Binding studies on isolated porcine small intestinal mucosa and in vitro toxicity studies reveal lack of effect of C. perfringens beta-toxin on the porcine intestinal epithelium.

Simone Roos,Christina Nathues,Nadine Regenscheit,Ahmet Candi,Horst Posthaus,Filip van Immerseel,Marianne Wyder

doi:10.3390/toxins7041235

Simone Roos, Christina Nathues + Show 5 more

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https://doi.org/10.3390/toxins7041235

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Journal: Toxins	Publication Date: Apr 9, 2015
Citations: 44	License type: CC BY 4.0

Affiliation: University of Bern, Ghent University

Abstract

Beta-toxin (CPB) is the essential virulence factor of C. perfringens type C causing necrotizing enteritis (NE) in different hosts. Using a pig infection model, we showed that CPB targets small intestinal endothelial cells. Its effect on the porcine intestinal epithelium, however, could not be adequately investigated by this approach. Using porcine neonatal jejunal explants and cryosections, we performed in situ binding studies with CPB. We confirmed binding of CPB to endothelial but could not detect binding to epithelial cells. In contrast, the intact epithelial layer inhibited CPB penetration into deeper intestinal layers. CPB failed to induce cytopathic effects in cultured polarized porcine intestinal epithelial cells (IPEC-J2) and primary jejunal epithelial cells. C. perfringens type C culture supernatants were toxic for cell cultures. This, however, was not inhibited by CPB neutralization. Our results show that, in the porcine small intestine, CPB primarily targets endothelial cells and does not bind to epithelial cells. An intact intestinal epithelial layer prevents CPB diffusion into underlying tissue and CPB alone does not cause direct damage to intestinal epithelial cells. Additional factors might be involved in the early epithelial damage which is needed for CPB diffusion towards its endothelial targets in the small intestine.

Highlights

The anaerobic, Gram-positive, spore-forming bacterium C. perfringens causes different diseases in humans and animals, such as septicemia, myonecrosis, enterotoxemia, food poisoning and enteritis [1].Classification into five types is based on the production of four major toxins: Alpha- (CPA), beta- (CPB), epsilon (ETX)- and iota-toxin (ITX) [2]
Using porcine small intestinal mucosal explants and cryosections incubated with C. perfringens type C culture supernatants, we confirmed that CPB preferentially binds to endothelial cells in the porcine small intestinal mucosa but not to epithelial cells
We confirmed that in the porcine small intestine, CPB preferentially binds to endothelial cells and that it does not appear to bind to small intestinal epithelial cells nor does it have a direct toxic effect on the porcine small intestinal epithelium

Summary

Introduction

The anaerobic, Gram-positive, spore-forming bacterium C. perfringens causes different diseases in humans and animals, such as septicemia, myonecrosis, enterotoxemia, food poisoning and enteritis [1]. Classification into five types is based on the production of four major toxins: Alpha- (CPA), beta- (CPB), epsilon (ETX)- and iota-toxin (ITX) [2]. C. perfringens type C produces CPA and CPB; additional toxins, such as beta-2 toxin, enterotoxin, perfringolysin and TpeL can be secreted [3,4]. C. perfringens type C causes necrotizing enteritis (NE) in newborn animals and in humans [1]. The exact role of different toxins in the pathogenesis of the disease is not known yet. Experimental studies using genetic approaches and animal models of disease clearly demonstrated that CPB is the essential virulence factor of type C strains [6]

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