Characterization of Botulinum Neurotoxin Type A Neutralizing Monoclonal Antibodies and Influence of Their Half-Lives on Therapeutic Activity

Mazuet, Christelle; Dano, Julie; Popoff, Michel R.; Créminon, Christophe; Volland, Hervé

doi:10.1371/journal.pone.0012416

Cited by 33 publications

(40 citation statements)

References 33 publications

(38 reference statements)

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“…Intact MAbs and their F(ab′) 2 fragments were administered in equimolar concentrations in respect to their binding titer to rule out any bias as a result of differences in functional binding. Our observations are not entirely consistent with results reported by Mazuet et al, who conducted a BoNT toxicity study with two MAbs; one F(ab′) 2 fragment exerted less protection in mice, while the other F(ab′) 2 fragment retained the neutralization efficacy of its intact IgG, despite the clearly longer half-lives for both intact IgGs in the blood [29]. Interestingly, the MAb that was not affected by the Fc fragment deletion in the Mazuet et al study displayed a neutralization activity that was comparable to that of a PAb preparation [29].…”

Section: Discussionsupporting

confidence: 59%

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

Torgeman

Ozeri

David

et al. 2017

Toxins

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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. In the current study, a systematic and quantitative approach was applied to measure the direct contribution of homologous Fc to the potency of monoclonal and polyclonal antitoxin preparations in mice. Homologous Fc increased the potency of three individual anti-botulinum toxin MAbs by up to one order of magnitude. Moreover, Fc fragment removal almost completely abolished the synergistic potency obtained from a combined preparation of these three MAbs. The MAb mixture neutralized a 400-mouse median lethal dose (MsLD50) of botulinum toxin, whereas the F(ab′)2 combination failed to neutralize 10 MsLD50 of botulinum toxin. Notably, increased avidity did not compensate for this phenomenon, as a polyclonal, hyper-immune, homologous preparation lost 90% of its potency as well upon Fc removal. Finally, the addition of homologous Fc arms to a heterologous pharmaceutical anti-botulinum toxin polyclonal horse F(ab′)2 preparation improved its efficacy when administered to intoxicated symptomatic mice. Our study extends the aspects by which switching from animal-based to human-based antitoxins will improve not only the safety but also the potency and efficacy of passive immunity against toxins.

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Section: Discussionsupporting

confidence: 59%

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

Torgeman

Ozeri

David

et al. 2017

Toxins

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“…In addition, multilocus sequence type (MLST) profiling analysis showed that the A3 strain is clearly distinguished from other subtype A strains (15). Of considerable interest is that BoNT/A3 was found to be less effectively neutralized by antiBoNT/A1 antibody (22). However, the purification of BoNT/A3 presented considerable challenges.…”

Section: Discussionmentioning

confidence: 99%

“…BoNT/A3 is not effectively neutralized by antiBoNT/A1 antibodies (J. Marks, personal communication; 22), which indicates that certain epitopes responsible for neutralization are different between BoNT/A1 and BoNT/A3. This difference in immunogenicity leads to the possibility that BoNT/A3 could potentially replace BoNT/A1 for those patients who have developed neutralizing antibodies to BoNT/A1 due to repeated treatments or immunization with BoNT/A1.…”

mentioning

confidence: 99%

Purification and Characterization of a Novel Subtype A3 Botulinum Neurotoxin

Tepp

Lin

Johnson

2012

Appl Environ Microbiol

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Botulinum neurotoxins (BoNTs) produced by Clostridium botulinum are of considerable importance due to their being the cause of human and animal botulism, their potential as bioterrorism agents, and their utility as important pharmaceuticals. Type A is prominent due to its high toxicity and long duration of action. Five subtypes of type A BoNT are currently recognized; BoNT/A1, -/A2, and -/A5 have been purified, and their properties have been studied. BoNT/A3 is intriguing because it is not effectively neutralized by polyclonal anti-BoNT/A1 antibodies, and thus, it may potentially replace BoNT/A1 for patients who have become refractive to treatment with BoNT/A1 due to antibody formation or other modes of resistance. Purification of BoNT/A3 has been challenging because of its low levels of production in culture and the need for innovative purification procedures. In this study, modified Mueller-Miller medium was used in place of traditional toxin production medium (TPM) to culture C. botulinum A3 (CDC strain) and boost toxin production. BoNT/A3 titers were at least 10-fold higher than those produced in TPM. A purification method was developed to obtain greater than 95% pure BoNT/A3. The specific toxicity of BoNT/A3 as determined by mouse bioassay was 5.8 ؋ 10 7 50% lethal doses (LD 50 )/mg. Neutralization of BoNT/A3 toxicity by a polyclonal anti-BoNT/A1 antibody was approximately 10-fold less than the neutralization of BoNT/A1 toxicity. In addition, differences in symptoms were observed between mice that were injected with BoNT/A3 and those that were injected with BoNT/A1. These results indicate that BoNT/A3 has novel biochemical and pharmacological properties compared to those of other subtype A toxins.

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“…Similar experiments investigating symptoms of intoxication have not been conducted for other subtypes. Additionally, various investigators have shown differences in the ability of monoclonal and polyclonal antibodies to bind to or neutralize various subtypes within the same serotype (23,(25)(26)(27).…”

mentioning

confidence: 99%

Characterization of Botulinum Neurotoxin A Subtypes 1 Through 5 by Investigation of Activities in Mice, in Neuronal Cell Cultures, and In Vitro

et al. 2013

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Botulinum neurotoxins (BoNTs) are synthesized by Clostridium botulinum and exist as seven immunologically distinct serotypes designated A through G. For most serotypes, several subtypes have now been described based on nominal differences in the amino acid sequences. BoNT/A1 is the most well-characterized subtype of the BoNT/A serotype, and many of its properties, including its potency, its prevalence as a food poison, and its utility as a pharmaceutical, have been thoroughly studied. In contrast, much remains unknown of the other BoNT/A subtypes. In this study, BoNT/A subtype 1 (BoNT/A1) to BoNT/A5 were characterized utilizing a mouse bioassay, an in vitro cleavage assay, and several neuronal cell-based assays. The data indicate that BoNT/A1 to -5 have distinct in vitro and in vivo toxicological properties and that, unlike those for BoNT/A1, the neuronal and mouse results for BoNT/A2 to -5 do not correlate with their enzymatic activity. These results indicate that BoNT/A1 to -5 have distinct characteristics, which are of importance for a greater understanding of botulism and for pharmaceutical applications.

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Characterization of Botulinum Neurotoxin Type A Neutralizing Monoclonal Antibodies and Influence of Their Half-Lives on Therapeutic Activity

Cited by 33 publications

References 33 publications

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

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

Purification and Characterization of a Novel Subtype A3 Botulinum Neurotoxin

Characterization of Botulinum Neurotoxin A Subtypes 1 Through 5 by Investigation of Activities in Mice, in Neuronal Cell Cultures, and In Vitro

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