Human Fibroblasts Grown for a Year in a Medium of Sheep Plasma and Two Solutions of Known Composition¹

In a previous article, published in this journal, it was shown that human fibroblasts can be grown for a considerable length of time in heterogeneous plasma without using any tissue extract (3). It was possible to keep such tissue growing for a period of three months, using as a medium a mixture of beef plasma and a feeding solution, the main components of which were Witte peptone, glucose, insulin, hemin, thyroxin, and cysteine.

The purpose of this article is to report upon a strain of human fibroblasts which have been kept alive and actively growing for a period of twelve months. Since these cultures were controls in a series of experiments in which human fibroblasts were grown in sheep plasma, the latter was used instead of beef plasma in the preparation of the culture medium. The plasma was prepared from blood taken aseptically from a sheep and therefore did not require sterilization either by treatment with ultra-violet light or by filtering through a Chamber-land-Pasteur candle, as is now done regularly in the preparation of sterile beef plasma for tissue culture work. The citrated sheep plasma, to which equal amounts of calcium Ringer solution and the feeding solution, as formerly described (3), had been added, proved to be an excellent culture medium for human fibroblasts. The latter were grown from several thyroid specimens obtained from the operating room. The tissue grew out as vigorously as when beef plasma is used, showing the same latent period of two or three days. Subcultures were made every fourteen days.