Studies on the immune response to fixed antigens. IV. Recall of immunologic memory with fixed antigens.

The chemically modified antigens, trinitrophenylated sheep red blood cells (SRBC) and glutaraldehyde-SRBC, elicited specific secondary responses in mice but were unable to induce primary responses. They also induced specific immunologic memory. The secondary immune response was directed to the specific determinants of SRBC but not to new antigenic determinants created by the chemical modification process. The interpretation of these findings is discussed in relationship to the ability of fixed antigens to be processed by macrophages.