Clostridial gas gangrene: Evidence that α and θ toxins differentially modulate the immune response and induce acute tissue necrosis

The rapid extension of necrosis and an absence of polymorphonuclear leukocytes (PMNL) at the site of infection are two hallmarks of Clostridium perfringens gas gangrene. While both α and θ toxins profoundly affect PMNL function and viability in vitro, their roles in muscle destruction and impairment of the inflammatory response in vivo have not been investigated. Comparative histopathologic examinations were performed on animals infected with either wild-type C. perfringens, or isogenic, toxin-deficient mutants of C. perfringens. Tissue destruction was modest in animals infected with the α toxin deficient mutant; destruction was more pronounced in tissues infected with the θ toxin-deficient mutant or the wild-type strain. α and θ toxins also displayed differing abilities to modulate the inflammatory response. Histopathologic studies in which recombinant toxins were injected together with killed, washed C. perfringens further substantiated these tissue- destructive and differential antiinflammatory effects.