Fractionation and Immunological Properties of a DNA-rich Preparation from Brucella abortus.

Abstract

A DNA-rich preparation, obtained from Brucella abortus by extraction with 0.5% phenol, was fractionated by differential ultracentrifugation, and its immunological properties were studied. The antigens that precipitated antibodies from the sera of rabbits injected with the crude DNA preparation were concentrated in a fraction consisting essentially of DNA and only about 2% protein. This fraction did not elicit the formation of precipitating antibodies, whereas a protein-rich fraction with no reactive antigens did. Treatment of the reactive antigens with DNAase altered some of their properties. On the basis of present evidence, it is suggested that the DNAase-sensitive antigens are complexes containing DNA.