Clostridium perfringens α-Toxin Impairs Innate Immunity via Inhibition of Neutrophil Differentiation

Sci Rep. 2016 Jun 16:6:28192. doi: 10.1038/srep28192.

Abstract

Although granulopoiesis is accelerated to suppress bacteria during infection, some bacteria can still cause life-threatening infections, but the mechanism behind this remains unclear. In this study, we found that mature neutrophils in bone marrow cells (BMCs) were decreased in C. perfringens-infected mice and also after injection of virulence factor α-toxin. C. perfringens infection interfered with the replenishment of mature neutrophils in the peripheral circulation and the accumulation of neutrophils at C. perfringens-infected sites in an α-toxin-dependent manner. Measurements of bacterial colony-forming units in C. perfringens-infected muscle revealed that α-toxin inhibited a reduction in the load of C. perfringens. In vitro treatment of isolated BMCs with α-toxin (phospholipase C) revealed that α-toxin directly decreased mature neutrophils. α-Toxin did not influence the viability of isolated mature neutrophils, while simultaneous treatment of BMCs with granulocyte colony-stimulating factor attenuated the reduction of mature neutrophils by α-toxin. Together, our results illustrate that impairment of the innate immune system by the inhibition of neutrophil differentiation is crucial for the pathogenesis of C. perfringens to promote disease to a life-threatening infection, which provides new insight to understand how pathogenic bacteria evade the host immune system.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bacillus subtilis / genetics
  • Bacillus subtilis / pathogenicity
  • Bacterial Toxins / genetics
  • Bacterial Toxins / toxicity*
  • Bone Marrow Cells / drug effects*
  • Calcium-Binding Proteins / genetics
  • Calcium-Binding Proteins / toxicity*
  • Cell Differentiation / drug effects
  • Cells, Cultured
  • Clostridium Infections / pathology
  • Clostridium perfringens / genetics
  • Clostridium perfringens / pathogenicity*
  • Granulocyte Colony-Stimulating Factor / pharmacology
  • Immunity, Innate / drug effects
  • Immunity, Innate / immunology*
  • Leukocyte Count
  • Mice
  • Mice, Inbred C57BL
  • Muscle, Skeletal / cytology
  • Neutrophils / immunology*
  • Type C Phospholipases / genetics
  • Type C Phospholipases / toxicity*
  • Virulence Factors / genetics
  • Virulence Factors / toxicity*

Substances

  • Bacterial Toxins
  • Calcium-Binding Proteins
  • Virulence Factors
  • Granulocyte Colony-Stimulating Factor
  • Type C Phospholipases
  • alpha toxin, Clostridium perfringens