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An analytical procedure, using gas-liquid chromatography, was developed for the identification of the per(trimethylsilyl) ethers of the constituent monosaccharides obtained from the capsular polysaccharides of Clostridium perfringens Hobbs 5, Hobbs 9, Hobbs 10, and NCTC 10578. Qualitative and quantitative differences between the major polysaccharide components enabled the differentiation of the four strains of C. perfringens investigated.

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.

The properties of the immunochemically distinct substances isolated from four strains of Clostridium perfringens, mucoid variants of Hobbs 1, 5, 9, and 10, were shown to be compatible with the hypothesis that polysaccharides are generally responsible for the "type-specificity" of these organisms. The presence of "group-specific" substance was demonstrated by the cross-reaction of recent preparations of Hobbs 5 antisera with the isolated polysaccharides. The cross-reactions were not observed with specific antisera of the other strains studied and were independent of the "type-specific" phenomenon.