The Control of the Dosage of Antiserum in the Treatment of Pneumococcal Pneumonia. I. a Study of the Mechanism of the Skin Reaction to Type Specific Polysaccharide.

In 1917 Dochez and Avery (1) isolated from cultures of actively growing pneumococci and from the blood and urine of patients suffering from pneumonia a soluble substance which possessed the property of precipitating homologous antibody. Finding that this "specific soluble substance" neutralized the protective action of antipneumococcal immune bodies, Cole (2), in the same year, advanced an important hypothesis. He suggested that antiserum administered therapeutically could not be expected to influence the course of pneumococcal pneumonia until an excess of antibody had been given over and above that needed to neutralize the specific soluble substance circulating in the patient's blood. The specific soluble substance is now known to be a complex polysaccharide derived from the capsule, specifically antigenic, and chemically unique for each type of pneumococcus. More recently it has been found in high concentration in pneumonic pulmonary exudates (3) and has been shown to nullify the opsonizing properties of homologous antibody in vitro (4), as well as neutralize its protective action in vivo. The importance of the hypothesis advanced by Cole lies in the fact that the quantity of polysaccharide to be neutralized in the blood of patients with pneumonia varies within extremely wide limits. The production of polysaccharide depends upon many factors, including the duration and extent of the infection, the rapidity with which the pneumococci are multiplying in the lung, invasion of the blood stream, and the polysaccharideproducing power of the particular type of pneumococcus causing the pneumonia.' These com-