Studies in immuno-chemistry

Abstract

Bacterial suspension was extracted at 100[degree]C with dilute acetic acid at pH 4. The polysaccharide was purified by precipitation as a basic lead complex, and non-specific poly-saccharides derived from the medium were removed by fractional precipitation with acetic acid. The specific polysaccharides from 2 strains of Shiga bacillus were identical in all respects. 1000 Roux bottles of culture yield 1-2 gms. of pure specific polysaccharide. The material is strongly dextrorotatory ([alpha])D + 98[degree]: it contains 1.6% N2 in the form of acetylated amino groups, yields 97% reducing sugars on acid hydrolysis, and accounts completely for the serological specificity of the organism.