Peptide immunotherapy for inhaled allergens

Abstract

Effective allergen immunotherapy has been studied for more than a millennium and since that time researchers have been working to improve efficacy and reduce the side effects. The mechanism of allergen immunotherapy is to induce regulatory T (T_reg) cells and reduce T helper (Th) 2 cells to induce class switching from IgE to IgG and induce blocking antibodies to inhibit IgE allergen binding. Modification of allergens and routes of treatment has been performed. Among them, many researchers were interested in peptide immunotherapy. Since T cell epitope peptide has no IgE epitope, it is unable to bind IgE, but rather induces T_reg and reduces Th2 cells, respectively, and therefore, considered an ideal therapy. Results from cellular and animal model studies have been successful, however in clinical studies, T cell peptide immunotherapy has failed to show efficacy and caused side effects, because of the high effective rate of placebo and the development of IgE against T-cell epitope peptides. Currently, the modifications of IgE-allergen binding by blocking antibodies are necessary for successful allergen immunotherapy.