The Process of Transformation of Antigenic Type in Paramecium Aurelia, Variety 4

Abstract

In a quantitative study of antigens in stock 51 paramecia, ability to absorb antibodies is used as a measure of antigen, and immobilization time is used as a measure of antibody. The effect of serum treatment is not immediate for type D animals immobilized with dilute anti-D serum for up to 2 hrs.; although there is a reduced capacity to absorb D-type antibodies, there is at first no effect of anti-B serum. Transformation of antigenic type takes place only when a period of growth follows the serum treatment. The transformation is progressive and the time required is inversely related to the strength of the original treatment. The necessity for active metabolism during the transformation is manifest in the failure of animals treated in weak serum to transform if they are starved for 5 days. Starved animals do not lose their reactivity to anti-D. These results are said to strongly support the theory that the type selected by a given stock is dependent upon competition between plasmagenes. The indications are that treatment by anti-D serum partially or completely suppresses the further production of D antigens, from which it would appear that the plasmagenes are the antigens themselves. Attention is called to the similarity of the antigen transformation to enzymatic adaptations in yeast and bacteria.