Chemical and Immunological Studies of the Pneumococcus

Summary

1. 1. From the bacterial cells of types I, II, III and of an atypical variant of type I pneumococci, substances of carbohydrate nature have been prepared.

2. 2. They all contained phosphorus and nitrogen.

3. 3. They differed in their precipitative activity. The fractions from the virulent organisms of the three types reacted in high dilution with the homologous antisera only, while that from the atypical type I pneumococci reacted with type I antiserum in a very low dilution and with types II and III in high dilution.

4. 4. They gave rise to skin reactions in immunized but not in normal rabbits. The response was not highly specific.

5. 5. They induced purpura in mice. This activity of the type I cellular carbohydrate, which further distinguished it from the soluble specific substance, was not destroyed when the cellular substance was heated in n/100 sodium hydroxide or hydrochloric acid, at 100°C. for thirty minutes or was autoclaved in n/100 sodium hydroxide, at 120°C. for twenty minutes. It was inhibited by type I antipneumococcus rabbit serum and intensified by immune horse serum.

6. 6. The type I material could be separated by acid precipitation into two fractions which differed in their precipitative activity and in their ability to induce purpura in mice.

7. 7. The type I cellular carbohydrate precipitated from two to three times as much nitrogen from immune serum as did the soluble specific substance.

8. 8. When injected through the trachea into the rabbit lung, the type I cellular carbohydrate gave rise to a marked diffuse inflammatory reaction.

9. 9. The cellular carbohydrates of all three types induced specific anaphylactic shock in sensitized guinea pigs. The cellular carbohydrate from the type I attenuated strain did not induce this phenomenon in guinea pigs sensitized with any one of the three types of antisera.