Clostridium perfringens epsilon toxin mutant Y30A-Y196A as a recombinant vaccine candidate against enterotoxemia

Monika Bokori-Brown,Charlotte A Hall,Charlotte Vance,Sérgio P Fernandes Da Costa,Christos G Savva,Claire E Naylor,Ambrose R Cole,Ajit K Basak,David S Moss,Richard W Titball

doi:10.1016/j.vaccine.2014.03.079

Monika Bokori-Brown, Charlotte A Hall + Show 8 more

Open Access

https://doi.org/10.1016/j.vaccine.2014.03.079

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Journal: Vaccine	Publication Date: Apr 5, 2014
Citations: 44	License type: cc-by

Affiliation: University of Exeter, Birkbeck, University of London

Abstract

Epsilon toxin (Etx) is a β-pore-forming toxin produced by Clostridium perfringens toxinotypes B and D and plays a key role in the pathogenesis of enterotoxemia, a severe, often fatal disease of ruminants that causes significant economic losses to the farming industry worldwide. This study aimed to determine the potential of a site-directed mutant of Etx (Y30A-Y196A) to be exploited as a recombinant vaccine against enterotoxemia. Replacement of Y30 and Y196 with alanine generated a stable variant of Etx with significantly reduced cell binding and cytotoxic activities in MDCK.2 cells relative to wild type toxin (>430-fold increase in CT50) and Y30A-Y196A was inactive in mice after intraperitoneal administration of trypsin activated toxin at 1000× the expected LD50 dose of trypsin activated wild type toxin. Moreover, polyclonal antibody raised in rabbits against Y30A-Y196A provided protection against wild type toxin in an in vitro neutralisation assay. These data suggest that Y30A-Y196A mutant could form the basis of an improved recombinant vaccine against enterotoxemia.

Highlights

Clostridium perfringens is a Gram positive, anaerobe, spore forming bacterium that is classified into five toxinotypes based on production of the four typing toxins (␣, ␤, ␧, and ␫-toxins) [1]
In an attempt to identify an Epsilon toxin (Etx) variant with markedly reduced toxicity relative to wild type toxin that could be considered as a recombinant vaccine candidate, we combined mutations Y30A and Y196A, generating the double tyrosine mutant, termed Y30AY196A (Fig. 1A)
This study was conducted to determine the potential of the site-directed Etx mutant Y30A-Y196A to be exploited as a recombinant vaccine against enterotoxemia

Summary

Introduction

Clostridium perfringens is a Gram positive, anaerobe, spore forming bacterium that is classified into five toxinotypes based on production of the four typing toxins (␣-, ␤-, ␧-, and ␫-toxins) [1]. Epsilon toxin (Etx), a ␤-pore-forming toxin, is produced by C. perfringens strains that belong to toxinotypes B and D and plays a key role in the pathogenesis of enterotoxemia, a severe gastrointestinal disease of ruminants that causes severe economic losses to farmers worldwide. C. perfringens toxinotype B is the etiologic agent of dysentery in newborn lambs and haemorrhagic enteritis and enterotoxemia in goats, calves and foals [2,3]. C. perfringens toxinotype D affects mainly sheep and lambs and causes infections in goats and calves [2,3]. While infection of the central nervous system results in neurological disorders, the fatal effects on the organs often lead to sudden death [6,7]

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