II. Experiments on Immunization with Haptens

Abstract

Experiments were previously reported 1 confirming the findings of Gonzalez and Armangué that the antigenic properties of alcoholic organ extracts containing Forssman's substance are strikingly increased by adsorption to inorganic adsorbents such as kaolin. Additional evidence for this effect has been advanced by the above authors recently, 2 in particular by establishing that it can be observed with a variety of adsorbents.

To study further the phenomenon discovered by Gonzalez and Armangué, experiments similar to those referred to were carried out with Forssman preparations which had been freed from a large portion of inactive material originally present, by methods described previously. 3 Of the two preparations used, one was easily soluble in water and the other was brought into water solution by the addition of phenol.

It appeared that with these substances practically no antigenicity could be induced by adsorption to kaolin whereas on injecting rabbits with the same preparations mixed with pig serum, all of the animals reacted and the majority produced sera of good titer.

These results suggest the possibility that substances other than the specifically reacting haptens have a part in the reactivation by non-antigenic adsorbents. In this connection it may be mentioned that alcoholic organ extracts (e. g., extracts of horse kidney) prepared by heating, which may be supposed to have a higher content in proteins, are by themselves more apt to induce the production of hemolysins than those prepared at ordinary temperature.∗

In experiments with adsorbed bacterial carbohydrates, also, the effect seems to vary with the degree of purity of the substances. Preparations of cholera carbohydrate giving little or no biuret reaction were inactive or only faintly antigenic upon adsorption to charcoal, while preparations giving a strong biuret reaction, though very slightly antigenic themselves (following treatment with alkali), were definitely active in inducing the formation of agglutinins and precipitins in rabbits, after adsorption to charcoal.