple Virus ◽  
Dengue Virus Serotypes ◽  
Paired Serum

Sequential infections of humans by the four different dengue serotypes (DENV-1–4) lead to neutralizing antibodies with group, cross, and type specificity. Virus neutralization of serotypes showed monotypic but mostly multitypic neutralization profiles due to multiple virus exposures. We have studied neutralization to heterologous, reference DENV serotypes using paired sera collected between days 6 and 37 after onset of fever. The DENV-primed neutralization profile of the first serum sample, which was monitored by a foci reduction neutralization test (FRNT), was boosted but the neutralization profile stayed unchanged in the second serum sample. In 45 of 47 paired serum samples, the predominant neutralization was directed against DENV serotypes distinct from the infecting serotype. Homologous neutralization studies using sera and viruses from the same area, 33 secondary sera from DENV-1 infected Cambodian patients and eight virus isolates from Cambodia, showed that the FRNT assay accurately predicted the lack of a predominant antibody response against the infecting DENV-1 serotype in contrast to FRNT results using the WHO set of DENV viruses. This report provides evidence that DENV-primed multitypic neutralizing antibody profiles were mainly boosted and stayed unchanged after secondary infection and that DENV neutralization was predominantly directed to heterologous DENV but not against the infecting homologous serotype.

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