CYTOKERATIN PROFILE OF IMMUNOMAGNETICALLY SEPARATED EPITHELIAL SUBSETS OF THE HUMAN MAMMARY-GLAND

We have used enzymatic and immunomagnetic techniques for the physical separation of the basal and luminal epithelium of the human mammary gl and. Immediately after tissue dissociation and cell sorting, we have e xamined the steady-state CK composition of these cells individually by direct two-dimensional gel electrophoresis of intermediate filament e xtracts. Our results demonstrate that cytokeratins typical of simple a nd stratified epithelial cells are simultaneously expressed by both ma mmary epithelial subclasses in vivo. Moreover, the entire spectrum of cytokeratins seen in vivo is also maintained in short-term cultures of human mammary epithelium. A comparison of the data obtained by direct cytokeratin analysis with published indirect immunolocalization studi es is presented. The ability to isolate purified epithelial subsets fr om normal human breast tissue by a simple immunomagnetic procedure dem onstrated here can facilitate the development of relevant model system s for studying the regulatory components in growth, differentiation an d malignant transformation of the human breast.