Fig. 1

Definition of distinct human epidermal mononuclear phagocytes by flow cytometry. Mononuclear phagocytes were liberated from human epidermis using trypsin or Type IV collagenase. a Flow cytometry was used to define three subsets of CD3⁻/CD19epidermal MNPs from collagenase digested tissue (i) Langerhans cells (green) were defined as HLA-DR^intermediate, CD1a^{very high}, langerin^high, CD33⁺, CD11c⁻, MR⁻ (ii) epidermal CD11c⁺ DCs (blue) were defined as HLA-DR^high, CD1a⁺, langerin^low, CD11c⁺, MR⁺ (iii) epidermal CD33^low cells (black) were defined as HLA-DR^low, CD1a⁺, langerin^high, CD33^low, CD11c⁻, MR⁻. Representative data of 75 individual donors is shown. b CD11c expression was compared on cells derived from trypsin and collagenase digestion. The blue circle indicates the CD11c⁺ cells detected in collagenase digested tissue that are not observed in trypsin digested tissue. Representative data of five individual donors is shown. c The relative proportion of each subset CD45⁺ HLA-DR⁺ gate after collagenase digestion was determined and is shown as a mean ± the standard deviation with each dot representing an individual donor. Statistics were generated using the Mann–Whitney test. *p < 0.05; **p < 0.01; ***p < 0.001; ****p < 0.0001 (n = 75)