Prolonged in vitro Maintenance of Human Diploid Fibroblasts in a New Tissue Culture Medium (PRC-1)

A new medium, designated PRC-1, has been developed that (a) will support proliferation of cells outgrown from human tissue explants and (b) will maintain in culture for prolonged periods human diploid fibroblasts derived from normal, benign, or tumor stromal tissue specimens. Of the 51 tissue specimens used, 28 fibroblastic lines were produced which exceeded their expected life span and lived in the PRC-1 medium for longer than 7 months and up to 25 months (9–91 1:4 subcultivations), as contrasted with lines from the same specimens which were started and maintained in other media (McCoy’s 5a, Ham’s F12, MEM and Leibovitz LI 5). All lines of fibroblastic morphology retained their diploid chromosomal mode throughout their entire serial maintenance in vitro.