Isolation of Lymphocytes from Human Skin and Murine Tissues: A Rapid and Epitope-Preserving Approach

Tissue-resident immune cells have been shown to play an important role in skin health and disease. However, owing to limited access to human skin samples and time-consuming, technically demanding protocols, the characterization of tissue-derived cells remains challenging. For this reason, blood-derived leukocytes are frequently used as a surrogate specimen, although they do not necessarily reflect local immune responses in the skin. Therefore, we aimed to establish a rapid protocol to isolate a sufficient number of viable immune cells from 4-mm skin biopsies that can be directly used for a deeper characterization such as comprehensive phenotyping and functional studies of T cells. In this optimized protocol, only two enzymes, type IV collagenase and DNase I, were used to achieve both the highest possible cellular yield and marker preservation of leukocytes stained for multicolor flow cytometry. We further report that the optimized protocol may be used in the same manner for murine skin and mucosa. In summary, this study allows a rapid acquisition of lymphocytes from human or mouse skin suitable for comprehensive analysis of lymphocyte subpopulations, for disease surveillance, and for identification of potential therapeutic targets or other downstream applications.