Fig. 1

Dendritic cells in the sublingual and buccal (SL/B) Tissue of rhesus macaques. Paraffin-embedded sublingual and buccal tissue sections were stained with a Hematoxylin and eosin and imaged by light microscopy (scale bar, 500 μm) or b anti-Langerin and analyzed by immunohistochemistry (scale bar, 200 μm). Arrows show Langerin⁺ cells stained in red. c Representative flow plots showing dendritic cell (DC) subsets in PBMC, sublingual tissue, buccal tissue, and the submandibular, submental, and inguinal lymph nodes. Top row; CD45⁺CD3⁻CD20⁻HLA-DR⁺CD14⁻CD16⁻ cells were gated for plasmacytoid DC (CD123⁺BDCA-1⁻, orange) and conventional DC (CD123⁻BDCA-1⁺, blue) markers. Middle row; CD45⁺CD3⁻CD20⁻HLA-DR⁺ cells were gated for Dermal DCs (CD14⁺DC-SIGN⁺, green). Bottom row; frequencies of DC subsets in different tissues (*, p < 0.05, Wilcoxon matched-pairs test). Data representative of samplings from six independent animals, n = 5 (PBMC) n = 6 (buccal, sublingual), n = 3 (submandibular, submental, and inguinal lymph nodes). Samples from the same animal were paired together. d Detection of aldehyde dehydrogenase (ALDH) activity in buccal or submandibular DCs using the ALDEFLUOR^TM fluorescent reagent. Control samples were used to set gating. Representative flow plots are shown on top measuring ALDH activity in conventional DCs in buccal tissue compared to submandibular lymph nodes. Bottom, frequencies of ALDEFLUOR⁺ conventional DCs (blue) and dermal DCs (green) in PBMCs (n = 2), buccal (n = 3) and sublingual tissue (n = 3), and submandibular (n = 3) and submental lymph nodes (n = 3) (*, p < 0.05; **, p < 0.01; Mann–Whitney test). PMBC, peripheral blood mononuclear cells; SL/B, sublingual and buccal tissue. Box and whiskers plot in c, d; box extends from 25th to 75th percentile, the line indicates median, whiskers indicate min and max values