Isolation and preliminary biochemical characterization of the human epidermal Langerhans cell

A method is described for the isolation of human epidermal Langerhans cells (LC). Following the disaggregation of the epidermis by gentle trypsinization, the cell suspension is incubated with the fluorescein-conjugated monoclonal antibody OKT6. Using a fluorescence-activated cell sorter, a subpopulation is selected on the basis of positive fluorescence and low forward-scatter, the latter parameter reducing contamination by LC-keratinocyte clusters. The LC averaged 1.7% of the original epidermal preparation. The purity averages 83% as judged either by OKT6 binding or by ATPase activity. Biochemical measurements indicated that the activity of lysosomal enzymes was low with the exception of alpha-mannosidase, which was about 12-fold higher than that of the keratinocyte. The activities of 3 enzymes of intermediary metabolism suggest that the utilization of glucose by the LC is considerably greater than that of the keratinocyte.