Immunity in Human Beings to the Pneumococcus

Abstract

In the fall of 1930, I began a study of the products of several bacteria in the search for hitherto unknown exotoxins which could be identified as the pathogenic agents of the respective microorganisms. This paper is a summary of the findings with various culture filtrates of the pneumococcus.

In this work I have enjoyed the cooperation of Dr. Henry W. Straus and of Dr. Norman Plummer. We shall make a detailed report of the experiments, some of which are still in progress.

The existence of a pneumococcus toxin had been suspected and A. B. Wadsworth had recommended the injection of whole cultures rather than the collected bacterial bodies in the immunization of horses.

In view of the consistent failures to demonstrate the toxin in animal experiments it was decided to test the filtrates upon young and presumably susceptible children by subcutaneous injection; the criteria of toxic action were to be a local effect and a rise in temperature.

The experiments were begun with a freshly isolated culture of type II pneumococcus obtained from Dr. Plummer.

The first filtrates produced temperatures ranging from 101°F. to 104°F. in subcutaneous doses of 2.0 cc. to 4.0 cc. or of 0.5 cc. to 1.0 cc. of the filtrate concentrated by acetone precipitation according to the method of Wadsworth and Quigley. 1 There was tenderness and swelling at the site of injection.

The later experiments were carried out with an unconcentrated filtrate from a stock type I culture which produced temperatures of 101°F. and upward in a quantity of 0.5 cc.

Immunity to the fever-producing substance was established in some children after a single pyrogenic dose or 2, and in a series of 21 children of about 5 years of age, immunity was established in 14 within 2 weeks after a second injection.