Chemical and Immunological Studies of the Pneumococcus

[摘要] Preparations of the soluble specific substances of fifteen new types, subtypes, and untyped related strains of pneumococci were obtained by methods previously described—ultrafiltration followed by repeated fractional alcoholic precipitation in the cold. Type 7A alone failed to yield a highly purified product; from it only a colored product with a positive ninhydrin reaction was obtained.Quantitative data such as percentage of nitrogen, phosphorus, acetyl group, ash, and reducing sugars, optical rotation and relative viscosity, and qualitative tests for uronic acids and amino sugars were not adequate to distinguish between strains that are closely related serologically. Although quantitative differences were found, particularly in the percentages of nitrogen, acetyl group, and reducing sugar, and in the degree of optical rotation, they were often not greater than may occur in different preparations from the same strain. In general, specific carbohydrates of related types of pneumococci had similar properties. Differences were noted, however, in the precipitability of the soluble specific substances from aqueous solution by such salts as ammonium sulfate, basic lead acetate, and uranyl nitrate.Carbohydrate preparations from pneumococci of types 18, 18A, and of strain no. 38123, which is related to type 18, were distinctive in that after hydrolysis type 18 gave a negative test for amino sugar, 18A gave a weakly positive, and no. 38123, a strongly positive test.The type-26 soluble specific substance was unusual in that it reduced Fehling's solution before hydrolysis.Preparations from all the strains precipitated homologous immune sera in dilutions of 1:4,096,000 or 1:8,192,000.

[学科分类] 生物科学（综合）