Relevant mechanisms of MAIT cells involved in the pathogenesis of periodontitis

Abstract

Mucosal-associated invariant T (MAIT) cells are a group of unconventional T cells that are abundant in the human body, recognize microbial-derived vitamin B metabolites presented by MHC class I-related protein 1 (MR1), and rapidly produce proinflammatory cytokines, which are widely involved in the immune response to various infectious diseases. In the oral mucosa, MAIT cells tend to accumulate near the mucosal basal lamina and are more inclined to secrete IL-17 when activated. Periodontitis is a group of diseases that manifests mainly as inflammation of the gums and resorption of the alveolar bone due to periodontal tissue invasion by plaque bacteria on the dental surface. The course of periodontitis is often accompanied by a T-cell-mediated immune response. This paper discussed the pathogenesis of periodontitis and the potential contribution of MAIT cells to periodontitis.

Keywords: IL-17; alveolar bone resorption; immune reaction; mucosal-associated invariant T cell; periodontitis.

Figure 1

Healthy periodontal tissue and inflamed periodontal tissue: Periodontitis is characterized by hyperplasia of the gingival epithelium, gingival swelling, low gingival attachment, and alveolar bone atrophy.

Figure 2

MAIT cells are activated and produce cytokines under different pathways, which induce osteoblasts to form osteoclasts and induce alveolar bone resorption, promoting the development of periodontal inflammation. (A) Pathogenic bacteria capable of synthesizing riboflavin invade periodontal tissue and activate MAIT cells through the MR1 pathway. (B) Viruses invade periodontal tissue and produce cytokines such as IL-12 and IFN through DCs, causing MAIT cells to be activated through the MR1-independent pathway.