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Characterization of recombinant Streptococcus mitis-derived human platelet aggregation factor

Hisashi Ohkuni1, Hideaki Nagamune, Nana Ozaki

  • 1Health Science Research Institute East Japan Co. Ltd, Kounosu, Saitama, Japan. h-okuni@nms.ac.jp

APMIS : Acta Pathologica, Microbiologica, Et Immunologica Scandinavica
|December 14, 2011
PubMed

Insights

Recombinant Streptococcus mitis-derived human platelet aggregation factor (rSm-hPAF) exhibits potent hemolytic and platelet aggregation activities. This protein, similar to other cholesterol-dependent cytolysins, offers insights into bacterial virulence factors.

Area of Science:

  • Microbiology
  • Immunology
  • Biochemistry

Background:

  • Streptococcus mitis-derived human platelet aggregation factor (Sm-hPAF) was previously purified.
  • Sm-hPAF was isolated from S. mitis strain Nm-65, found on the tooth surface of a Kawasaki disease patient.

Purpose of the Study:

  • To produce recombinant Sm-hPAF (rSm-hPAF) in Escherichia coli.
  • To determine if rSm-hPAF retains its platelet aggregation activity.

Main Methods:

  • Recombinant protein production in E. coli.
  • Hemolytic activity assays on mammalian erythrocytes.
  • Platelet aggregation assays.
  • Morphological confirmation using light and electron microscopy.

Main Results:

  • Recombinant Sm-hPAF (rSm-hPAF) demonstrated potent hemolytic activity against human erythrocytes.
  • rSm-hPAF exhibited significant human platelet aggregation activity.
  • The amino-terminal domain of rSm-hPAF shares homology with pneumococcal fucolectin-related protein.
  • Other cholesterol-dependent cytolysins, suilysin (SLY) and pneumolysin (PLY), also showed human platelet aggregation activity.

Conclusions:

  • Recombinant Sm-hPAF conserves its platelet aggregation and hemolytic activities.
  • rSm-hPAF shares characteristics with cholesterol-dependent cytolysins, suggesting a role in bacterial pathogenesis.
  • The platelet aggregation activity of Sm-hPAF, SLY, and PLY provides new avenues for research into bacterial-host interactions.

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