The aggressin-like action of anaphylatoxin

In the course of experiments upon the repeated injection of anaphylatoxin into guinea-pigs the writers noticed a phenomenon which suggested to them that the anaphylatoxic substances may possibly possess properties similar to those described by Bail for his “aggressins.” In the earlier experiments the anaphylatoxins were prepared with typhoid bacilli by emulsifying one slant of the bacteria in 8 c.c. of fresh guinea pig complement and allowing the emulsion to remain in the incubator for 6 hours. At the end of this time centrifugation for one to two hours at high speed was used to throw down the bacteria.

Although the supernatant fluid after such centrifugation was clear, nevertheless it appeared in many cases that not all the bacteria were thrown down. Intraperitoneal injection of the anaphylatoxin occasionally resulted in the rapid death of the guinea-pigs with extensive proliferation of typhoid bacilli in the peritoneal exudate and presence of the organisms in the heart's blood.

Since the lethal dose of the typhoid culture employed varied between 1/10 and 1/50 of an agar slant (for guinea-pigs of about 200 grammes on intraperitoneal injection) and since the amounts of bacteria injected with 2 to 3 c.c. of an apparently clear anaphylatoxin could not have been anything like as much as the smallest lethal dose, special experiments were carried out to determine this point. An example of such experiments is the following: