Clostridium perfringens invasiveness is enhanced by effects of theta toxin upon PMNL structure and function: The role of leukocytotoxicity and expression of CD11/CD18 adherence glycoprotein

Abstract

Clostridium perfringens infections are characterized by the lack of an inflammatory response at the site of infection and rapidly progressive margins of tissue necrosis. Studies presented here investigated the role of theta toxin from C. perfringens in the pathophysiology of these events. Mice passively immunized with neutralizing monoclonal antibody against theta toxin and challenged with an LD100 of log phase C. perfringens had significantly less mortality than untreated controls. Intramuscular injection of killed, washed C. perfringens in mice induced a massive time-dependent influx of polymorphonuclear leukocytes (PMNL) into tissue; injection of either viable, washed C. perfringens or killed organisms plus theta toxin dramatically attenuated PMNL influx although PMNL accumulated in adjacent vessels. The anti-inflammatory effects could not be attributed to an absence of chemoattractants since C. perfringens proteins had chemotactic factor activity, and killed bacilli generated serum-derived chemotactic factors. Scanning and transmission electron microscopy demonstrated the dramatic leukocidal effects of high doses of theta toxin on PMNL. In contrast, sublethal concentrations of theta toxin primed PMNL chemiluminescence, disrupted PMNL cytoskeletal actin polymerization/disassembly, and stimulated functional upregulation of CD11b/CD18 adherence glycoprotein. In summary, these results demonstrate that theta toxin is an important virulence factor in C. perfringens infection. In a concentration-dependent fashion, theta toxin contributes to the pathogenesis of clostridial gangrene by direct destruction of host inflammatory cells and tissues, and by promoting dysregulated PMNL/endothelial cell adhesive interactions.

Biology and Pathogenesis of Thrombosis and Procoagulant Activity in Invasive Infections Caused by Group A Streptococci andClostridium perfringens

“…Sublytic concentrations of SLO and a related toxin, perfringolysin O, from C. perfringens each stimulate the functional upregulation of PMNL CD11b/CD18 (18,22) and prime neutrophils for enhanced respiratory burst activity (18). Thus, it is likely that these thiol-activated toxins may indirectly contribute to coagulation by stimulating CD11b/CD18-dependent activation of factor X (69) (see above section on platelet-leukocyte complexes) and by stimulating premature degranulation of hyperadherent PMNL.…”

Clostridium perfringens phospholipase C-induced platelet/leukocyte interactions impede neutrophil diapedesis

“…Neutrophils were isolated by differential density-gradient centrifugation as previously described (Bryant et al, 1993 For each test, fluorescently labelled isolated platelets and neutrophils were combined in a total volume of 1 ml (platelet : neutrophil ratio, 50 : 1), and the solution reconstituted to contain fibrinogen (100 mg ml…”

Effects of Clostridium perfringens Alpha-Toxin (PLC) and Perfringolysin O (PFO) on Cytotoxicity to Macrophages, on Escape from the Phagosomes of Macrophages, and on Persistence of C. perfringens in Host Tissues

“…Purified PFO has been reported to be cytotoxic to PMNs in vitro (4,37,38). The cytotoxicity of PLC to leukocytes is less clear.…”