Receptors on immunocompetent cells. V. Cellular correlates of the "maturation" of the immune response.

During the course of the immune response to dinitrophenylated guinea pig albumin (DNP-GPA), a striking and parallel increase in avidity for epsilon-DNP-L-lysine occurs in the receptors on antigen-binding lymphocytes, antibody secreted by individual plaque-forming cells, and serum antibody molecules. A detailed analysis of the avidity distribution of antibody produced by plaque-forming cells indicates that this "immunologic maturation" is primarily due to a preservation of the high avidity subpopulation and a striking loss in the low avidity population rather than to sequential appearance of these cells. Moreover, the demonstration of the increased avidity of receptors of antigen-binding lymphocytes, which appear to be precursors of antibody-synthesizing cells, strongly suggests that the antigen-driven selectional process operates primarily on this cell type.