Regulation of the binding of antigen to receptors by soluble antibodies: in-vitro competition and synergism for dinitrophenylated human serum albumin and ε-DNP-lysine

Abstract

Soluble anti-DNP antibodies competed or collaborated in the binding of dinitrophenylated human serum albumin to anti-DNP or anti-HSA antibodies attached to Sepharose depending, directly, on the ratio of the concentrations of soluble to insoluble antibodies and, inversely, on that of the antigen. Soluble antibodies competed or collaborated with the insoluble ones by polymerizing the antigen and either incorporating or not incorporating the insoluble antibodies into the polymer. Furthermore, a clear advantage of insoluble antibodies over soluble ones in the binding of antigen was found, and is perhaps indicative of the importance of the reactions' micro-environment and of the secondary non-specific forces that may be participating. Thus, by analogy, the role of circulating anti-hapten and anti-carrier antibodies on the regulation of the immune response may be either positive or negative depending on their concentration, on the number of cellular receptors available, on the micro-environment of the cell surface and on the magnitude of the antigenic challenge. A simple rule that relates some of these variables with the immune response is discussed.