Studies on the types of immune responses to synthetic antigens in guinea-pigs.

The immune response in guinea-pigs to linear and multichain copolymers of two, three or four different amino acids including tyrosine, glutamic acid, alanine and lysine, was studied. Delayed-type response was favoured in the case of preparations of relatively low molecular weight, containing only tyrosine and glutamic acid in their potential antigenic specificity determinants. Delayed sensitivity to one of these preparations was passively transferred with lymphoid cells. Antibody response resulted from the immunization of animals with preparations of relatively high molecular weight and with a more heterogeneous chemical composition. The antibody formation was intensified and accelerated, when -azobenzenearsonate conjugates of the polypeptides were used as antigens. Variations in the immunizing dose had little or no effect on the nature of the reactions. A response of exclusively delayed type could not be intensified by repeated immunizations. The presence of mycobacteria in the immunizing injection was essential for the elicitation of the response to multichain, but not to linear copolymers.