A combined method for detection of cell surface marker expression and bromodeoxyuridine (BrdU) uptake by epidermal cells in suspension.

A rapid and convenient immunocytochemical method is presented for the simultaneous detection of surface antigen expression and S-phase cells using monoclonal antibodies and cells in suspension. The first reagent permits the nature of the cells to be determined while the second immunostaining stage reveals which of these cells are proliferating (BrdU-positive) cells. Staining and fixation conditions have been defined for the detection of cell surface markers by red fluorescence and BrdU labelling by green fluorescence. All the steps were carried out on cells in suspension and the membrane antigen distribution was not affected by the BrdU staining protocol. The method has been applied to two human epidermal cell subpopulations: Langerhans' cells and basal keratinocytes. This technique should have general applicability to the study of the cytokinetic characteristics of phenotypically defined cells in heterogeneous populations.