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Staphylococcus sciuri exfoliative toxin C is a dimer that modulates macrophage functions

Haihua Li1, Xiaying Li, Ying Lu

  • 1State Key Laboratory of Agrobiotechnology, College of Veterinary Medicine, China Agricultural University, Beijing 100193, People's Republic of China.

Canadian Journal of Microbiology
|August 23, 2011
PubMed

Insights

Staphylococcus sciuri exfoliative toxin C (ExhC) inhibits macrophage phagocytosis and enhances inflammatory mediator production. This suggests ExhC plays a key role in the innate immune response to S. sciuri infections.

Area of Science:

  • Microbiology
  • Immunology
  • Toxicology

Background:

  • Staphylococcus sciuri is a pathogen causing human infections.
  • A strain of S. sciuri carrying exfoliative toxin C (ExhC) has been linked to severe skin pathology in piglets and potential zoonotic transmission.
  • The pathogenicity of S. sciuri, particularly the role of ExhC, remains poorly understood.

Purpose of the Study:

  • To investigate the pathogenicity of Staphylococcus sciuri exfoliative toxin C (ExhC).
  • To examine the effects of recombinant ExhC (rExhC) on macrophage functions in vitro and in vivo.
  • To elucidate the role of ExhC in the innate immune response to S. sciuri.

Main Methods:

  • Production and purification of recombinant ExhC protein with a histidine tag (rExhC-his).
  • Assessment of rExhC activity using newborn mice as a model.
  • Investigation of rExhC's impact on macrophage phagocytosis using RAW264.7 cell lines.
  • Measurement of proinflammatory mediator production (interleukin-6, interleukin-12, tumor necrosis factor α, nitric oxide) by murine peritoneal macrophages and RAW264.7 cells upon exposure to rExhC.

Main Results:

  • Both native S. sciuri ExhC and rExhC were found to exist as dimers.
  • rExhC significantly inhibited the phagocytic activity of RAW264.7 cells.
  • rExhC enhanced the production of key proinflammatory mediators, including IL-6, IL-12, TNF-α, and nitric oxide, in macrophages.

Conclusions:

  • Exfoliative toxin C (ExhC) from Staphylococcus sciuri exhibits immunomodulatory functions.
  • ExhC's ability to inhibit phagocytosis and stimulate inflammatory responses suggests a significant role in the pathogenesis of S. sciuri infections.
  • ExhC may be a crucial factor in how S. sciuri evades or manipulates the host innate immune system.

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