Abstract
A serum-free medium, designated S4 [consisting of Eagle's Minimum Essential Medium supplemented with the following components (mg/liter): endothelial mitogen, 100; vitamin C, 1; insulin, 5; cholera toxin, 0.01; putrescine, 8; sodium selenite, 0.0043; MgCl2 X 6H2O, 40; and albumin, fatty acids, amino acids, vitamins, and trace elements], has been established to select for the growth of Schwann cells from primary cultures of dissociated neonatal rat sciatic nerve in the absence of neurons and without exposure of the cells to serum or antimitotic agents. By immunological criteria, confluent primary cultures, grown on a substrate of extracellular matrix derived from cultured bovine aorta endothelial cells, consist of approximately 90% Schwann cells after maintenance in this serum-free medium. Secondary cultures of at least 99% purity may be established after treatment of primary cultures maintained in S4 with antiserum against a fibroblast surface antigen, Thy 1.1, in conjunction with complement. Such secondary Schwann cells continue to proliferate in S4, with no decrease in purity, through at least 4 passages.