Potency of T-Cell Epitope-Based Peptide Vaccines in Food Allergy Treatment

Abstract

The prevalence of food allergy is increasing with cow’s milk and peanut being major culprit foods, particularly in young children. Currently, only allergen avoidance or drugs that aid symptom relief are available for food allergy treatment. As allergen immunotherapy (AIT) is the only treatment that really tackles the cause of allergy, there is an urgent need for improved cow’s milk and peanut-specific AIT. Although AIT with whole allergen extracts is already used for the treatment of allergies to many aeroallergens, its potential for food allergy treatment is often questioned due to safety, efficacy, and compliance issues of these conventional types of AIT. Based on the central role of T cells in orchestrating allergic responses, AIT with T-cell epitope-based peptide vaccines may provide a better alternative in treating peanut allergy than conventional AIT with whole allergen extracts. These peptide vaccines comprise allergen peptides that consist of dominant T-cell epitopes that are too short to cross-link mast cell-bound allergen-specific immunoglobulin (Ig) E antibodies. Therefore, these vaccines are considered unable to induce adverse allergic responses. The aim of this literature review is to assess the potency of peptide-based immunotherapy in cow’s milk and peanut allergy treatment by focusing on its safety, efficacy, underlying immunological mechanisms of action, and practical applicability. Peptide vaccine treatment influences T-cell polarization by establishing alterations at the level of interacting immune cells upon allergen exposure. There are four major potential underlying mechanisms by which these altered immune cell interactions favor tolerance induction. These mechanisms are indicated to be an immune deviation, anergy, deletion, and active suppression. Peptide vaccine treatment alters immune cell interactions in such a way that tolerance is induced. These vaccines establish these altered interactions by their characteristic physical form, their tolerance-favoring route of administration, and high-dose allergen exposure. The results of trials focusing on peptide vaccine treatment are truly encouraging. Nevertheless, further research is needed to evaluate whether these results are of predictive value for the potency of these peptide vaccines in allergy treatment. Much of what has been learned about peptide vaccines in cow’s milk and peanut allergy can be applied in the treatment of other food allergies with severe allergic manifestation, like tree nuts and fish and shellfish allergies. Although peptide-based AIT has the potential for treating food-allergic individuals in the future, strict avoidance of allergens remains the standard approach for food allergy management for now.