abstract |
A composition comprising a lipidated form of capsular polysaccharide A (PSA) from B. fragilis, and a method for its isolation and purification. Extracting a capsular complex from B. fragilis into an aqueous phase using a mixture of phenol and water at high temperature, and precipitating polysaccharide A (PSA) from the aqueous phase using ethanol Treating the precipitate with 2% acetic acid at elevated temperatures, (a) in the absence of surfactant, and / or (b) at a pH below about 9. [Selection figure] None |