The reaction between type II pneumococcus antiserum and a glucuronide azo-protein

Abstract

An amino derivative of the natural glucuronide, euxanthic acid, was prepd. and coupled by the azo-link to proteins. These azo-proteins gave precipitates with Type II pneumococcus antiserum, which were inhibited by glucuronides. The effect of varying azo-protein/serum ratio on the amount and composition of the precipitate was similar to the effect of varying polysaccharide/serum ratio on the precipitate formed when the specific polysaccharide is added to the serum. Attempts to immunize rabbits and mice with amino-euxanthic acid azo-protein were not successful. Chemical estimations and animal protection expts. indicated that the material precipitated by the azo-protein from the serum was part of the antibody to Type II pneumococcus. These results support the view that at any rate part of the specificity of Type II serum for the type polysaccharide is due to glucuronic acid or some closely similar grouping.