Development of vaccines for prevention of botulism

Abstract

-Botulism is a potentially lethal disease caused by one of seven homologous neurotoxic proteins usually produced by the bacterium, Clostridium botulinum. This neuromuscular disorder occurs through an exquisite series of molecular events, ultimately ending with the arrest of acetylcholine release and hence, flaccid paralysis. The development of vaccines that protect against botulism dates back to the 1940s. Currently, a pentavalent vaccine that protects against BoNT serotypes A-E and a separate monovalent vaccine that protects against BoNT serotype F are available as Investigational New Drugs. However, due to the numerous shortcomings associated with the toxoid vaccines, several groups have efforts towards developing next-generation vaccines. Identifying a synthetic peptide that harbors a neutralizing epitope is one approach to a BoNT vaccine, while another employs the use of a Venezuelan equine encephalitis virus replicon vector to produce protective antigens in vivo against BoNT. The strategy used in our laboratory is to design synthetic genes encoding non-toxic, carboxy-terminal fragments of the C. botulinum neurotoxins (rBoNT(H C )). The gene products are expressed in the yeast, Pichia pastoris, and purified to greater than 98% with yields typically ranging from 200-500 mg per kg of wet cells. Protective immunity to the purified products against high-level challenges of neurotoxin is elicited in mice and in non-human primates. A pre-Investigational New Drug meeting was held with the Food and Drug Administration, and the next milestone for the vaccine candidates will be clinical trials. © 2000 Société française de biochimie et biologie moléculaire / Éditions scientifiques et médicales Elsevier SAS botulinum neurotoxin / vaccine / C-fragment / purification / efficacy

An in vitro and in vivo disconnect uncovered through high-throughput identification of botulinum neurotoxin A antagonists

“…However, the availability of the human-derived immunoglobulins from immunized personnel is extremely limited. The most effective immunotherapy for protection against BoNTs relies on vaccination with pentavalent toxoid species, although supplies are reserved for high-risk individuals (9). Alternate countermeasures are limited to the passive administration of antibodies, which are expensive to produce in large enough quantities necessary to combat a bioterrorism attack, are currently of equine origin that can cause serious side effects, and have only a very short window of application.…”

Potent neutralization of botulinum neurotoxin by recombinant oligoclonal antibody

“…No specific small-molecule drugs exist for prevention or treatment of botulism, but an investigational pentavalent toxoid is available from the CDC (14) and a recombinant vaccine is under development (15). Regardless, mass civilian or military vaccination is unlikely because of the rarity of disease or exposure and the fact that vaccination would prevent subsequent medicinal use of BoNT.…”

Production and purification of a chimeric monoclonal antibody against botulinum neurotoxin serotype A

“…Currently, there are no small molecule drugs available to prevent botulism, although a pentavalent toxoid is available from the CDC. In addition to the pentavalent toxoid a recombinant vaccine is being developed [7] and [8]. Regardless of the availability of a recombinant vaccine, mass vaccination is unlikely due to the rarity of exposure and the fact the vaccination would prevent medical uses of BoNT.…”