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Guanidine extraction of streptococcal M protein
Infection and Immunity
|September 1, 1975
Summary
Researchers developed a new method to extract M protein from streptococcal cell walls using guanidine hydrochloride. The purified 0.3 M phosphate fraction yielded electrophoretically homogeneous M protein that produced bactericidal antibodies in rabbits.
Area of Science:
- Microbiology
- Immunology
- Biochemistry
Background:
- Streptococcal M protein is a key virulence factor.
- Efficient extraction and purification of M protein are crucial for immunological studies.
Purpose of the Study:
- To develop and characterize a novel method for extracting and purifying streptococcal M protein.
- To assess the immunogenicity of the purified M protein fractions.
Main Methods:
- Extraction of M protein using guanidine hydrochloride.
- Purification via ammonium sulfate fractionation, pH 5 fractionation, and hydroxyapatite column chromatography.
- Analysis of eluted fractions using SDS-PAGE and immunological assays.
Main Results:
- Hydroxyapatite chromatography yielded three protein peaks eluted with 0.01, 0.1, and 0.3 M phosphate buffers.
- Fractions eluted at 0.1 and 0.3 M phosphate contained M protein antigens.
- The 0.3 M phosphate fraction was electrophoretically homogeneous and elicited bactericidal antibodies in rabbits.
Conclusions:
- The developed method successfully extracts and purifies immunogenic streptococcal M protein.
- The electrophoretically homogeneous M protein fraction is capable of inducing bactericidal antibodies, suggesting its potential for vaccine development.