γδT cells in oral tissue immune surveillance and pathology

Abstract

The oral mucosa’s immune system is composed of tissue-resident and specifically recruited leukocytes that could effectively tolerate a wide range of microbial and mechanical assaults. Shortly after CD4+ helper T cells (TH17 cells) that produce interleukin 17 (IL-17) were identified, it was discovered that γδT cells could also induce substantial levels of this pro-inflammatory cytokine. In the past decades, it has become clear that due to a complicated thymic program of development, γδT cells frequently serve as the primary sources of IL-17 in numerous models of inflammatory diseases while also assisting in the maintenance of tissue homeostasis in the skin and intestine. But it wasn’t until recently that we took thorough insight into the complex features of γδT cells in the oral mucosa. Most gingival intraepithelial γδT cells reside in the junctional epithelium adjacent to the dental biofilm, suggesting their potential role in regulating oral microbiota. However, inconsistent results have been published in this regard. Similarly, recent findings showed contradictory data about the role of γδT lymphocytes in experimental periodontitis based on different models. In addition, conflicting findings were presented in terms of alveolar bone physiology and pathology underlying the oral mucosa. This review provided an overview of current knowledge and viewpoints regarding the complex roles played by oral-resident γδT cells in host-microbiota interactions, gingivitis and periodontitis, bone physiology and pathology.

Mouse gingival single-cell transcriptomic atlas identified a novel fibroblast subpopulation activated to guide oral barrier immunity in periodontitis

“…The previous studies suggested gingival intraepithelial γδT cells ( Chen et al, 2022 ), a subset of neutrophils ( Fine et al, 2016 ), macrophages ( Metcalfe et al, 2021 ), and dendritic cells ( Hovav, 2014 ) should serve the candidate immune surveillant in the oral barrier tissue. These immune cells recognize the pathological signals through the TLR sensing mechanism.…”

Fibroblasts at the curtain call: from ensemble to principal dancers in immunometabolism and inflammaging

“… 9 P. gingivalis and its virulence factors have been extensively studied in consortium with other species characterizing a polymicrobial synergy, 18 which is directly associated to alveolar bone loss. 19 In this aspect, many cell types are important to orchestrate tissue response and bridge the link to the overall systemic health, including antigen-presenting cells, 20 T cells, 21 , 22 and architectural stromal cells, which can assume an immune phenotype and function on demand. 23 …”

Sex-Related Effect of Aging in Gingival Gamma-Delta T Cells

“…While Vγ6 cells develop only in the embryonic thymus and are maintained at local tissue sites by self-renewal, Vγ4 and Vγ1 cells develop in both the embryonic and adult thymus and can be reconstituted from the circulation throughout life. Moreover, Vγ6 cells appear to be dependent on the microbiota, while Vγ4 and Vγ1 cells are triggered by mechanical damage (Chen et al 2022). Specific functions of immune surveillance and wound healing (Vγ4 and Vγ6 in skin and oral mucosa) and tissue repair (Vγ7 in the intestine) have been shown (Fischer et al 2020; Ribot et al 2021).…”