A serum-free medium for the Mishell-Dutton system.

A serum-free medium which provides high recoveries of plaque-forming cells in the primary immune response to sheep erythrocytes is described. In this medium the serum was replaced by heated fetuin and by excess of nonessential amino acids. Glycopeptides, obtained by excessive pronase treatment of fetuin were partially capable of replacing the nonhydrolyzed fetuin.