Chemical and Immunological Studies of the Pneumococcus

Summary and Conclusions By the use of ultrafiltration and repeated fractional alcoholic precipitations in the cold in the presence of sodium acetate, highly purified preparations of the type specific substances have been obtained from broth-culture filtrates of pneumococci of types I through XXXII. Comparison of the nitrogen-, phosphorus-, and acetyl-content and of the optical rotations and relative viscosities of such materials with previously reported data indicates a similar degree of purification. Types I, IV, V, XII, and XXV contained the largest amounts of nitrogen, about 5 per cent. Ten other type preparations probably represented nitrogen-free carbohydrates. Type I alone had an appreciable amount of amino nitrogen, 2 per cent, as noted by other workers (5). Significant amounts of phosphorus were found in some of the preparations, as much as 6 per cent in types XXVIII and XXXII. The acetyl-content was negligible in types III and VIII, but in other types it varied, reaching 15 and 16 per cent in types IV and XI. The optical rotation was greatest for type I and almost negligible for type XXIII preparations. Twenty-five of the type specific carbohydrates were dextrorotatory and seven were levorotatory. The type-III solution had the highest relative viscosity and type VIII the next. Nine of the preparations gave qualitative tests for uronic acids and 20 for amino sugars. Before hydrolysis only type V showed reducing properties which persisted under mild conditions. After hydrolysis all of the preparations reduced Fehling's solution. Ammonium sulfate and basic lead acetate were the most generally effective of all the precipitants examined. In the properties studied, the preparations of the specific carbohydrates of types VIa and VIb (XXVI) could not be differentiated; but types XV and XXX were slightly different. All of the preparations precipitated homologous immune sera in dilutions as high as 1:4,096,000 or 1:8,192,000.