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Updated: Aug 4, 2026

Measuring the 50% Haemolytic Complement (CH50) Activity of Serum
08:26

Measuring the 50% Haemolytic Complement (CH50) Activity of Serum

Published on: March 29, 2010

Similarities between complement-mediated and streptolysin S-mediated hemolysis

A Carr1, D D Sledjeski, A Podbielski

  • 1Department of Microbiology & Immunology, Medical College of Ohio, Toledo, Ohio 43614-5806, USA.

The Journal of Biological Chemistry
|September 8, 2001
PubMed

Insights

Streptococcus pyogenes streptolysin S (SLS) hemolysin activity depends on temperature and concentration. Its mechanism involves distinct intermediates, similar to complement-mediated hemolysis, leading to erythrocyte lysis.

Area of Science:

  • Microbiology
  • Immunology
  • Biochemistry

Background:

  • Streptococcus pyogenes produces streptolysin S (SLS), an oxygen-stable hemolysin.
  • SLS is implicated in the pathogenesis of S. pyogenes infections.
  • The pel/sagA gene product is involved in encoding SLS.

Purpose of the Study:

  • To investigate the mechanism of streptolysin S (SLS)-mediated hemolysis.
  • To characterize the temperature and concentration dependence of SLS activity.
  • To identify and compare intermediates in the SLS hemolytic pathway with complement-mediated hemolysis.

Main Methods:

  • Antibody inhibition assays using synthetic peptides from Pel/SagA.
  • Analysis of hemolytic reactions under varying temperature and concentration conditions.
  • Distinguishing intermediates in the erythrocyte lysis process.

Main Results:

  • Antibodies against a C-terminal peptide of Pel/SagA inhibited SLS hemolysis.
  • SLS-mediated hemolysis is temperature- and concentration-dependent, following a one-hit mechanism.
  • Distinct intermediates were identified, including temperature-dependent binding and papain-sensitive stages, prior to pore formation and lysis.

Conclusions:

  • SLS-mediated hemolysis involves specific binding and intermediate stages before irreversible cell lysis.
  • The identified intermediates share similarities with those observed in complement-mediated hemolysis.
  • Understanding these mechanisms provides insights into S. pyogenes pathogenesis and potential therapeutic targets.

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