Expression of differentiation molecules is preserved in human fetal kidneys during culture

A model has been developed in our laboratory to culture human fetal kidney (Brière 1987). This system is original because it is realized in serum-free Leibovitz's L-15 medium unsupplemented with hormones. Since the culture conditions are minimal for growth and differentiation, many parameters had to be analysed to verify the validity of the system. It was shown that the overall architecture of the explants was preserved during the culture period as well as other morphological and biochemical characteristics. Cells in different populations of the cultured explants keep synthesizing DNA although at a decreased rate. The aim of the current work was to further evaluate the model by studying the expression of some renal cell differentiation antigens (CD24, CD9, CALLA/CD10) in the fetal kidneys during culture. The 4 selected monoclonal antibodies (OKB2, IOB2, IOT5a, IOB3) detected the corresponding surface antigens in various developing renal structures present in uncultured explants. It was observed that these antigens were well preserved during culture and were still expressed on the same structures after 5 d. The present culture model appears as a valuable tool to assess kidney development, and the above mentioned cell surface antigens might be used as markers to study nephrogenesis or the differentiation of membrane specializations.