The Significance of the Dose of Antigen in Immunity and Tolerance

The discovery of the phenomenon of immunological tolerance stimulated study of the significance of the size of the dose of antigen in immune phenomena. It has become apparent that antibody synthesis is not the only outcome of injecting antigen into an animal and that a specific inhibition of antibody synthesis can also occur. The size of antigen dose may determine whether or not immunity or tolerance is induced, but the physical nature of the antigen and the ontogenetic stage of development of the animal also play a significant part. Apart from the question of balance of the reaction between immunity and tolerance, the significance of a study of the effect of the antigen dose as a factor which regulates the differentiation of immunologically competent cells acquired importance. The centre of these regulation processes appears to be the control of the molecular type of antibodies produced, which is reflected in the kinetics of the immune response and the development of immunological memory.