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Limulus amebocyte lysate reaction with streptococcal pyrogenic exotoxin
Infection and Immunity
|November 1, 1976
Summary
Group A streptococci pyrogenic exotoxins can trigger limulus amebocyte lysate coagulation. However, these bacterial toxins are significantly less potent than gram-negative endotoxins in this assay.
Area of Science:
- Microbiology
- Immunology
- Biochemistry
Background:
- Group A Streptococcus (GAS) produces pyrogenic exotoxins.
- Pyrogenic exotoxins are known virulence factors.
Purpose of the Study:
- To investigate the ability of GAS pyrogenic exotoxins to activate the limulus amebocyte lysate (LAL) assay.
- To compare the LAL coagulant activity of GAS exotoxins with that of gram-negative bacterial endotoxins.
Main Methods:
- Purification of three immunologically distinct pyrogenic exotoxins from group A streptococci.
- Assay of exotoxin activity using the limulus amebocyte lysate (LAL) coagulation test.
- Comparison of LAL coagulant activity with purified gram-negative bacterial endotoxin.
Main Results:
- Three distinct group A streptococcal pyrogenic exotoxins demonstrated the ability to cause coagulation of limulus amebocyte lysate.
- The coagulant activity of these streptococcal exotoxins was found to be significantly lower, several thousand times less potent, than that of gram-negative endotoxin.
Conclusions:
- Group A streptococcal pyrogenic exotoxins possess endotoxin-like activity in the LAL assay.
- The LAL assay may not be the most sensitive method for detecting certain bacterial toxins, as streptococcal exotoxins show weak activity compared to endotoxins.