Development and Application of New Mouse Models To Study the Pathogenesis of Clostridium perfringens Type C Enterotoxemias

Abstract

Clostridium perfringens type C isolates cause enterotoxemias and enteritis in humans and livestock. While the major disease signs and lesions of type C disease are usually attributed to beta toxin (CPB), these bacteria typically produce several different lethal toxins. Since understanding of disease pathogenesis and development of improved vaccines is hindered by the lack of small animal models mimicking the lethality caused by type C isolates, in this study we developed two mouse models of C. perfringens type C-induced lethality. When inoculated into BALB/c mice by intragastric gavage, 7 of 14 type C isolates were lethal, whereas when inoculated intraduodenally, these strains were all lethal in these mice. Clinical signs in intragastrically and intraduodenally challenged mice were similar and included respiratory distress, abdominal distension, and neurological alterations. At necropsy, the small, and occasionally the large, intestine was dilated and gas filled in most mice developing a clinical response. Histological changes in the gut were relatively mild, consisting of attenuation of the mucosa with villus blunting. Inactivation of the CPB-encoding gene rendered the highly virulent type C strain CN3685 avirulent in the intragastric model and nearly nonlethal in the intraduodenal model. In contrast, inactivation of the genes encoding alpha toxin and perfringolysin O only slightly decreased the lethality of CN3685. Mice could be protected against lethality by intravenous passive immunization with a CPB antibody prior to intragastric challenge. This study proves that CPB is a major contributor to the systemic effects of type C infections and provides new mouse models for investigating the pathogenesis of type C-induced lethality.

Endothelial Binding of Beta Toxin to Small Intestinal Mucosal Endothelial Cells in Early Stages of Experimentally Induced Clostridium Perfringens Type C Enteritis in Pigs

“…The essential role of CPB in C. perfringens type C enteritis has recently been demonstrated by a combination of reverse genetics and small laboratory animal infection models. 5,9 These models are well suited to determine essential virulence factors and mechanisms of C. perfringens type C enteritis. However, susceptibility of target cells to toxins might differ among host species, and infectious models based on naturally affected species represent valuable additions to existing models.…”

“…1,6,8 CPB has been identified as an essential virulence factor of type C strains using 2 small laboratory animal models. 5,9 The exact mechanism of toxicity and the natural target cells of CPB are, however, not yet unequivocally defined. It was hypothesized that CPB directly causes epithelial necrosis; however, scientific proof for a direct toxic effect of the toxin on epithelial cells is lacking.…”

“…2,3 Experimental infections in rabbits and mice indicated that species differences in the reaction to this enteric infection exist. 5,9 The goal of this limited study was (1) to modify an experimental porcine intestinal loop infection model to reproduce early lesions of NE and (2) to determine CPB binding to potential target cells in the small intestine during early stages of NE in a naturally affected animal species. The porcine C. perfringens type C strain JF 3721 2 , the type C reference strain NCTC 3180, and as a control, the porcine C. perfringens type A isolate JF 3693 2 were used.…”

Clostridium perfringenstype C isolates rapidly upregulate their toxin production upon contact with host cells

“…Therefore, the CN3685 toxin null mutants were also recently tested in a mouse intraduodenal challenge model that, in the presence of TI, reproduces the lethal aspects of type C enterotoxemias. 10 In this assay, wild-type CN3685 was nearly 100% lethal for mice, but an isogenic cpb null mutant was strongly attenuated for lethality. In contrast, an isogenic CN3685 double mutant unable to produce α-toxin or PFO showed only a small decrease in lethality.…”

Isolation, Specification, Molecular Biology Assessment and Vaccine Development of Clostridium in Iran: A Review

“…It is known to aid in the lysis of endothelial cells by forming pores in the cell membrane (26). This function is necessary both for necrotizing enteritis and lethal enterotoxaemia caused by type C isolates (27,28). A 17-protein exotoxin is produced by this bacterium which four of them are major (alpha, beta, epsilon and Utah), and the others (sigma, theta, kappa, lambda, mu, nu, neuraminidase and enterotoxin) are minor toxins (29).…”