Characterization and TCR variable region gene use of mouse resident nasal γδ T lymphocytes

Tissue-resident γδ T lymphocytes, such as dendritic epidermal T cells, intestinal intraepithelial lymphocytes (IEL), and resident pulmonary lymphocytes, are known to support local tissue homeostasis and host defense. Inhaled antigens, toxins, and microorganisms first interact with the immune system through contact with the nasal mucosa. Herein, we characterized two populations of resident nasal lymphocytes (RNL) that are present in the nasal mucosa: nasal IEL (nIEL) and nasal lamina propria lymphocytes (nLPL). γδ TCR⁺ and αβ TCR⁺ nIEL and nLPL were detected by immunofluorescent staining. Mononuclear cells (5-15%) were CD3⁺ RNL by FACS analysis. Among the CD3⁺ RNL, 20-30% were GL3⁺ γδ T cells, which were double-negative for CD4 and CD8 and predominantly expressed a Vγ4/Vδ1 TCR. These results demonstrate that RNL might be crucial for the host defense and tissue homeostasis in the nasal mucosa.