scholarly journals Rapid in vitro assays for screening neutralizing antibodies and antivirals against SARS-CoV-2

2020 ◽  
Author(s):  
Jun-Gyu Park ◽  
Fatai S. Oladduni ◽  
Kevin Chiem ◽  
Chengjin Ye ◽  
Michael Pipenbrink ◽  
...  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Neutralizing Antibodies ◽  
Health Impact ◽  
In Vitro Assays ◽  
Global Pandemic ◽  
Novel Coronavirus ◽  
Human Infections ◽  
Identification And Characterization

AbstractTowards the end of 2019, a novel coronavirus (CoV) named severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), genetically similar to severe acute respiratory syndrome coronavirus-1 (SARS-CoV-1), emerged in Wuhan, Hubei province of China, and has been responsible of coronavirus disease 2019 (COVID-19) in humans. Since its first report, SARS-CoV-2 has resulted in a global pandemic, with over 10 million human infections and over 560,000 deaths reported worldwide at the end of June 2020. Currently, there are no United States (US) Food and Drug Administration (FDA)-approved vaccines and/or antivirals licensed against SARS-CoV-2, and the high economical and health impact of SARS-CoV-2 has placed global pressure on the scientific community to identify effective prophylactic and therapeutic treatments for the treatment of SARS-CoV-2 infection and associated COVID-19 disease. While some compounds have been already reported to reduce SARS-CoV-2 infection and a handful of monoclonal antibodies (mAbs) have been described that neutralize SARS-CoV-2, there is an urgent need for the development and standardization of assays which can be used in high through-put screening (HTS) settings to identify new antivirals and/or neutralizing mAbs against SARS-CoV-2. Here, we described a rapid, accurate and highly reproducible plaque reduction microneutralization (PRMNT) assay that can be quickly adapted for the identification and characterization of both neutralizing mAbs and antivirals against SARS-CoV-2. Importantly, our MNA is compatible with HTS settings to interrogate large and/or complex libraries of mAbs and/or antivirals to identify those with neutralizing and/or antiviral activity, respectively, against SARS-CoV-2.

scholarly journals Comparison of Four SARS-CoV-2 Neutralization Assays

Vaccines ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 13
Author(s):  
Lydia Riepler ◽  
Annika Rössler ◽  
Albert Falch ◽  
André Volland ◽  
Wegene Borena ◽  
...  
Keyword(s):  
Vesicular Stomatitis Virus ◽  
Neutralizing Antibodies ◽  
The Other ◽  
In Vitro Assays ◽  
The Novel ◽  
Effective Protection ◽  
Vaccine Candidates ◽  
Vesicular Stomatitis ◽  
Novel Coronavirus

Neutralizing antibodies are a major correlate of protection for many viruses including the novel coronavirus SARS-CoV-2. Thus, vaccine candidates should potently induce neutralizing antibodies to render effective protection from infection. A variety of in vitro assays for the detection of SARS-CoV-2 neutralizing antibodies has been described. However, validation of the different assays against each other is important to allow comparison of different studies. Here, we compared four different SARS-CoV-2 neutralization assays using the same set of patient samples. Two assays used replication competent SARS-CoV-2, a focus forming assay and a TCID50-based assay, while the other two assays used replication defective lentiviral or vesicular stomatitis virus (VSV)-based particles pseudotyped with SARS-CoV-2 spike. All assays were robust and produced highly reproducible neutralization titers. Titers of neutralizing antibodies correlated well between the different assays and with the titers of SARS-CoV-2 S-protein binding antibodies detected in an ELISA. Our study showed that commonly used SARS-CoV-2 neutralization assays are robust and that results obtained with different assays are comparable.

scholarly journals Screening Assays for Epigenetic Targets Using Native Histones as Substrates

2011 ◽  
Vol 17 (1) ◽  
pp. 18-26 ◽  
Author(s):  
Alexander-Thomas Hauser ◽  
Elisabeth-Maria Bissinger ◽  
Eric Metzger ◽  
Antje Repenning ◽  
Uta-Maria Bauer ◽  
...  
Keyword(s):  
In Vitro Assays ◽  
The Past ◽  
Chemistry Research ◽  
Core Histones ◽  
Homogeneous Assay ◽  
Screening Assays ◽  
Set Up ◽  
Identification And Characterization

In the past years, a lot of attention has been given to the identification and characterization of selective and potent inhibitors of chromatin-modifying enzymes to better understand their specific role in transcriptional regulation. As aberrant histone methylation is involved in different pathological processes, the search for methyltransferase and demethylase inhibitors has emerged as a crucial issue in current medicinal chemistry research. High-throughput in vitro assays are important tools for the identification of new methyltransferase or demethylase inhibitors. These usually use oligopeptide substrates derived from histone sequences, although in many cases, they are not good substrates for these enzymes. Here, the authors report about the setup and establishment of in vitro assays that use native core histones as substrates, enabling an assay environment that better resembles native conditions. They have applied these substrates for the known formaldehyde dehydrogenase assay for the histone demethylase LSD1 and have established two new antibody-based assays. For LSD1, a heterogeneous assay format was set up, and a homogeneous assay was used for the characterization of the arginine methyltransferase PRMT1. Validation of the system was achieved with reference inhibitors in each case.

scholarly journals Characterization of the emerging B.1.621 variant of interest of SARS-CoV-2

2021 ◽  
Author(s):  
Katherine Laiton-Donato ◽  
Carlos Franco-Munoz ◽  
Diego Alejandro Alvarez-Diaz ◽  
Hector Ruiz-Moreno ◽  
Jose Usme-Ciro ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Natural Infection ◽  
Health Impact ◽  
Receptor Binding Domain ◽  
Biological Assays ◽  
The Public ◽  
Virus Escape ◽  
Potential Impact

The SARS-CoV-2 genetic diversification has a potential impact in the virus escape from natural infection- or vaccine-elicited neutralizing antibodies and higher transmissibility. Here we report the emergence of novel B.1.621 variant of interest with the insertion 145N in the N-terminal domain and amino acid change N501Y, E484K, and P681H in the Receptor Binding Domain of the Spike protein. Further studies in vitro biological assays and epidemiologic analysis will allow evaluating the public health impact of B.1.621 variant.

scholarly journals Coronavirus Pandemic: An Update on the Transmission, Diagnosis, Clinical Features and Managment

2021 ◽  
pp. 182-192
Author(s):  
Saad S. Alqahtani ◽  
Santhosh Joseph ◽  
Otilia J. F. Banji ◽  
Abdulkarim M. Meraya ◽  
Ahmed A. Albarraq ◽  
...  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
The Novel ◽  
Highly Pathogenic ◽  
Treatment Protocols ◽  
Vaccination Programs ◽  
Global Pandemic ◽  
Mesh Terms ◽  
Novel Coronavirus ◽  
Human Infections ◽  
Widespread Interest

The novel coronavirus, designated as “Severe Acute Respiratory Syndrome Coronavirus 2” (SARS-CoV-2), is a new coronavirus that has evolved as a global pandemic recently, and it has created a widespread interest in coronaviruses causing human infections. This article compares the pathogenesis, distribution, clinical characteristics, and treatment of the three highly pathogenic coronaviruses that caused epidemics, namely, “Severe Acute Respiratory Syndrome Coronavirus” (SARS), “Middle East Respiratory Syndrome” (MERS), and SARS-CoV-2. This narrative review is prepared using the data compiled from literature search using relevant MeSH terms. The clinical manifestation of SARS-CoV-2 infection (COVID-19) is mild with relatively low fatality rate than the other two coronaviruses; however, its overall capability to cause explosive spread of the disease and reach a pandemic level is greater. Unlike SARS and MERS, COVID-19 has no accepted treatment protocols at present. Extensive studies and analyses on COVID-19 are necessary before making strong recommendations for or against any particular treatment, although some recent medications have shown great potential. COVID-19 still needs further investigation, where all of the lessons gained from previous outbreaks of SARS and MERS and the experience from the countries that managed COVID-19 seem to be the best approaches to counteract this new global hazard at present until effective preventive vaccines are available in sufficient quantity for mass vaccination programs worldwide.

Synthetic and semi-synthetic drugs as promising therapeutic option for the treatment of COVID-19

2020 ◽  
Vol 20 ◽  
Author(s):  
Ekta Shirbhate ◽  
Preeti Patel ◽  
Vijay K Patel ◽  
Ravichandran Veerasamy ◽  
Prabodh C Sharma ◽  
...  
Keyword(s):  
Therapeutic Option ◽  
Antiviral Treatment ◽  
The Novel ◽  
Clinical Experiences ◽  
Synthetic Compounds ◽  
Synthetic Drugs ◽  
Global Pandemic ◽  
The World ◽  
Novel Coronavirus

: The novel coronavirus disease-19 (COVID-19), a global pandemic that emerged from Wuhan, China has today travelled all around the world, so far 216 countries or territories with 21,732,472 people infected and 770,866 deaths globally (as per WHO COVID-19 update dated August 18, 2020). Continuous efforts are being made to repurpose the existing drugs and develop vaccines for combating this infection. Despite, to date, no certified antiviral treatment or vaccine prevails. Although, few candidates have displayed their efficacy in in vitro studies and are being repurposed for COVID-19 treatment. This article summarizes synthetic and semi-synthetic compounds displaying potent activity in their clinical experiences or studies against COVID-19 and also focuses on mode of action of drugs being repositioned against COVID-19.

scholarly journals Functional Characterization of the mazEF Toxin-Antitoxin System in the Pathogenic Bacterium Agrobacterium tumefaciens

2021 ◽  
Vol 9 (5) ◽  
pp. 1107
Author(s):  
Wonho Choi ◽  
Yoshihiro Yamaguchi ◽  
Ji-Young Park ◽  
Sang-Hyun Park ◽  
Hyeok-Won Lee ◽  
...  
Keyword(s):  
Agrobacterium Tumefaciens ◽  
Physiological Function ◽  
Functional Characterization ◽  
Site Directed Mutagenesis ◽  
In Vitro Assays ◽  
Cell Growth Inhibition ◽  
The Right

Agrobacterium tumefaciens is a pathogen of various plants which transfers its own DNA (T-DNA) to the host plants. It is used for producing genetically modified plants with this ability. To control T-DNA transfer to the right place, toxin-antitoxin (TA) systems of A. tumefaciens were used to control the target site of transfer without any unintentional targeting. Here, we describe a toxin-antitoxin system, Atu0939 (mazE-at) and Atu0940 (mazF-at), in the chromosome of Agrobacterium tumefaciens. The toxin in the TA system has 33.3% identity and 45.5% similarity with MazF in Escherichia coli. The expression of MazF-at caused cell growth inhibition, while cells with MazF-at co-expressed with MazE-at grew normally. In vivo and in vitro assays revealed that MazF-at inhibited protein synthesis by decreasing the cellular mRNA stability. Moreover, the catalytic residue of MazF-at was determined to be the 24th glutamic acid using site-directed mutagenesis. From the results, we concluded that MazF-at is a type II toxin-antitoxin system and a ribosome-independent endoribonuclease. Here, we characterized a TA system in A. tumefaciens whose understanding might help to find its physiological function and to develop further applications.

scholarly journals A Bacterially-Expressed Recombinant Envelope Protein from Usutu Virus Induces Neutralizing Antibodies in Rabbits

Vaccines ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 157
Author(s):  
Kinga Böszörményi ◽  
Janet Hirsch ◽  
Gwendoline Kiemenyi Kayere ◽  
Zahra Fagrouch ◽  
Nicole Heijmans ◽  
...  
Keyword(s):  
Envelope Protein ◽  
Neutralizing Antibodies ◽  
Size Exclusion ◽  
Vitro Assay ◽  
Usutu Virus ◽  
Transmission Electron ◽  
Exclusion Chromatography ◽  
Efficacious Vaccine ◽  
Human Infections

Background: Recently, an emerging flavivirus, Usutu virus (USUV), has caused an epidemic among birds in Europe, resulting in a massive die-off in Eurasian blackbirds. Currently found only in Europe and Africa, it can be envisioned that Usutu virus will follow the path of other flaviviruses, like West Nile virus and Zika virus, and will spread via its mosquito vectors and bird hosts to other parts of the world. Several cases of human infections by Usutu virus have already been published. Anticipating this spread, development of an efficacious vaccine would be highly desirable. Method: This study describes the production in E. coli, purification, and refolding of a partial USUV envelope protein. Prior to immunization, the protein was characterized using size exclusion chromatography, transmission electron microscopy and dynamic light scattering, showing the limited presence of virus-like structures, indicating that the protein solution is probably a mixture of mono and multimeric envelope proteins. Results: Immunizations of two rabbits with the refolded E-protein fraction, mixed with a strong adjuvant, resulted in the generation of neutralizing antibodies, as evidenced in an in vitro assay. Discussion: The way forward towards a subunit vaccine against Usutu virus infection is discussed.

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