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Fhb, a novel factor H-binding surface protein, contributes to the antiphagocytic ability and virulence of

Yaya Pian1, Shuzhen Gan, Shujie Wang

  • 1State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China.

Infection and Immunity
|April 25, 2012
PubMed

Insights

A novel surface protein, Fhb (factor H-binding protein), significantly enhances Streptococcus suis serotype 2 virulence. Fhb aids bacteria in evading immune defenses by binding human factor H, crucial for complement regulation.

Area of Science:

  • Microbiology
  • Immunology
  • Bacterial Pathogenesis

Background:

  • Streptococcus suis serotype 2 causes severe infections in piglets and humans.
  • Mechanisms of S. suis serotype 2 virulence are not fully understood.
  • Surface proteins are critical for bacterial virulence and host interactions.

Purpose of the Study:

  • Identify novel surface proteins contributing to S. suis serotype 2 virulence.
  • Investigate the role of a newly identified protein in bacterial pathogenesis and host immune evasion.

Main Methods:

  • Identification and characterization of a novel surface protein, designated Fhb.
  • Analysis of fhb gene distribution and protein structure (proline-rich repeats, XPZ domains).
  • Assessment of fhb-deficient mutants in bactericidal assays and evaluation of Fhb's interaction with human factor H (hFH).

Main Results:

  • A novel surface protein, Fhb, was identified and significantly contributed to S. suis serotype 2 virulence in a piglet model.
  • Fhb exhibits strong binding to human factor H (hFH) and possesses structural similarities to IgA-binding proteins.
  • Fhb-deficient mutants showed reduced resistance to phagocytosis, indicating impaired innate immune evasion.
  • Fhb plays a role in complement-mediated immunity through interaction with hFH.

Conclusions:

  • Fhb is a crucial surface protein for Streptococcus suis serotype 2 virulence.
  • Fhb facilitates immune evasion by interacting with the host complement regulatory factor hFH.
  • Understanding Fhb's function provides insights into S. suis pathogenesis and potential therapeutic targets.

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