title: 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.
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.
authors: Department of Infectious Diseases and Pathobiology, Institute of Animal Pathology, Vetsuisse Faculty, University of Bern, Bern 3012, Switzerland. simone.roos@vetsuisse.unibe.ch.
authors: Simone
authors: S
authors: Roos
authors: Department of Infectious Diseases and Pathobiology, Institute of Animal Pathology, Vetsuisse Faculty, University of Bern, Bern 3012, Switzerland. marianne.wyder@vetsuisse.unibe.ch.
authors: Marianne
authors: M
authors: Wyder
authors: Department of Infectious Diseases and Pathobiology, Institute of Animal Pathology, Vetsuisse Faculty, University of Bern, Bern 3012, Switzerland. ahmet.candi@vetsuisse.unibe.ch.
authors: Ahmet
authors: A
authors: Candi
authors: Department of Infectious Diseases and Pathobiology, Institute of Animal Pathology, Vetsuisse Faculty, University of Bern, Bern 3012, Switzerland. nadine.regenscheit@vetsuisse.unibe.ch.
authors: Nadine
authors: N
authors: Regenscheit
authors: Veterinary Public Health Institute, Vetsuisse Faculty, University of Bern, Bern 3012, Switzerland. christina.nathues@vetsuisse.unibe.ch.
authors: Christina
authors: C
authors: Nathues
authors: Department of Pathology, Bacteriology and Avian Medicine, Ghent University, Ghent 9000, Belgium. filip.vanImmerseel@ugent.be.
authors: Filip
authors: F
authors: van Immerseel
authors: Department of Infectious Diseases and Pathobiology, Institute of Animal Pathology, Vetsuisse Faculty, University of Bern, Bern 3012, Switzerland. horst.posthaus@vetsuisse.unibe.ch.
authors: Horst
authors: H
authors: Posthaus
mesh_terms: D000818:Animals; D001427:Bacterial Toxins / Q000633:toxicity*; D002460:Cell Line; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000187:drug effects* / Q000473:pathology; D004847:Epithelial Cells / Q000166:cytology / Q000187:drug effects; D007413:Intestinal Mucosa / Q000166:cytology / Q000187:drug effects*; D007421:Intestine, Small; D013552:Swine
chemical_list: D001427:Bacterial Toxins; C031884:CPB protein, Clostridium perfringens