Efficacy of inactivation of viral contaminants in hyperimmune horse plasma against botulinum toxin by low pH alone and combined with pepsin digestion

Torgeman, Amram; Mador, Nurit; Dorozko, Marina; Eschar, Naomi; White, Moshe D.; Wolf, Dana; Epstein, Eyal

doi:10.1016/j.biologicals.2017.06.003

Cited by 10 publications

(8 citation statements)

References 10 publications

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“…Hyperimmune plasma was collected from horses immunized with a toxoid preparation that was obtained by dialyzing the toxin complex against 0.14% formalin at 35 • C for 2 weeks [43]. The fragment crystallizable (Fc) region was removed by pepsin digestion [44], and the neutralizing activity of the purified F(ab')2 antitoxin was determined according to the European Pharmacopeia [45]. In summary, serial 1.2-fold dilutions of each antitoxin preparation were prepared.…”

Section: Antitoxinmentioning

confidence: 99%

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

Torgeman

Diamant

Dor

et al. 2021

Toxins

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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. In this stage, blocking toxin activity within cells by next-generation intraneuronal anti-botulinum drugs (INABDs) may shorten the chronic phase of the disease and accelerate recovery. However, there is a lack of adequate animal models that simulate the chronic phase of botulism for evaluating the efficacy of INABDs. Herein, we report the development of a rabbit model for the chronic phase of botulism, induced by intoxication with a sublethal dose of BoNT. Spirometry monitoring enabled us to detect deviations from normal respiration and to quantitatively define the time to symptom onset and disease duration. A 0.85 rabbit intramuscular median lethal dose of BoNT/A elicited the most consistent and prolonged disease duration (mean = 11.8 days, relative standard deviation = 27.9%) that still enabled spontaneous recovery. Post-exposure treatment with antitoxin at various time points significantly shortened the disease duration, providing a proof of concept that the new model is adequate for evaluating novel therapeutics for botulism.

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Section: Antitoxinmentioning

confidence: 99%

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

Torgeman

Diamant

Dor

et al. 2021

Toxins

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“…Viral safety of biological products derived from equine plasma is verified by testing the starting material of the process (hyperimmune horse plasma) for viral contamination 22 and by assessing the efficacy of the entire production process to inactivate infectious viruses 23 . As part of such a process, batches of plasma obtained from a hyperimmune horse, producing anti-botulinum antibodies, were routinely inspected for viruses by incubating the plasma in Vero and BHK cell lines and monitoring them for cytopathic effect (CPE).…”

Section: Resultsmentioning

confidence: 99%

Identification and genetic characterization of a novel Orthobunyavirus species by a straightforward high-throughput sequencing-based approach

Shifman

Cohen-Gihon

Beth-Din

et al. 2019

Sci Rep

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Identification and characterization of novel unknown viruses is of great importance. The introduction of high-throughput sequencing (HTS)-based methods has paved the way for genomics-based detection of pathogens without any prior assumptions about the characteristics of the organisms. However, the use of HTS for the characterization of viral pathogens from clinical samples remains limited. Here, we report the identification of a novel Orthobunyavirus species isolated from horse plasma. The identification was based on a straightforward HTS approach. Following enrichment in cell culture, RNA was extracted from the growth medium and rapid library preparation, HTS and primary bioinformatic analyses were performed in less than 12 hours. Taxonomical profiling of the sequencing reads did not reveal sequence similarities to any known virus. Subsequent application of de novo assembly tools to the sequencing reads produced contigs, of which three showed some similarity to the L, M, and S segments of viruses belonging to the Orthobunyavirus genus. Further refinement of these contigs resulted in high-quality, full-length genomic sequences of the three genomic segments (L, M and S) of a novel Orthobunyavirus . Characterization of the genomic sequence, including the prediction of open reading frames and the inspection of consensus genomic termini and phylogenetic analysis, further confirmed that the novel virus is indeed a new species, which we named Ness Ziona virus.

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“…Horse anti-BoNT/A or anti-BoNT/B plasma were collected from hyperimmune animals immunized with toxoid prepared by dialyzing the toxin complex against 0.14% formalin at 35°C for 2 weeks ( Diamant et al, 2014 ). The Fc fragment was removed by pepsin digestion ( Torgeman et al, 2017 ) and purified F(ab)′ 2 antitoxin-neutralizing activity was determined according to the European Pharmacopeia ( European Directorate for the Quality of Medicines and Healthcare, 2014 ). Briefly, serial 1.2-fold dilutions of each antitoxin preparation were prepared.…”

Section: Methodsmentioning

confidence: 99%

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

Torgeman

Schwartz

Diamant

et al. 2018

Disease Models &Amp; Mechanisms

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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. Animal models could be highly valuable in studying postsymptom antitoxin efficacy (PSAE). However, the few attempts to evaluate PSAE in animals relied on subjective observations and showed ∼50% protection. Recently, we developed a novel spirometry model for the quantitative evaluation of PSAE in rabbits and used it to demonstrate full protection against BoNT/E. In the current study, a comparative evaluation of PSAE in botulism types A and B was conducted using this quantitative respiratory model. A lethal dose of each toxin induced a comparable course of disease both in terms of time to symptoms (TTS, 41.9±1.3 and 40.6±1.1 h, respectively) and of time to death (TTD, 71.3±3.1 and 66.3±1.7 h, respectively). However, in accordance with the differential serotypic PSAE observed in humans, postsymptom antitoxin treatment was fully effective only in BoNT/A-intoxicated rabbits. This serotypic divergence was reflected by a positive and statistically significant correlation between TTS and TTD in BoNT/A-intoxicated rabbits (r=0.91, P=0.0006), but not in those intoxicated with BoNT/B (r=0.06, P=0.88). The rabbit spirometry system might be useful in the evaluation toolkit of botulism therapeutics, including those under development and intended to act when antitoxin is no longer effective.

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Efficacy of inactivation of viral contaminants in hyperimmune horse plasma against botulinum toxin by low pH alone and combined with pepsin digestion

Cited by 10 publications

References 10 publications

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

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

Identification and genetic characterization of a novel Orthobunyavirus species by a straightforward high-throughput sequencing-based approach

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

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