Isolation of subpopulations of murine epidermal cells using monoclonal antibodies against differentiation-related cell surface molecules.

Monoclonal antibodies (mAbs) against epithelial cells were prepared by immunization of rats with lyophilized murine epithelia. Screening against tissue sections and epithelial cell suspensions permitted identification of mAbs against surface molecules that are expressed early in cell differentiation. Staining with these mAbs followed by fluorescence-activated cell sorting enabled isolation of subpopulations of basal epithelial cells. Staining these subpopulations with antibodies against known differentiation markers (cytokeratins and bullous pemphigoid antigen) and measurements of cell size indicated that they represented fractions of the basal cell population in sequential stages of early differentiation. Labeling mice with bromodeoxyuridine at various times prior to cell isolation showed that the least-differentiated basal cells cycle more slowly than those at later stages, data which support the concept of a differentiation-related, hierarchical pattern of organization of the proliferative compartment.