Growth phases of mammalian cells propagated in a serum-free medium

Three distinct phases of growth of a line of mouse-lung fibroblast-like cells adapted to a serum-free medium are described. These are, attachment and growth, “elution” and growth, and fibril formation. Attachment and elution were shown to be independent of the glass surface per se and the pH (6.8–7.2) of the original medium. The conditions and reasons for fibril formation are unknown at this time but are under investigation.