Experiments on Immunization with Haptens

Abstract

It is known that the specific substance contained in Forssman's antigen which as such is only slightly antigenic 1 can be restored to high antigenic activity by the admixture of proteins foreign to the animal immunized. Recently a second method of producing the same result has been found, which consists in the injection of the hapten along with kaolin. 2 Similar effects have been described by Zozaya 3 with mixtures of a polysaccharide from B. anthracis, and collodion particles.

We had no difficulty in corroborating the findings of Gonzalez and Armangué, and in addition we observed that hemolysins for sheep blood could be produced by injecting the Forssman hapten mixed with a suspension of collodion particles. These observations suggested the possibility that other ways of increasing the slight antigenic activity of the hapten might be found. In fact, in some animals we obtained higher titers than in the controls, on injecting the specific substance and at the same time trypan blue or turpentine, but the results were quite irregular. A single attempt to produce precipitins and bacterial agglutinins by Zozaya's method was not successful. However, it was possible to produce agglutinins and precipitins of moderate titer by the injection of a specific substance prepared from V. cholerae which was adsorbed to charcoal. This substance was prepared by extraction with 75% alcohol followed by treatment with alkali according to the method of Landsteiner and Levene. 4 (The sera of 5 rabbits after 5 intraperitoneal injections of the specific substance from V. cholerae adsorbed to charcoal gave, after 2 hours at 37°C., agglutinin titers of (1) 1:1600, (2) 1:100, (3) 1:50, (4) 1:100, and (5) 1:50, respectively.