Characterization of human sebaceous cells in vitro.

Human sebaceous cells, isolated from adult human skin, were cultured on either bovine type I collagen or mitomycin-C-treated 3T3 fibroblasts. Sebaceous cells, termed "sebocytes", were determined to be epithelial in nature by positive staining with monoclonal antikeratin antibodies BG2 and BG12. However, sebocyte colonies were also negative for keratins found in differentiated cells of keratinocyte colonies, as defined by monoclonal antikeratin antibodies CC2 and CC6. Sebocytes did not produce cornified envelopes in vitro and could only be induced to produce small quantities (less than 5%) of envelopes with a calcium ionophore. Sebocyte growth characteristics in a variety of serum, dexamethasone, and hydrocortisone combinations were significantly different from those of human facial keratinocytes. Sebocytes also displayed a growth curve and plating efficiency that were different from those of keratinocytes. Large lipid droplets within growing sebocytes could be visualized with oil red o staining. Additionally, squalene and wax/cholesterol esters were made by sebocytes in vitro in greater amounts than by facial keratinocytes, as determined by thin-layer chromatography of organic extracts of 3H2O-labeled sebocytes. Sebocytes synthesized greater quantities of lipid, on a per-cell and protein basis, than did keratinocytes.