Enhanced production yields of rVSV-SARS-CoV-2 vaccine using Fibra-Cel macrocarriers.

The COVID-19 pandemic has led to high global demand for vaccines to safeguard public health. To that end, our institute has developed a recombinant viral vector vaccine utilizing a modified vesicular stomatitis virus (VSV) construct, wherein the G protein of VSV is replaced with the spike protein of SARS-CoV-2 (rVSV-ΔG-spike). Previous studies have demonstrated the production of a VSV-based vaccine in Vero cells adsorbed on Cytodex 1 microcarriers or in suspension.

Development and Validation of an Innovative Analytical Approach for the Quantitation of Tris(Hydroxymethyl)Aminomethane (TRIS) in Pharmaceutical Formulations by Liquid Chromatography Tandem Mass Spectrometry.

A novel COVID-19 vaccine (BriLife®) has been developed by the Israel Institute for Biological Research (IIBR) to prevent the spread of the SARS-CoV-2 virus throughout the population in Israel. One of the components in the vaccine formulation is tris(hydroxymethyl)aminomethane (tromethamine, TRIS), a buffering agent. TRIS is a commonly used excipient in various approved parenteral medicinal products, including the mRNA COVID-19 vaccines produced by Pfizer/BioNtech and Moderna.

Immunologic and Protective Properties of Subunit- vs. Whole Toxoid-Derived Anti-Botulinum Equine Antitoxin.

Botulism is a paralytic disease caused by botulinum neurotoxins (BoNTs). Equine antitoxin is currently the standard therapy for botulism in human. The preparation of equine antitoxin relies on the immunization of horses with botulinum toxoid, which suffers from low yield and safety limitations.

Centaur antibodies: Engineered chimeric equine-human recombinant antibodies.

Hyper-immune antisera from large mammals, in particular horses, are routinely used for life-saving anti-intoxication intervention. While highly efficient, the use of these immunotherapeutics is complicated by possible recipient reactogenicity and limited availability. Accordingly, there is an urgent need for alternative improved next-generation immunotherapies to respond to this issue of high public health priority.

High Cell Density Cultivation Process for the Expression of Botulinum Neurotoxin a Receptor Binding Domain.

The receptor-binding domain of botulinum neurotoxin (H fragment), is a promising botulism vaccine candidate. In the current study, fermentation strategies were evaluated to upscale H fragment expression. A simple translation of the growth conditions from shake flasks to a batch fermentation process resulted in limited culture growth and protein expression (OD of 11 and volumetric protein yields of 123 mg/L).

Highly Specific Monoclonal Antibody Targeting the Botulinum Neurotoxin Type E Exposed SNAP-25 Neoepitope.

Botulinum neurotoxin type E (BoNT/E), the fastest acting toxin of all BoNTs, cleaves the 25 kDa synaptosomal-associated protein (SNAP-25) in motor neurons, leading to flaccid paralysis. The specific detection and quantification of the BoNT/E-cleaved SNAP-25 neoepitope can facilitate the development of cell-based assays for the characterization of anti-BoNT/E antibody preparations. In order to isolate highly specific monoclonal antibodies suitable for the in vitro immuno-detection of the exposed neoepitope, mice and rabbits were immunized with an eight amino acid peptide composed of the C-terminus of the cleaved SNAP-25.

Neutralization of SARS-CoV-2 Variants by rVSV-ΔG-Spike-Elicited Human Sera.

The emergence of rapidly spreading variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) poses a major challenge to the ability of vaccines and therapeutic antibodies to provide immunity. These variants contain mutations of specific amino acids that might impede vaccine efficacy. BriLife (rVSV-ΔG-spike) is a newly developed SARS-CoV-2 vaccine candidate currently in phase II clinical trials.

A cell-based alternative to the mouse potency assay for pharmaceutical type E botulinum antitoxins.

The pharmacopeia mouse neutralization assay (PMNA) is the standard method for determining the potency of phar­maceutical botulinum antitoxins. However, a PMNA requires a large number of mice, and, thus, an alternative in vitro method to replace it is needed. Herein, we developed an in vitro SiMa cell line-based neutralization assay (SBNA), compatible with a PMNA design, for therapeutic antitoxins against type E botulinum neurotoxin (BoNT/E).

A Rabbit Model for the Evaluation of Drugs for Treating the Chronic Phase of Botulism.

Antitoxin, the only licensed drug therapy for botulism, neutralizes circulating botulinum neurotoxin (BoNT). However, antitoxin is no longer effective when a critical amount of BoNT has already entered its target nerve cells. The outcome is a chronic phase of botulism that is characterized by prolonged paralysis.

Small Molecule Receptor Binding Inhibitors with In Vivo Efficacy against Botulinum Neurotoxin Serotypes A and E.

Botulinum neurotoxins (BoNTs) are the most poisonous substances in nature. Currently, the only therapy for botulism is antitoxin. This therapy suffers from several limitations and hence new therapeutic strategies are desired.

Identification of SARS-CoV-2 Receptor Binding Inhibitors by In Vitro Screening of Drug Libraries.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for the coronavirus disease 2019 (COVID-19) global pandemic. The first step of viral infection is cell attachment, which is mediated by the binding of the SARS-CoV-2 receptor binding domain (RBD), part of the virus spike protein, to human angiotensin-converting enzyme 2 (ACE2). Therefore, drug repurposing to discover RBD-ACE2 binding inhibitors may provide a rapid and safe approach for COVID-19 therapy.

A Novel Running Wheel Mouse Model for Botulism and Its Use for the Evaluation of Postsymptom Antitoxin Efficacy.

Antitoxin is currently the only approved therapy for botulinum intoxications. The efficacy of antitoxin preparations is evaluated in animals. However, while in practice antitoxin is administered to patients only after symptom onset, in most animal studies, it is tested in relation to time postintoxication.

A Rabbit Model for Prolonged Continuous Intravenous Infusion Via a Peripherally Inserted Central Catheter.

Medical treatment may require the continuous intravenous (IV) infusion of drugs to sustain the therapeutic blood concentration and to minimize dosing errors. Animal disease models that ultimately mimic the intended use of new potential drugs via a continuous IV infusion in unrestrained, free roaming animals are required. While peripherally inserted central catheters (PICCs) and other central line techniques for prolonged IV infusion of drugs are prevalent in the clinic, continuous IV infusion methods in an animal model are challenging and limited.

New approach for the rational selection of markers to identify botulinum toxins.

The application of mass spectrometry (MS) to detect unique peptide markers has been widely employed as a means of identifying bacterial proteins. Botulinum neurotoxins (BoNTs) are bacterial proteins that cause the life-threatening disease botulism. BoNTs are divided into several antigenically distinct serotypes and several dozen subtypes.

A single dose of recombinant VSV-∆G-spike vaccine provides protection against SARS-CoV-2 challenge.

The COVID-19 pandemic caused by SARS-CoV-2 imposes an urgent need for rapid development of an efficient and cost-effective vaccine, suitable for mass immunization. Here, we show the development of a replication competent recombinant VSV-∆G-spike vaccine, in which the glycoprotein of VSV is replaced by the spike protein of SARS-CoV-2. In-vitro characterization of this vaccine indicates the expression and presentation of the spike protein on the viral membrane with antigenic similarity to SARS-CoV-2.

Post-Exposure Anti-Ricin Treatment Protects Swine Against Lethal Systemic and Pulmonary Exposures.

Ricin, a plant-derived toxin originating from the seeds of (castor bean plant), is one of the most lethal toxins known. To date, there is no approved post-exposure therapy for ricin exposures. This work demonstrates for the first time the therapeutic efficacy of equine-derived anti-ricin F(ab') antibodies against lethal pulmonary and systemic ricin exposures in swine.

Studying the differential efficacy of postsymptom antitoxin treatment in type A versus type B botulism using a rabbit spirometry model.

Botulinum neurotoxin (BoNT) serotypes A, B and E are responsible for most cases of human botulism. The only approved therapy for botulism is antitoxin treatment administered to patients after symptom onset. However, a recent meta-analysis of antitoxin efficacy in human botulism cases over the past century concluded that a statistically significant reduction in mortality is associated with the use of type E and type A antitoxin, but not with type B antitoxin.

A Novel Rabbit Spirometry Model of Type E Botulism and Its Use for the Evaluation of Postsymptom Antitoxin Efficacy.

Botulinum neurotoxins (BoNTs), the most poisonous substances known in nature, pose significant concern to health authorities. The only approved therapeutic for botulism is antitoxin. While administered to patients only after symptom onset, antitoxin efficacy is evaluated in animals mostly in relation to time postintoxication regardless of symptoms.

An in vitro cell-based potency assay for pharmaceutical type A botulinum antitoxins.

Botulism therapy relies on passive immunization with antitoxin. The mouse neutralization test is the only pharmacopeia assay to measure the potency of antitoxin preparations. Herein, we present an in vitro cell-based assay for the measurement of pharmaceutical type A antitoxin potency.

Development of a multiplex Endopep-MS assay for simultaneous detection of botulinum toxins A, B and E.

Botulinum neurotoxins (BoNTs) are bacterial proteins that cause botulism, a life-threatening disease. The Endopep-MS assay permits rapid detection and serotypic differential diagnosis of BoNTs. The serotype-specific nature of this assay requires that each serum sample be aliquoted and individually tested, which in addition to the limited volume of clinical samples, especially in infants, points to the need for a multiplex assay.

Role of Homologous Fc Fragment in the Potency and Efficacy of Anti-Botulinum Antibody Preparations.

The only approved treatment for botulism relies on passive immunity which is mostly based on antibody preparations collected from hyper-immune horses. The IgG Fc fragment is commonly removed from these heterologous preparations to reduce the incidence of hyper-sensitivity reactions. New-generation therapies entering the pipeline are based on a combination of humanized monoclonal antibodies (MAbs), which exhibit improved safety and pharmacokinetics.

Optimization of SNAP-25-derived peptide substrate for improved detection of botulinum A in the Endopep-MS assay.

Botulinum neurotoxins (BoNTs) are the most toxic proteins in nature. Endopeptidase-mass-spectrometry (Endopep-MS) is used as a specific and rapid in-vitro assay to detect BoNTs. In this assay, immunocaptured toxin cleaves a serotype-specific-peptide-substrate, and the cleavage products are then detected by MS.