Salivary Lymphocyte Phenotypes Differ from Blood and Serve as a Model for Other Mucosal Fluids

Area of Science:

• Immunology
• Cell Biology
• Oral Health

Background:

• The oral cavity is a key part of the body's mucosal immune system, interacting with numerous antigens.
• While soluble mediators of mucosal immunity are well-studied, immune cell phenotypes remain less understood, hindering disease pathogenesis research.

Purpose of the Study:

• To review the importance of immune phenotyping in mucosal secretions.
• To demonstrate the utility of flow cytometry for quantifying diverse lymphocyte phenotypes in stimulated whole mouth fluid (SWMF).

Main Methods:

• A review of immune phenotyping techniques was conducted.
• Flow cytometry was used to detect and quantify lymphocyte phenotypes (Th17, Th22, Tfh, Tregs, NKT, NK, ILC1, ILC2, ILC3) in SWMF and peripheral blood mononuclear cells (PBMC) from 119 participants.

Main Results:

• Flow cytometry reliably detected various immune cell phenotypes in SWMF.
• Frequencies of Th17, Th22, Tfh, and NK cells were higher in SWMF than in PBMC.
• Phenotype correlations suggested a specific mucosal origin for cells detected in SWMF.

Conclusions:

• Flow cytometry is effective for detecting a broad range of lymphocyte phenotypes in SWMF.
• This technique holds promise for investigating the immunopathogenesis of diseases affecting mucosal sites.