scholarly journals SARS-CoV-2 Antibody persistence in COVID-19 convalescent plasma donors

2021 ◽  
Author(s):  
Clara Di Clara Di Germanio ◽  
Graham Simmons ◽  
Kathleen Kelly ◽  
Rachel Martinelli ◽  
Orsolya Darst ◽  
...  
Keyword(s):  
Direct Detection ◽  
Natural Infection ◽  
Response Duration ◽  
Binding Assays ◽  
Live Virus ◽  
Antibody Persistence ◽  
Broad Institute ◽  
Virus Assay ◽  
Detection Assay ◽  
Rate Of Decline

Background Antibody response duration following SARS-CoV-2 infection tends to be variable and depends on severity of disease and method of detection. Study design and methods COVID-19 convalescent plasma (CCP) from 18 donors was collected longitudinally for a maximum of 63 - 129 days following resolution of symptoms. All the samples were initially screened by the Ortho Total Ig test to confirm positivity and subsequently tested with 7 additional direct sandwich or indirect binding assays (Ortho, Roche, Abbott, Broad Institute) directed against a variety of antigen targets (S1, RBD, and NC), along with 2 neutralization assays (Broad Institute live virus PRNT and Vitalant Research Institute Pseudovirus RVPN). Results The direct detection assays (Ortho Total Ig total and Roche Total Ig) showed increasing levels of antibodies over the time period, in contrast to the indirect IgG assays that showed a decline. Neutralization assays also demonstrated declining responses; the VRI RVPN pseudovirus had a greater rate of decline than the Broad PRNT live virus assay. Discussion These data show that in addition to variable individual responses and associations with disease severity, the detection assay chosen contributes to the heterogeneous results in antibody stability over time. Depending on the scope of the research, one assay may be preferable over another. For serosurveillance studies, direct, double Ag-sandwich assays appear to be the best choice due to their stability; in particular, algorithms that include both S1 and NC based assays can help reduce the rate of false-positivity and discriminate between natural infection and vaccine-derived seroreactivity.

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 Caspofungin and LTX-315 inhibit SARS-CoV-2 replication by targeting the nsp12 polymerase

2020 ◽  
Author(s):  
Min Wang ◽  
Fei Ye ◽  
Jiaqi Su ◽  
Jingru Zhao ◽  
Bin Yuan ◽  
...  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Vero Cells ◽  
Polymerase Activity ◽  
Structural Protein ◽  
Live Virus ◽  
Drug Candidates ◽  
Virtual Screen ◽  
Virus Assay ◽  
Promising Target

Abstract The ongoing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, previously designated as 2019-nCoV) outbreak has caused global concern1. Currently, there are no clinically approved specific drugs or vaccines available for this virus. The viral polymerase is a promising target for developing broad- spectrum antiviral drugs. Here, based on the highly similar structure of SARS- CoV non-structural protein 12 (nsp12) polymerase subunit2, we applied virtual screen for the available compounds, including both the FDA-approved and under- clinic drugs, to identify potential antiviral molecules against SARS-CoV-2. We found two drugs, the clinically approved anti-fungi drug Caspofungin Acetate (Cancidas) and the oncolytic peptide LTX-315, can bind SARS-CoV-2 nsp12 protein to block the polymerase activity in vitro. Further live virus assay revealed that both Caspofungin Acetate and LTX-315 can effectively inhibit SARS-CoV-2 replication in vero cells. These findings present promising drug candidates for treatment of related diseases and would also stimulate the development of pan- coronavirus antiviral agents.Authors Min Wang, Fei Ye, Jiaqi Su, Jingru Zhao, and Bin Yuan contributed equally to this work.

scholarly journals Human Challenge Studies to Accelerate Coronavirus Vaccine Licensure

2020 ◽  
Vol 221 (11) ◽  
pp. 1752-1756 ◽  
Author(s):  
Nir Eyal ◽  
Marc Lipsitch ◽  
Peter G Smith
Keyword(s):  
Natural Infection ◽  
Severe Disease ◽  
Baseline Risk ◽  
Phase 3 ◽  
Live Virus ◽  
Mortality And Morbidity ◽  
Vaccine Candidates ◽  
Frequent Monitoring ◽  
Serious Disease ◽  
Related Mortality

Abstract Controlled human challenge trials of SARS-CoV-2 vaccine candidates could accelerate the testing and potential rollout of efficacious vaccines. By replacing conventional phase 3 testing of vaccine candidates, such trials may subtract many months from the licensure process, making efficacious vaccines available more quickly. Obviously, challenging volunteers with this live virus risks inducing severe disease and possibly even death. However, we argue that such studies, by accelerating vaccine evaluation, could reduce the global burden of coronavirus-related mortality and morbidity. Volunteers in such studies could autonomously authorize the risks to themselves, and their net risk could be acceptable if participants comprise healthy young adults, who are at relatively low risk of serious disease following natural infection, if they have a high baseline risk of natural infection, and if during the trial they receive frequent monitoring and, following any infection, the best available care.

scholarly journals Challenges in vitamin D analysis / Izazovi u analizi vitamina D

2012 ◽  
Vol 31 (4) ◽  
pp. 326-332 ◽  
Author(s):  
Mustafa Serteser ◽  
Abdurrahman Coskun ◽  
Tamer C Inal ◽  
Ibrahim Unsal
Keyword(s):  
Vitamin D ◽  
Clinical Laboratory ◽  
Direct Detection ◽  
Reference Method ◽  
Detection Methods ◽  
Binding Assays ◽  
External Quality Assessment Scheme ◽  
Specificity And Sensitivity ◽  
Competitive Protein Binding ◽  
Phosphorus Levels

Summary Vitamin D is an important determinant for the regulation of calcium and phosphorus levels and mineralization of the bone. The most reliable indicator of vitamin D status is the measurement of plasma or serum 25OH-D concentration. Several studies reported discrepancies between the results of assays. These high variabilities in 25OH-D measurements are due to used assay technologies and lack of standardization against the reference materials. Different assays have been employed for the measurement of 25OHD levels: Competitive Protein Binding Assays, immunoassays, direct detection methods. Choosing an assay platform is important both for clinical laboratory professionals and researchers, and several factors affect this process. Recently, liquid chromatography and tandem mass spectrometry is an alternative method to traditional assays and provides higher specificity and sensitivity than many assays; therefore, it has been suggested as a candidate reference method for circulating 25OH-D3. Standardization of methods for the quantification of 25OH-D by using the human-based samples would reduce the inter-method variability. The best way for laboratories to demonstrate the accuracy of their results is by participating in the external quality assessment scheme. Standardization of the assays is also required to provide clinicians with the accurate tools to diagnose hypovitaminosis. In addition, assay-specific decision limits are needed to define appropriate thresholds of treatment.

scholarly journals Circulating Anti-Wild-Type Adeno-Associated Virus Type 2 (AAV2) Antibodies Inhibit Recombinant AAV2 (rAAV2)-Mediated, but Not rAAV5-Mediated, Gene Transfer in the Brain

2004 ◽  
Vol 78 (12) ◽  
pp. 6344-6359 ◽  
Author(s):  
Carmen S. Peden ◽  
Corinna Burger ◽  
Nicholas Muzyczka ◽  
Ronald J. Mandel
Keyword(s):  
Immune Response ◽  
Virus Type ◽  
Fluorescent Protein ◽  
Natural Infection ◽  
Cell Counting ◽  
Wild Type ◽  
Adeno Associated Virus ◽  
Live Virus ◽  
The Brain

ABSTRACT Epidemiological studies report that 80% of the population maintains antibodies (Ab) to wild-type (wt) adeno-associated virus type 2 (AAV2), with 30% expressing neutralizing Ab (NAb). The blood-brain barrier (BBB) provides limited immune privilege to brain parenchyma, and the immune response to recombinant AAV (rAAV) administration in the brain of a naive animal is minimal. However, central nervous system transduction in preimmunized animals remains unstudied. Vector administration may disrupt the BBB sufficiently to promote an immune response in a previously immunized animal. We tested the hypothesis that intracerebral rAAV administration and readministration would not be affected by the presence of circulating Ab to wt AAV2. Rats peripherally immunized with live wt AAV2 and naive controls were tested with single intrastriatal injections of rAAV2 encoding human glial cell line-derived neurotrophic factor (GDNF) or green fluorescent protein (GFP). Striatal readministration of rAAV2-GDNF was also tested in preimmunized and naive rats. Finally, serotype specificity of the immunization against wt AAV2 was examined by single injections of rAAV5-GFP. Preimmunization resulted in high levels of circulating NAb and prevented transduction by rAAV2 as assessed by striatal GDNF levels. rAAV2-GFP striatal transduction was also prevented by immunization, while rAAV5-GFP-mediated transduction, as assessed by stereological cell counting, was unaffected. Additionally, inflammatory markers were present in those animals that received repeated administrations of rAAV2, including markers of a cell-mediated immune response and cytotoxic damage. A live virus immunization protocol generated the circulating anti-wt-AAV Ab seen in this experiment, while human titers are commonly acquired via natural infection. Regardless, the data show that the presence of high levels of NAb against wt AAV can reduce rAAV-mediated transduction in the brain and should be accounted for in future experiments utilizing this vector.

scholarly journals Antibody persistence and neutralising activity in primary school students and staff: prospective active surveillance, June to December 2020, England

2021 ◽  
Author(s):  
Georgina Ireland ◽  
Anna J Jeffery-Smith ◽  
Maria J Zambon ◽  
Katja Hoschler ◽  
Ross J Harris ◽  
...  
Keyword(s):  
Receptor Binding Domain ◽  
Primary School Students ◽  
School Students ◽  
Neutralising Antibodies ◽  
Live Virus ◽  
Antibody Persistence ◽  
Serological Studies ◽  
Quantitative Results ◽  
June July ◽  
Prospective Longitudinal

Introduction SARS-CoV-2 serological studies have so far focused mainly on adults. Public Health England initiated prospective, longitudinal SARS-CoV-2 sero-surveillance in schools across England after the first national lockdown, which allowed comparison of child and adult responses to SARS-CoV-2 infection over time. Methods Staff and students had venepuncture for SARS-CoV-2 antibodies in school during June, July and December 2020. Blood samples were tested for nucleocapsid (Abbott) and receptor binding domain (RBD) antibodies (in-house assay), and student samples were additionally assessed for live virus neutralising activity. Results In June 2020, 1,344 staff and 835 students were tested. Overall, 11.5% (95% CI: 9.4-13.9) and 11.3% (95% CI: 9.2-13.6; p=0.88) of students had nucleoprotein and RBD antibodies, compared to 15.6% (95% CI: 13.7-17.6) and 15.3% (95% CI: 13.4-17.3; p=0.83) of staff. Live virus neutralising activity was detected in 79.8% (n=71/89) of nucleocapsid and 85.5% (71/83) of RBD antibody positive children. RBD antibodies correlated more strongly with neutralising antibodies (rs=0.7527; p<0.0001) than nucleocapsid antibodies (rs=0.3698; p<0.0001). A median of 24.4 weeks later, 58.2% (107/184) participants had nucleocapsid antibody seroreversion, compared to 20.9% (33/158) for RBD (p<0.001). Similar seroreversion rates were observed between staff and students for nucleocapsid (p=0.26) and RBD-antibodies (p=0.43). Nucleocapsid and RBD antibody quantitative results were significantly lower in staff compared to students (p=0.028 and <0.0001 respectively) at baseline, but not at 24 weeks (p=0.16 and p=0.37, respectively). Conclusion RBD antibodies correlated more strongly with live virus neutralising activity. Most seropositive students and staff retained RBD antibodies for >6 months after SARS-CoV-2 infection.

scholarly journals Metadichol®, a Novel Nano Lipid Formulation that Inhibits SARS-COV-2 and a Multitude of Pathological Viruses in vitro

2020 ◽  
Author(s):  
Palayakotai Raghavan
Keyword(s):  
Lipid Membranes ◽  
Host Cells ◽  
Virus Envelope ◽  
Live Virus ◽  
Lipid Formulation ◽  
Caco2 Cells ◽  
Virus Assay ◽  
Strong Candidate ◽  
Long Chain

Abstract BackgroundNew pathogenic virus outbreaks, occurring with increasing regularity, are leading us to explore novel approaches, which will reduce the reliance on time-consuming vaccine modes to halt the outbreaks. The requirement is to find a universal approach to disarm any new and as yet unknown viruses as they appear. A promising approach could be targeting lipid membranes, which are common to all viruses and bacteria.The ongoing pandemic of severe acute respiratory syndrome-coronavirus 2 (SARS-COV-2) has reaffirmed the importance of interactions between components of the host cell plasma membrane and the virus envelope as a critical mechanism of infection. Metadichol®, a nano lipid emulsion, has been examined and shown to be a strong candidate to help stop the proliferation of SARS-COV-2.Naturally derived substances, such as long-chain saturated lipid alcohols, reduce the infectivity of various types of viruses, including coronaviruses such as SARS-COV-2, by modifying lipid-dependent attachment to human host cells. SARS-COV-2 uses the receptor ACE2 for entry and the serine protease TMPRSS2 for S protein priming. MethodsMetadichol was tested against TMPRSS2 ana ACE2 invitro using commercial available kits. Also it was tested against the live virus in Caco2 cells to test for inhibition of viral replication of SARS-COV-2.ResultsMetadichol®, a nano lipid formulation of long-chain alcohols, has been shown to inhibit TMPRSS2 (EC50 96 ng/ml). Compared to the inhibitor camostat mesylate (EC50 26000 ng/ml), it is 270 times more potent. Additionally, Metadichol® is also a weak inhibitor of ACE2 at 31 µg/ml. Further a live virus assay in Caco2 cells, Metadichol® inhibited SARS-CoV-2 replication with an EC90 of 0.16 µg/ml.ConclusionsMetadichol inhibits SARS-COV-2 virus and since it a non toxic molecule can be easily tested in humans and as it has LD 50 of over 5000 mg/kilo and could help mitigate the crisis facing the world today.

scholarly journals Metadichol®, a Novel Nano Lipid Formulation that Inhibits SARS-COV-2 and a Multitude of Pathological Viruses in vitro

2020 ◽  
Author(s):  
Palayakotai Raghavan
Keyword(s):  
Lipid Membranes ◽  
Host Cells ◽  
Virus Envelope ◽  
Live Virus ◽  
Lipid Formulation ◽  
Virus Assay ◽  
Cell Plasma ◽  
Strong Candidate ◽  
Long Chain

Abstract New pathogenic virus outbreaks, occurring with increasing regularity, are leading us to explore novel approaches, which will reduce the reliance on time-consuming vaccine modes to halt the outbreaks. The requirement is to find a universal approach to disarm any new and as yet unknown viruses as they appear. A promising approach could be targeting lipid membranes, which are common to all viruses and bacteria.The ongoing pandemic of severe acute respiratory syndrome-coronavirus 2 (SARS-COV-2) has reaffirmed the importance of interactions between components of the host cell plasma membrane and the virus envelope as a critical mechanism of infection. Metadichol®, a nano lipid emulsion, has been examined and shown to be a strong candidate to help stop the proliferation of SARS-COV-2.Naturally derived substances, such as long-chain saturated lipid alcohols, reduce the infectivity of various types of viruses, including coronaviruses such as SARS-COV-2, by modifying lipid-dependent attachment to human host cells. SARS-COV-2 uses the receptor ACE2 for entry and the serine protease TMPRSS2 for S protein priming.Metadichol®, a nano lipid formulation of long-chain alcohols, has been shown to inhibit TMPRSS2 (EC50 96 ng/ml). Compared to the inhibitor camostat mesylate (EC50 26000 ng/ml), it is 270 times more potent. Additionally, Metadichol® is also a extremely weak inhibitor of ACE2 at 31 µg/ml. Further a live virus assay in Caco2 cells, Metadichol® inhibited SARS-CoV-2 replication with an EC90 of 0.16 µg/ml.

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