Cholesterol requirement for growth of IR983F and P3X63-Ag8-U1 myeloma cells in serum-free medium.

Cholesterol, a major lipid component of the plasma membrane, is thought to have profound effects on the structure and function of cells. Most animal tissues are capable of synthesizing cholesterol de novo from acetate; however, there are relatively few mammalian cells in vitro expressing an absolute requirement for an exogenous source of cholesterol. In this paper, it was shown that both IR983F (983) rat myeloma cells and P3X63-Ag8-U1 (P3U1) mouse myeloma cells which had been cultivated in serum-free medium containing cholesterol for more than 6 months still required cholesterol in vitro for growth in serum-free medium. Optimal growth of 983 and P3U1 occurred in cholesterol concentrations of 15 and 5 micrograms/ml, respectively. Moreover, it was demonstrated that the cholesterol could be replaced by human low density lipoprotein in a concentration of 10 micrograms/ml but not by mevalonic acid lactone. In contrast to the parental myeloma cells, hybridoma cells derived from the mouse myeloma cells which had been cultivated in serum-free medium containing cholesterol for more than 6 months did not require cholesterol.