ALLERGEN-SPECIFIC IMMUNOTHERAPY - A ROLE FOR T-CELL ANERGY

T cells induce both a specific and nonspecific effect during an allerg ic immune response. Antigen receptors on T cells recognize peptide fra gments of foreign proteins associated with products of the major histo compatibility complex expressed on the membranes of antigen-presenting cells. The recognition event triggers T-cell activation, secretion of lymphokines, and the isotypic switch from IgG to IgE synthesis, which is mediated by IL-4. This cascade results in sensitization of the mas t cell, elaboration of various mediators, and local tissue inflammatio n. The interaction of the antigen-presenting cell and T cell holds imp lications for therapeutic modulation of the allergic response by the a ntigen. Animal studies have demonstrated that peptides containing T-ce ll epitopes can be used to control the immune response. Peptides deliv ered with adjuvants cause stimulation, whereas peptides delivered with out adjuvants result in specific T-cell anergy or tolerance. Soluble p eptide can be used to induce tolerance to the peptide and to protein m olecules containing that peptide. The administration of peptides conta ining T-cell epitopes to allergic individuals may thereby represent an important component of the next generation of allergen-specific immun otherapy.