Capsular polysaccharide of Clostridium perfringens Hobbs 10

A capsular polysaccharide was isolated from a strain of Clostridium perfringens Hobbs 10 type A by cold-water extraction of whole, heavily encapsulated cells. The water-soluble polymer was isolated by alcohol precipitation and purified by treatment with chloroform-butanol, cetytrimethylammonium bromide, and column gel permeation chromatography by using Bio-Gel A-5m agarose. The formation of a single precipitin line, when the isolated polysaccharide was reacted with its homologous antisera by double diffusion in gel, was considered a criterion of immunochemical purity. The purified polymer appeared as a single peak when eluted from diethylaminoethyl-Sephadex with a linear gradient of NaCl. The polysaccharide was composed of glucose, galactose, galactosamine, and iduronic acid in a molar ratio of 4.1:5.1.7:1, respectively. These constituents accounted for 83% of the dry weight. The polysaccharide appeared to have a molecular weight of 40,000 and exhibited aggregation up to 120,000. A trace of peptide material could not be removed during purification.