Bacterial Antigens

Abstract

THE results of recent work on the nature of certain of the bacterial antigens of gram-negative micro-organisms suggest that these substances are essentially polysaccharide-phospholipin complexes¹. A further component, however, which contains 10 per cent nitrogen, has also been found². Utilizing preparations of antigenic material which had been obtained by the trichloracetic acid method of Boivin¹ or by the diethyleneglycol extraction method³, we have succeeded in removing the phospholipin component² (N: P, 1: 1) from the antigenic complex of B. dysenteria (Shiga) without employing acid, alkaline or enzymic hydrolysis. The phospholipin component cannot be removed by extracting the complex with acetone, ether or ether-alcohol mixture, but is readily eliminated on treatment with a strongly polar solvent such as formamide (dielectric constant 84 at 20°). The antigen dissolves readily in this solvent to give clear, colourless solutions which can be used for the measurement of optical rotation.