Flow Cytometric Immunodissection of the Human Nephron in vivo and in vitro

In the present article, we show that flow cytometric immunodissection of cells immediately following their preparation from a tumor nephrectomy specimen is an accurate way of obtaining pure human primary cultures of proximal convoluted tubule origin, proximal straight tubule origin, distal tubular origin and/or collecting duct origin. By studying the expression of a panel of cell surface markers in these purified cultures, we could identify a number of markers that retain their lineage specificity in vitro. Using these appropriate stable markers, flow cytometry provides a simple yet accurate way of determining cell composition in previously unsorted (mixed type) tubular epithelial cultures in terms of proximal versus distal tubule/collecting duct subpopulations. Both subpopulations in mixed type cultures are shown to retain functional characteristics of their in vivo counterparts (glucose uptake, hormonal stimulation of adenylate cyclase) as well as cell type-specific response patterns (such as inducibility of cell adhesion and histocompatibility molecules), indicating the usefulness of studying cell responses in vitro in a cell-type-dependent way. Finally we illustrate that multi-parameter flow cytometry is a powerful tool for assessing constitutive characteristics of and/or responses by the distinct cell subpopulations present in mixed type cultures.