ABSTRACT
In the experiments by Rheinwald and myself on isolation of teratomal keratinocytes, this chapter shows that their growth in culture depended on the presence of fibroblast support and for this purpose we used 3T3 cells, lethally irradiated to prevent their own growth. This worked so well that it became the basis of all future work on human keratinocyte cultivation and the 3T3 cell line is used everywhere today to support the growth of cultured human keratinocytes. The chapter examines the effects of camp on the proliferation of cultured keratinocytes. Hitherto it had been thought that camp brought about arrest of cell growth. But they found that dibutyryl camp promoted keratinocyte proliferation. The same was true for methyl isobutyl xanthine, an inhibitor of phosphodiesterase and for isoproterenol, a well-known beta agonist. But the most effective growth-promoting agent was cholera toxin.
