Immunologic Properties of an Antigenic Material Isolated from Eberthella Typhosa

Abstract

An antigenic material has been prepared from cultures of E. typhosa grown in a synthetic medium. In small quantities it is lethal for mice and rabbits. In sub-lethal amounts the antigen induces leucopenia and fever in rabbits, and leucopenia in guinea pigs, rats and mice. Upon acid hydrolysis an innocuous acid-soluble material and an acid insoluble fraction possessing toxic properties are released. The intact antigen is heat stable. In immunized rabbits the antigen is still capable of inducing leucopenia and fever. Washed precipitates from mixtures of the antigen and an excess of antibody are still capable of causing these reactions when injected intravenously into normal rabbits. The antigen induces the Shwartzman reaction in rabbits when employed either as the preparatory or eliciting agent. The combination of antigen and antibody in the form of a precipitate will elicit the Shwartzman reaction in animals prepared by intracutaneous injection of the antigen. The precipitate has only relatively slight activity when used as the preparatory agent. The possible relationship of these findings to the immunologic behavior of the somatic antigen and to certain of the manifestations of typhoid fever are discussed.