RORγt-APCs: The New Masters of Oral Tolerance.

Oral tolerance is defined by the hypo-responsiveness of our body to fed antigens, and its failure can lead to immune-mediated diseases, such as allergy, chronic inflammation and autoimmune diseases. Decades of research have demonstrated that antigen-presenting cells (APCs) promote oral tolerance by inducing regulatory T cells (Tregs) and/or suppressing T cell activation. Nevertheless, the exact subsets of APCs involved in the presentation of antigens to T cells remains under debate. Recent exciting studies have described several subsets of RORγt (Retinoic acid-related orphan receptor gamma t)-APCs that have key roles in regulating immune responses and oral tolerance. In this review, we briefly summarize the current knowledge about oral tolerance development and then focus on discussing how these newly identified RORγt-APCs act as crucial regulators of this process.