Specificity of Hapten-Reactive T and B Mouse Lymphocytes

Immunization of mice with hapten-protein conjugates leads to the appearance of increased numbers of hapten-specific antigen-binding cells of both T and B origin. as well as to the formation of anti hapten antibody-secreting cells. The affinity of cellular receptors of hapten-reactive T and B cells was studied after immunization with different antigen doses at different time intervals. It was found that the affinity of secreted antibodies of the IgG class as well as of B-cell receptors for hapten was dose- and time-dependent. The affinity of hapten-reactive T cells for the hapten itself was low, irrespective of dose and time. Binding strength of T-and B-cell receptors was also investigated with the aid of mono- and multivalent homologous and heterologous hapten-carner complexes. The affinity of T cells for the homologous monovalent ligand was considerably higher than for the hapten itself or a heterologous monovalent ligand. indicating carrier contribution to T-receptor affinity. The contribution of carrier to the affinity of 7S antibodies or B-cell receptors was relatively small The avidity of hapten-specific cells for multi valent ligands was high in both T and B cells, but the increment in avidity with such ligands compared to monovalent ligands was less pronounced in T cells