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Extracellular esterases of group A streptococci
Infection and Immunity
|April 1, 1973
Summary
Researchers developed methods to quantify extracellular esterases (STE) from group A streptococci. Horse serum and specific antibodies were found to activate and protect these enzymes from inhibition by cupric acetate.
Area of Science:
- Microbiology
- Enzymology
- Immunology
Background:
- Extracellular esterases (STE) from group A streptococci play roles in bacterial pathogenesis.
- Quantitative assessment and characterization of STE activity are crucial for understanding their function.
- Factors influencing STE activity, such as metal ions and biological fluids, require investigation.
Purpose of the Study:
- To develop methods for the quantitative preparation and estimation of extracellular esterases (STE) from group A streptococci.
- To investigate the effects of cupric acetate, animal sera, and rabbit antisera on STE activity.
- To identify and characterize factors that activate and protect STE from inhibition.
Main Methods:
- Preparation of two types of STE (STE I and STE II) from specific Streptococcus pyogenes strains.
- Assay of STE activity in the presence of varying concentrations of cupric acetate.
- Testing the effects of sera from various animals and rabbit antisera against STE I and II on enzyme activity.
- Extraction and characterization of horse serum-activating factor (HAF).
Main Results:
- Cupric acetate inhibited STE activity in a dose-dependent manner.
- Animal sera, particularly horse serum, stimulated STE activity and protected against cupric acetate inhibition.
- Horse serum-activating factor (HAF) was isolated and demonstrated to activate and protect STE.
- Rabbit antisera to STE I and II showed specific activation and protection effects, differing from HAF.
- Homologous antiserum provided stronger activation and protection than heterologous antiserum or normal rabbit serum.
Conclusions:
- Quantitative methods for preparing and assaying group A streptococcal extracellular esterases were established.
- Horse serum contains a factor (HAF) that activates and protects STE, while specific antibodies offer similar but immunologically distinct effects.
- These findings provide a basis for differentiating STE antibodies and assessing enzyme potency under various conditions.