scholarly journals Humoral immune response after COVID-19 infection or BNT162b2 vaccine among older adults: evolution over time and protective thresholds.

2021 ◽  
Author(s):  
Maxence Meyer ◽  
Florentin Constancias ◽  
Claudia Worth ◽  
Anita Meyer ◽  
Marion Muller ◽  
...  
Keyword(s):  
Serological Test ◽  
Natural Infection ◽  
Clinical Results ◽  
Current Data ◽  
Vaccine Group ◽  
Test Results ◽  
Infection Group ◽  
Vaccine Protection ◽  
Humoral Immune ◽  
Over Time

INTRODUCTION The objectives of this study were to assess the dynamics of the SARS-CoV-2 anti-RBD IgG response over time among older people after COVID-19 infection or vaccination and its comparison with speculative levels of protection assumed by current data. METHODS From November 2020 to October 2021, we included geriatric patients with serological test results for COVID-19. We considered antibody titre thresholds thought to be high enough to protect against SARS-CoV-2 infection: 141 BAU/ml for protection/vaccine efficacy > 89.3%. Three cohorts are presented. A vaccine group (n=34) that received two BNT162b2/Comirnaty injections 21 days apart, a group of natural COVID-19 infection (n=32) and a third group who contracted COVID-19 less than 15 days after the first BNT162b2/Comirnaty injection (n=17). RESULTS 83 patients were included, the median age was 87 (81-91) years. In the vaccine group at 1 month since the first vaccination, the median BAU/ml with IQR was 620 (217-1874) with 87% of patients above the threshold of 141 BAU/ml. Seven months after the first vaccination the BAU/ml was 30 (19-58) with 9.5% of patients above the threshold of 141 BAU/ml. In the natural COVID-19 infection group, at 1 month since the date of first symptom onset, the median BAU/ml was 798 (325-1320) with 86.7% of patients above the threshold of 141 BAU/ml and fell to 88 (37-385) with 42.9% of patients above the threshold of 141 BAU/ml at 2 months. The natural infection group was vaccinated three months after the infection. Five months after the end of the vaccination cycle the BAU/ml was 2048 (471-4386) with 83.3% of patients above the threshold of 141 BAU/ml. DISCUSSION On the humoral level, this supports the clinical results describing the decrease in vaccine protection over time.

scholarly journals Maternally Derived Antibody Levels Influence on Vaccine Protection against PCV2d Challenge

Animals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 2231
Author(s):  
István Kiss ◽  
Krisztina Szigeti ◽  
Zalán G. Homonnay ◽  
Vivien Tamás ◽  
Han Smits ◽  
...  
Keyword(s):  
Immune Response ◽  
Humoral Immune Response ◽  
Subunit Vaccine ◽  
Porcine Circovirus Type ◽  
Porcine Circovirus ◽  
Vaccine Protection ◽  
Humoral Immune ◽  
Negative Effect ◽  
Antibody Levels

Piglets from a porcine circovirus type 2 (PCV2) stable farm of low and high levels of maternally derived antibodies (MDA) against PCV2 were vaccinated either with a whole virus type or a PCV2 ORF2 antigen-based commercial subunit vaccine at three weeks of age. Two non-vaccinated groups served as low and high MDA positive controls. At four weeks post vaccination, all piglets were challenged with a PCV2d-2 type virus strain and were checked for parameters related to vaccine protection over a four-week observation period. MDA levels evidently impacted the outcome of the PCV2d-2 challenge in non-vaccinated animals, while it did not have a significant effect on vaccine-induced protection levels. The humoral immune response developed faster in the whole virus vaccinates than in the subunit vaccinated pigs in the low MDA groups. Further, high MDA levels elicited a stronger negative effect on the vaccine-induced humoral immune response for the subunit vaccine than for the whole virus vaccine. The group-based oral fluid samples and the group mean viraemia and faecal shedding data correlated well, enabling this simple, and animal welfare-friendly sampling method for the evaluation of the PCV2 viral load status of these nursery piglets.

scholarly journals Evolution of immune responses to SARS-CoV-2 in mild-moderate COVID-19

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Adam K. Wheatley ◽  
Jennifer A. Juno ◽  
Jing J. Wang ◽  
Kevin J. Selva ◽  
Arnold Reynaldi ◽  
...  
Keyword(s):  
T Cell ◽  
B Cell ◽  
Vaccine Development ◽  
Natural Infection ◽  
Population Level ◽  
Cell Dynamics ◽  
Follicular Helper ◽  
Cell Immunity ◽  
Specific Igg ◽  
Over Time

AbstractThe durability of infection-induced SARS-CoV-2 immunity has major implications for reinfection and vaccine development. Here, we show a comprehensive profile of antibody, B cell and T cell dynamics over time in a cohort of patients who have recovered from mild-moderate COVID-19. Binding and neutralising antibody responses, together with individual serum clonotypes, decay over the first 4 months post-infection. A similar decline in Spike-specific CD4+ and circulating T follicular helper frequencies occurs. By contrast, S-specific IgG+ memory B cells consistently accumulate over time, eventually comprising a substantial fraction of circulating the memory B cell pool. Modelling of the concomitant immune kinetics predicts maintenance of serological neutralising activity above a titre of 1:40 in 50% of convalescent participants to 74 days, although there is probably additive protection from B cell and T cell immunity. This study indicates that SARS-CoV-2 immunity after infection might be transiently protective at a population level. Therefore, SARS-CoV-2 vaccines might require greater immunogenicity and durability than natural infection to drive long-term protection.

scholarly journals Interpretation of serological test results for Simian herpes B virus

2001 ◽  
Vol 35 (4) ◽  
pp. 315-320 ◽  
Author(s):  
S. E. Wolfensohn ◽  
R. Gopal
Keyword(s):  
Macaca Mulatta ◽  
Macaca Fascicularis ◽  
Screening Programme ◽  
Serological Test ◽  
Test Results ◽  
Specific Pathogen Free ◽  
B Virus ◽  
Specific Pathogen ◽  
Herpes B Virus ◽  
Experimental Group

In 1992 an annual Simian herpes B virus (BV) screening programme for an experimental group of macaque monkeys ( Macaca mulatta and Macaca fascicularis) was initiated with the aim of establishing a specific pathogen free (SPF) colony. In June 1999 one animal was found to be unexpectedly BV positive (non-negative). The investigation of this result highlights some of the issues and difficulties that may be encountered in such a programme.

scholarly journals Evaluation of six commercial SARS-CoV-2 serology assays detecting different antibodies for clinical testing and serosurveillance

2021 ◽  
Author(s):  
Suellen Nicholson ◽  
Theo Karapanagiotidis ◽  
Arseniy Khvorov ◽  
Celia Douros ◽  
Francesca Mordant ◽  
...  
Keyword(s):  
Cell Culture ◽  
Neutralization Test ◽  
Serological Test ◽  
Neutralizing Antibody ◽  
Neutralization Assay ◽  
Virus Neutralization Test ◽  
Virus Neutralization ◽  
Binding Assays ◽  
Humoral Immune ◽  
A Cell

Abstract Background Serological testing for SARS-CoV-2 complements nucleic acid tests for patient diagnosis and enables monitoring of population susceptibility to inform the COVID-19 pandemic response. It is important to understand the reliability of assays with different antigen or antibody targets to detect humoral immunity after SARS-CoV-2 infection and to understand how antibody (Ab) binding assays compare to those detecting neutralizing antibody (nAb), particularly as we move into the era of vaccines. Methods We evaluated the performance of six commercially available Enzyme-linked Immunosorbent Assays (ELISAs), including a surrogate virus neutralization test (sVNT), for detection of SARS-CoV-2 immunoglobulins (IgA, IgM, IgG), total or nAb. A result subset was compared to a cell culture-based microneutralisation (MN) assay. We tested sera from patients with prior RT-PCR confirmed SARS-CoV-2 infection, pre-pandemic sera and potential cross-reactive sera from patients with other non-COVID-19 acute infections. Results For sera collected > 14 days post-symptom onset, the assay achieving the highest sensitivity was the Wantai total Ab at 100% (95% confidence interval: 94.6-100) followed by 93.1% for Euroimmun NCP-IgG, 93.1% for GenScript sVNT, 90.3% for Euroimmun S1-IgG, 88.9% for Euroimmun S1-IgA and 83.3% for Wantai IgM. Specificity for the best performing assay was 99.5% for the Wantai total Ab and for the lowest performing assay was 97.1% for sVNT (as per IFU). The Wantai Total Ab had the best agreement with MN at 98% followed by Euroimmun S1-IgA, Euro NCP-IgG and sVNT (as per IFU) with (97%, 97% and 95% respectively) and Wantai IgM having the poorest agreement at 93%. Conclusion Performance characteristics of the SARS-CoV-2 serology assays detecting different antibody types are consistent with those found in previously published reports. Evaluation of the surrogate virus neutralization test in comparison to the Ab binding assays and a cell culture-based neutralization assay showed good result correlation between all assays. However correlation between the cell-based neutralization test and some assays detecting Ab’s not specifically involved in neutralization was higher than with the sVNT. This study demonstrates the reliability of different assays to detect the humoral immune response following SARS-CoV-2 infection, which can be used to optimise serological test algorithms for assessing antibody responses post SARS-CoV-2 infection or vaccination.

Constrained Shape Scaling of Trimmed NURBS Surfaces

1999 ◽  
Author(s):  
Pifu Zhang ◽  
Caiming Zhang ◽  
Fuhua (Frank) Cheng
Keyword(s):  
Data Exchange ◽  
Surface Deformation ◽  
Current Data ◽  
Free Form ◽  
Test Results ◽  
Nurbs Surface ◽  
Curvature Distribution ◽  
The Given ◽  
Boundary Curves

Abstract A method to scale and deform a trimmed NURBS surface while holding the shape and size of specific features (trimming curves) unchanged is presented. The new surface is formed by scaling the given surface according to the scaling requirement first; and then attaching the (original) features to the scaled NURBS surface at appropriate locations. The attaching process requires several geometric operations and constrained free-form surface deformation. The resulting surface has the same features as the original surface and same boundary curves as the scaled surface while reflecting the shape and curvature distribution of the scaled surface. This is achieved by minimizing a shape-preserving objective function which covers all the factors in the deformation process such as bending, stretching and spring effects. The resulting surface maintains a NURBS representation and, hence, is compatible with most of the current data-exchange standards. Test results on several car parts with trimming curves are included. The, quality of the resulting surfaces is examined using the highlight line model.

Test of Solidification Characteristics of Grouting and the Effect on Strata Deformation in Shield Tunnelling

2012 ◽  
Vol 568 ◽  
pp. 80-84
Author(s):  
Xiao Chun Zhong ◽  
Wei Ke Qin ◽  
Hai Wang
Keyword(s):  
Numerical Model ◽  
Rigid Body ◽  
Active Control ◽  
Calculation Method ◽  
Civil Engineering ◽  
Test Results ◽  
Shield Tunneling ◽  
Shield Tunnelling ◽  
Strata Deformation ◽  
Over Time

Back-fill Grouting is a key procedure for the active control of strata settlement during shield tunnelling in civil engineering. The paper studies the stress - strain characteristics of grouting and the state of grout, which changes from liquid to solid over time and is simulated by variable rigid body. The model of flowing state are divided in four phases from liquid-plastic to rigid state. The paper establish a numerical model of shield tunnelling in civil engineering with the consideration of characteristics of grout deformation, and has analyzed law of strata settlement. The test results show that the calculation method can well accord with the four stages of strata deformation, and can more accurately reflect the process of strata deformation caused by shield tunneling.

scholarly journals An Attenuated Cytomegalovirus Vaccine with a Deletion of a Viral Chemokine Gene Is Protective against Congenital CMV Transmission in a Guinea Pig Model

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Michael P. Leviton ◽  
Juan C. Lacayo ◽  
K. Yeon Choi ◽  
Nelmary Hernandez-Alvarado ◽  
Andrew Wey ◽  
...  
Keyword(s):  
Guinea Pig ◽  
Guinea Pigs ◽  
Natural Infection ◽  
Group Versus ◽  
Vaccine Group ◽  
Control Group ◽  
Live Virus ◽  
Chemokine Gene ◽  
Immunization Group ◽  
Viral Vaccine

Development of a vaccine against congenital cytomegalovirus (CMV) infection is a public health priority, but CMVs encode immune evasion genes that complicate live virus vaccine design. To resolve this problem, this study employed guanosyl phosphoribosyl transferase (gpt) mutagenesis to generate a recombinant guinea pig CMV (GPCMV) with a knockout of a viral chemokine gene, GPCMV MIP (gp1). MIP deletion virus replicated with wild-type kinetics in cell culture but was attenuated in nonpregnant guinea pigs, demonstrating reduced viremia and reduced inflammation and histopathology (compared to a control virus with an intact GPCMV MIP gene) following footpad inoculation. In spite of attenuation, the vaccine was immunogenic, eliciting antibody responses comparable to those observed in natural infection. To assess its protective potential as a vaccine, either recombinant virus or placebo was used to immunize seronegative female guinea pigs. Dams were challenged in the early 3rd trimester with salivary gland-adapted GPCMV. Immunization protected against DNAemia (1/15 in vaccine group versus 12/13 in the control group,P<0.01). Mean birth weights were significantly higher in pups born to vaccinated dams compared to controls (98.7 g versus 71.2 g,P<0.01). Vaccination reduced pup mortality, from 35/50 (70%) in controls to 8/52 (15%) in the immunization group. Congenital GPCMV infection was also reduced, from 35/50 (70%) in controls to 9/52 (17%) in the vaccine group (P<0.0001). We conclude that deletion of an immune modulation gene can attenuate the pathogenicity of GPCMV while resulting in a viral vaccine that retains immunogenicity and demonstrates efficacy against congenital infection and disease.

scholarly journals Use of free microvascular flaps in the management of the head and neck defects

2006 ◽  
Vol 63 (8) ◽  
pp. 713-720 ◽  
Author(s):  
Zivorad Nikolic ◽  
Jelena Jeremic ◽  
Radoje Milosavljevic
Keyword(s):  
Head And Neck ◽  
Gold Standard ◽  
Clinical Observation ◽  
Clinical Results ◽  
Test Results ◽  
Flap Necrosis ◽  
Free Flap Reconstruction ◽  
Microsurgical Reconstruction ◽  
Flap Viability ◽  
Patient Series

Background/aim: In the field of contemporary head and neck reconstructive surgery, free vascularized tissue transfer is becoming a gold standard. The aim of this study was to review our clinical results and experience, with use of free microvascular flaps and compare them with the recently published patient series. Methods. During the period from 2001 to 2005, 37 patients underwent microsurgical reconstruction after the tumor ablation in the region of head and neck. Flap viability was monitored intraoperatively with the Ackland test and postoperatively by the clinical observation and mini-Doppler test. Results. The overall success rate was 83.8%. The complications that appeared were: one complete flap necrosis due to venous thrombosis, and five late flap ischemic necroses, in the period from the 10th to 14th postoperative day. Conclusion. Free flap reconstruction of the head and neck is a surgical technique that provides the reconstruction of complex and extensive defects, that could not be performed by using local or regional flaps.

scholarly journals Comprehensive longitudinal microbiome analysis of the chicken cecum reveals a shift from competitive to environmental drivers and a window of opportunity for Campylobacter

2018 ◽  
Author(s):  
Umer Zeeshan Ijaz ◽  
Lojika Sivaloganathan ◽  
Aaron Mckenna ◽  
Anne Richmond ◽  
Carmel Kelly ◽  
...  
Keyword(s):  
Microbial Diversity ◽  
Driving Forces ◽  
Natural Infection ◽  
Environmental Drivers ◽  
Natural Setting ◽  
Window Of Opportunity ◽  
Microbiome Analysis ◽  
Conversion Rates ◽  
Chicken Cecum ◽  
Over Time

AbstractChickens are a key food source for humans yet their microbiome contains bacteria that can be pathogenic to humans, and indeed potentially to chickens themselves. Campylobacter is present within the chicken gut and is the leading cause of bacterial foodborne gastroenteritis within humans worldwide. Infection can lead to secondary sequelae such as Guillain-Barré syndrome and stunted growth in children from low-resource areas. Despite the global health impact and economic burden of Campylobacter, how and when Campylobacter appears within chickens remains unclear. As such, there has been a motivation to decrease the number of Campylobacter within chickens and thus reduce the risk of infection to humans. The lack of day-to-day microbiome data with replicates, relevant metadata, and a lack of natural infection studies have delayed our understanding of the chicken gut microbiome and Campylobacter. Here, we performed a comprehensive day-to-day microbiome analysis of the chicken cecum from day 3 to 35 (12 replicates each day; n=396) combining metadata such as chicken weight and feed conversion rates to investigate what the driving forces are for the microbial changes within the chicken gut over time, and how this relates to Campylobacter appearance within a natural habitat setting. We found a rapidly increasing microbial diversity up to day 12 with variation observed both in terms of genera and abundance, before a stabilisation of the microbial diversity after day 20. In particular, we identified a shift from competitive to environmental drivers of microbial community from days 12 to 20 creating a window of opportunity whereby Campylobacter appears. Campylobacter was identified at day 16 which was one day after the most substantial changes in metabolic profiles observed. In addition, microbial variation over time is most likely influenced by the diet of the chickens whereby significant shifts in OTU abundances and beta dispersion of samples often corresponded with changes in feed. This study is unique in comparison to the most recent studies as neither sampling was sporadic nor Campylobacter was artificially introduced, thus the experiments were performed in a natural setting. We believe that our findings can be useful for future intervention strategies and can help elucidate the mechanism through which Campylobacter within chickens can be reduced.

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