IADR Abstract Archives

Distinct Roles to Gingival Epithelial Sentinels in Different Periodontitis Models

Objectives:
The gingival epithelium is embedded with special resident leukocytes - Langerhans cells (LCs) and γδT cells - strategically located to monitor the dental biofilm. An unbalanced interplay between the biofilm and the immune system results in the development of the inflammatory disease – termed periodontitis. To study periodontitis, various experimental models were developed, the most common are ligature-induced periodontitis (LIP) and oral pathogen-induced periodontitis (OIP). This study aims to address the role of LCs and γδT cells in each modality, to better understand the mechanisms mediating periodontitis,

Methods:
Experimental periodontitis (LIP or OIP) was induced in transgenic mice enabling conditional ablation of LCs (langerin-DTR mice) or γδT cells (Tcrd-GDL) in vivo. Flow cytometry and RT-PCR analyses were used to dissect gingival immunity and alveolar bone loss was quantified by µCT.

Results:
In vivo ablation of LCs or γδT cells during LIP had no impact on local inflammation nor the level of alveolar bone loss. On a contrary, both cells play a critical but inverse role in gingival immunity and alveolar bone loss in the OIP model. Whereas LCs protect the host by down-regulating pathogen-induced inflammation, γδT cells enhance pathogen-induced bone loss. Further analysis revealed that γδT cells orchestrate the recruitment of monocytes and neutrophils to the gingiva shortly after the exposure to pathogen. At later stages, the absence of γδT cells reduces the expression of the osteoclastogenic molecule RANKL and down-regulated the development of T regulatory cells in the gingiva.

Conclusions:
These findings highlight the diverse role of LCs and γδT cells in the two common periodontal models, suggesting the engagement of fundamentally distinct immunopathological mechanisms in each modality. In a broader view, this demonstrates the complexity of periodontitis which could be caused by various mechanisms.


2021 Israeli Division Meeting (Jerusalem, Israel)

2021

  • Barel, Or  ( The Hebrew University of Jerusalem , Jerusalem , Jerusalem , Israel )
  • Hovav, Avi-hai  ( The Hebrew University of Jerusalem , Jerusalem , Jerusalem , Israel )
  • NONE
    Oral Session
    Oral Session 4