scholarly journals Use of a Surrogate Chimeric Virus To Detect West Nile Virus-Neutralizing Antibodies in Avian and Equine Sera

2008 ◽  
Vol 16 (1) ◽  
pp. 134-135 ◽  
Author(s):  
Nicholas Komar ◽  
Stanley Langevin ◽  
Thomas P. Monath
Keyword(s):  
West Nile Virus ◽  
Neutralizing Antibodies ◽  
Yellow Fever Virus ◽  
Neutralizing Antibody ◽  
Serum Samples ◽  
West Nile ◽  
Virus West Nile ◽  
Antibody Titers ◽  
Level 2 ◽  
Biosafety Level

ABSTRACT A chimeric yellow fever virus/West Nile virus (WNV) was compared to WNV alone as a biosafety level 2 reagent in the plaque reduction neutralization test for determining WNV infection histories. Concordance was 96.3% among 188 avian and equine serum samples. Neutralizing antibody titers were frequently more than twofold lower with the chimera.

scholarly journals Serological evidence of West Nile virus infection in the horse population of northern Serbia

2014 ◽  
Vol 8 (07) ◽  
pp. 914-918 ◽  
Author(s):  
Strahinja Medić ◽  
Rene Van den Hoven ◽  
Tamaš Petrović ◽  
Diana Lupulović ◽  
Norbert Nowotny
Keyword(s):  
West Nile Virus ◽  
West Nile Virus Infection ◽  
Neutralizing Antibody ◽  
Manuscript Preparation ◽  
Serum Samples ◽  
West Nile ◽  
Horse Population ◽  
Antibody Titers ◽  
Antibody Elisa ◽  
Lineage 2

Introduction: This study was conducted to evaluate the seroprevalence of West Nile virus (WNV) in the horse population of northern Serbia. Furthermore, it aimed to provide insight and an updated overview on the circulation of this re-emerging pathogen in this part of southeastern Europe. At the time of manuscript preparation, no clinical cases of WNV infection in horses were reported in this area. Methodology: Between 2007 and 2011, a total of 252 equine serum samples were collected from seven different locations in northern Serbia. The presence of WNV-reactive IgG antibodies was examined by using commercial and in-house ELISAs. Selected ELISA-positive samples were re-tested by a WNV lineage 2 plaque reduction neutralization test 90% (PRNT-90). Results: In 28.6% of the 252 tested equine serum samples antibodies against WNV were detected. The results obtained with the in-house ELISA corresponded to the outcome of the commercial kit in 90% of the samples. All selected WNV antibody ELISA-positive samples were confirmed by PRNT-90 with neutralizing antibody titers of 1:23 to > 1:512. Conclusion: This study confirms the circulation of WNV in northern Serbia. No striking regional differences in seroprevalences were identified suggesting WNV circulation also in other parts of Serbia. Distances between wetlands or forests and stud farms do not appear to have an influence on WNV seroprevalence.

scholarly journals Durability of Response to a Third BNT162b2 Vaccine in Adults ≥60 Years

2021 ◽  
Author(s):  
Noa Eliakim Raz ◽  
Amos Stemmer ◽  
Yaara Leibovici-Weissman ◽  
Asaf Ness ◽  
Muhammad Awwad ◽  
...  
Keyword(s):  
Adverse Events ◽  
Neutralizing Antibodies ◽  
Multivariable Analysis ◽  
Vaccine Dose ◽  
Neutralizing Antibody ◽  
Clinical Frailty Scale ◽  
Younger Adults ◽  
The Third ◽  
Antibody Titers ◽  
Level 2

BACKGROUND Age and frailty are strong predictors of COVID-19 mortality. After the second BNT162b2 dose, immunity wanes faster in older (≥65 years) versus younger adults. The durability of response after the third vaccine is unclear. METHODS This prospective cohort study included healthcare workers/family members ≥60 years who received a third BNT162b2 dose. Blood samples were drawn immediately before (T0), 10-19 (T1), and 74-103 (T2) days after the third dose. Antispike IgG titers were determined using a commercial assay, seropositivity was defined as ≥50 AU/mL. Neutralizing antibody titers were determined at T2. Adverse events, COVID-19 infections, and clinical frailty scale (CFS) levels were documented. RESULTS The analysis included 97 participants (median age, 70 years [IQR, 66-74], 61% women, 58% CFS level 2). IgG titers, which increased significantly from T0 to T1 (medians, 440 AU/mL [IQR, 294-923] and 25,429 [14,203-36,114] AU/mL, respectively; P<0.001), decreased significantly by T2, but all remained seropositive (median, 8,306 AU/mL [IQR, 4595-14,701], P<0.001 vs T1). In a multivariable analysis, only time from the first vaccine was significantly associated with lower IgG levels at T2 (P=0.004). At T2, 60 patients were evaluated for neutralizing antibodies; all were seropositive (median, 1,294 antibody titer [IQR, 848-2,072]). Neutralizing antibody and antispike IgG levels were correlated (R=0.6, P<0.001). No major adverse events or COVID-19 infections were reported. CONCLUSIONS Antispike IgG and neutralizing antibodies levels remain adequate 3 months after the third BNT162b2 vaccine in healthy adults ≥60 years, although the decline in IgG is concerning. A third vaccine dose in this population should be top priority.

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 Induction of Epitope-Specific Neutralizing Antibodies against West Nile Virus

2007 ◽  
Vol 81 (21) ◽  
pp. 11828-11839 ◽  
Author(s):  
Theodore Oliphant ◽  
Grant E. Nybakken ◽  
S. Kyle Austin ◽  
Qing Xu ◽  
Jonathan Bramson ◽  
...  
Keyword(s):  
West Nile Virus ◽  
Human Serum ◽  
Neutralizing Antibodies ◽  
Immunoglobulin M ◽  
Late Time ◽  
Loss Of Function ◽  
Serum Samples ◽  
West Nile ◽  
E Protein ◽  
Low Levels

ABSTRACT Previous studies have established that an epitope on the lateral ridge of domain III (DIII-lr) of West Nile virus (WNV) envelope (E) protein is recognized by strongly neutralizing type-specific antibodies. In contrast, an epitope against the fusion loop in domain II (DII-fl) is recognized by flavivirus cross-reactive antibodies with less neutralizing potential. Using gain- and loss-of-function E proteins and wild-type and variant WNV reporter virus particles, we evaluated the expression pattern and activity of antibodies against the DIII-lr and DII-fl epitopes in mouse and human serum after WNV infection. In mice, immunoglobulin M (IgM) antibodies to the DIII-lr epitope were detected at low levels at day 6 after infection. However, compared to IgG responses against other epitopes in DI and DII, which were readily detected at day 8, the development of IgG against DIII-lr epitope was delayed and did not appear consistently until day 15. This late time point is notable since almost all death after WNV infection in mice occurs by day 12. Nonetheless, at later time points, DIII-lr antibodies accumulated and comprised a significant fraction of the DIII-specific IgG response. In sera from infected humans, DIII-lr antibodies were detected at low levels and did not correlate with clinical outcome. In contrast, antibodies to the DII-fl were detected in all human serum samples and encompassed a significant percentage of the anti-E protein response. Our experiments suggest that the highly neutralizing DIII-lr IgG antibodies have little significant role in primary infection and that the antibody response of humans may be skewed toward the induction of cross-reactive, less-neutralizing antibodies.

scholarly journals Exposure of Horses in Israel to West Nile Virus and Usutu Virus

Viruses ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 1099
Author(s):  
Gili Schvartz ◽  
Sharon Tirosh-Levy ◽  
Oran Erster ◽  
Roni Shenhar ◽  
Hadas Levy ◽  
...  
Keyword(s):  
West Nile Virus ◽  
Middle East ◽  
Neutralizing Antibodies ◽  
Mosquito Vectors ◽  
Serum Samples ◽  
West Nile ◽  
East Europe ◽  
Zoonotic Pathogen ◽  
Usutu Virus ◽  
Neuroinvasive Disease

West Nile virus (WNV) and Usutu virus (USUV) are arboviruses transmitted by mosquito vectors. Whereas WNV is endemic in Israel, the Middle East, Europe, and in the Americas, data regarding the prevalence of USUV in the Middle East is limited. While both viruses share similar reservoirs and vectors, exposure of horses in the area to USUV have never been assessed. The aim of this study was to estimate the seroprevalence and co-exposure of WNV and USUV in horses in Israel. A total of 327 serum samples from healthy unvaccinated horses in Israel collected in 2018 were tested for neutralizing antibodies against WNV and USUV. Seroprevalence for neutralizing antibodies against WNV and USUV was 84.1% and 10.8%, respectively. Management and age were significantly associated with WNV and USUV seropositivity. This is the first report describing exposure of horses in Israel to USUV, which indicates that this zoonotic pathogen should be included in the differential diagnosis list of neuroinvasive disease in this country.

West Nile virus neutralizing antibody prevalence in donkeys from northern Nigeria

2020 ◽  
Author(s):  
Idoko Sunday Idoko ◽  
Gili Schvartz ◽  
Sharon Tirosh-Levy ◽  
Oran Erster ◽  
Jibril Yakubu Jibril ◽  
...  
Keyword(s):  
West Nile Virus ◽  
Neutralizing Antibodies ◽  
Healthy Adult ◽  
Neutralization Test ◽  
Neutralizing Antibody ◽  
Virus Neutralization Test ◽  
Northern Nigeria ◽  
Antibody Prevalence ◽  
West Nile ◽  
Zoonotic Pathogen

Abstract Background This study aimed to evaluate the prevalence of anti-West Nile virus (WNV) neutralizing antibodies in donkeys from two areas in northern Nigeria. Methods Serology was determined by a virus neutralization test in samples collected from 205 healthy adult donkeys. Results Fifty-seven donkeys (27.8%) tested seropositive for WNV. Donkeys from Zaria were 2.6 times more likely to have been exposed to WNV (p&lt;0.001). Conclusion The results of this study demonstrate that this zoonotic pathogen is prevalent in these areas and that measures should be implemented to reduce the risk for both humans and equids.

scholarly journals Development and Validation of an Assay To Detect Porcine Reproductive and Respiratory Syndrome Virus-Specific Neutralizing Antibody Titers in Pig Oral Fluid Samples

2013 ◽  
Vol 20 (8) ◽  
pp. 1305-1313 ◽  
Author(s):  
Kang Ouyang ◽  
Basavaraj Binjawadagi ◽  
Apisit Kittawornrat ◽  
Chris Olsen ◽  
Jagadish Hiremath ◽  
...  
Keyword(s):  
Disease Surveillance ◽  
Neutralizing Antibodies ◽  
Oral Fluid ◽  
Low Cost ◽  
Herd Immunity ◽  
Neutralizing Antibody ◽  
Respiratory Syndrome Virus ◽  
Serum Samples ◽  
Antibody Titers ◽  
Breeding Farms

ABSTRACTPorcine reproductive and respiratory syndrome virus (PRRSV)-specific neutralizing antibodies (NA) are important for clearing the virus. Pen-based pig oral fluid samples for disease surveillance are gaining in importance due to the ease of collection and low cost. The aim of this study was to develop a PRRSV-specific NA assay to determine NA titers in pig oral fluid samples. At first, we standardized the PRRSV NA assay using pen-based pig oral fluid samples collected over a period of 3 months from a herd of swine that received a PRRSV modified live vaccine (PRRS-MLV), and we also used oral fluid and serum samples collected from individual boars that were vaccinated with PRRS-MLV or infected with a virulent PRRSV strain. Our results suggest that a PRRSV NA titer of >8 in oral fluid samples is virus specific and can be detected beginning at 28 days after vaccination or infection. To validate the assay, we used 104 pen-based pig oral fluid and five representative serum samples from each pen of unknown history, as well as 100 serum samples from repeatedly vaccinated sows and oral fluid samples of their respective litters belonging to four different swine-breeding farms. Our results demonstrated that PRRSV NA titers in oral fluid samples are correlated with serum sample titers, and maternally derived PRRSV-specific NA titers could be detected in litters at the time of weaning. In conclusion, we have standardized and validated the pig oral fluid-based PRRSV NA assay, which has 94.3% specificity and 90.5% repeatability. The assay can be used to monitor herd immunity against PRRSV in vaccinated and infected herds of swine.

scholarly journals Antibodies against rabies virus in dogs with and without history of vaccination in Santa Maria - RS - Brazil

2017 ◽  
Vol 47 (11) ◽  
Author(s):  
Karina Gonzalez Fernandes ◽  
Mathias Martins ◽  
Bruna Portolan Amaral ◽  
Juliana Felipetto Cargnelutti ◽  
Rudi Weiblen ◽  
...  
Keyword(s):  
Rabies Virus ◽  
Neutralizing Antibodies ◽  
Neutralizing Antibody ◽  
World Health ◽  
Serum Samples ◽  
Antibody Titers ◽  
Group A ◽  
Group B ◽  
Santa Maria ◽  
Rabies Vaccination

ABSTRACT: The present study investigated the frequency and magnitude of neutralizing antibodies to rabies virus (RABV) in dogs with and without historic of vaccination in Santa Maria/RS. Group A included serum samples from 440 dogs with recent historic of vaccination against rabies, obtained during the 2015 rabies vaccination campaign. Group B included 300 serum samples from dogs submitted to the Veterinary Hospital of the Universidade Federal de Santa Maria in 2015, whose historic of rabies vaccination was unknown. Serum samples were submitted to the rapid fluorescent focus inhibition test (RFFIT) to detect neutralizing antibodies against RABV. In group A, 70.6% (310/440) of the samples had neutralizing antibody titers ≥0.5 international units per milliliter (IU mL-1), considered an indicative of protection against rabies by the World Health Organization. However, approximately 30% of the dogs did not contain antibodies in adequate levels. In group B, 42.3% (127/300) of the samples contained neutralizing antibody titers ≥0.5IU mL-1 and 57.7% (173/300) were negative or contained titers below of the value considered immunized. These results demonstrate that an important proportion of vaccinated dogs (~30%) did not develop adequate antibody levels, mainly those receiving a single vaccine dose. Serologic testing of animals with unknown historic of vaccination revealed relatively low vaccine coverage in the general dog population. Thus, reformulation of immunization strategies - especially the recommendation of a boost vaccination 30 days after the primary dose - and extension of vaccination campaigns are necessary to reach adequate levels and coverage of immunity against RABV in the canine population.

scholarly journals Preliminary Study on the Prevalence of West Nile Virus Antibody among Horses, Donkeys and Camels in Borno State, Nigeria

2014 ◽  
Vol 3 (2) ◽  
pp. 39 ◽  
Author(s):  
Saka Saheed Baba ◽  
Obinna Damian NNnadi ◽  
Kenas Dunama Hamman ◽  
Awal Saidu ◽  
Abduldahiru El Yuguda ◽  
...  
Keyword(s):  
West Nile Virus ◽  
Virus Infection ◽  
Host Range ◽  
Neutralizing Antibody ◽  
Virus Antibody ◽  
Serum Samples ◽  
West Nile ◽  
Significant Difference ◽  
Preliminary Study

<p>In spite of several serological evidences for the presence of West Nile (WN) virus in Nigeria, the host range of the virus is not fully understood. In this study, the prevalence of the WN virus antibody was determined among horse, donkey and camel populations in Borno state, Nigeria. Two hundred and fifty serum samples comprising of 96 sera from each of horses and camels and 58 from donkeys were tested for presence of WN virus neutralizing antibody. An overall prevalence of WN virus neutralizing antibody of 13.2% was noted in the population of animals tested.  Significant difference (P≤0.05) in prevalence was observed between the animals tested. Highest prevalence (17.7%) was noted in camels followed by horses (11.5%) and donkeys (8.6%). The results of this study confirmed the prevalence of WV virus antibody in camels in Nigeria and represented the first serosurvey for WN virus activities among horses and donkeys in this part of the country. There is considerable activity of the virus in the study area and provided evidence for the potential roles this group of animals could play in the epidemiology of WN virus infection in Nigeria.</p>

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