Abstract
Ongoing, high-titer T-cell-dependent immune responses in adult mice, consisting of IgM, IgG, and IgE anti-fluorescein antibodies, can be specifically and substantially reduced (90-99%) when the mice are injected with appropriate doses of fluoresceinated dextran of defined molecular weight and hapten valence. This suppressive form of the antigen is nontoxic and specific, as responses to other antigens are unaffected. The suppression is long lasting and reduces high-affinity antibodies most markedly. Moreover, plasma cell secretion of specific antibody is virtually eliminated. This demonstrates that the reduction in antibody titer is not simply due to masking of serum antibody by the suppressive polymer. The results are discussed with reference to proposed models of B-cell and T-cell tolerance. Extension of these findings to disease-related immunogens may yield effective antigen-specific treatments of human allergy and autoimmune diseases.