CD226/TIGIT: candidates for new allergy treatments

Abstract

Costimulatory molecules on the surface of T cells enhance or suppress T cell activation by binding to their ligands expressed on antigen-presenting cells. CD226 and TIGIT bind to a common ligand, CD155 and regulate immune responses by activating or suppressing CD4⁺ T cells, respectively. CD226 and TIGIT play important roles in immune function, not only in the activation of CD4⁺ T cells, but also in the enhancement of regulatory T cell function, the differentiation of follicular helper T cells and the activation and subsequent elimination of innate lymphocytes. In this review, the functions of CD226 and TIGIT in each immune cell and their roles in allergic diseases are discussed.