Growth Inhibition of Polyoma-Transformed Cells by Contact with Static Normal Fibroblasts

Abstract

The growth of polyoma-transformed BHK21 cells was studied in mixed cultures with normal mouse fibroblasts. On coverslips in excess medium, normal fibroblasts undergo one or two divisions after the cells become contiguous. Py-cell growth was not inhibited by contact with confluent fibroblasts which were still dividing, but the Py cells were rapidly inhibited after contact with fibroblasts which had become static. Further experiments confirmed the earlier view that the inhibitory effect was not due to a general change in the medium but was only brought about when cells were in contact or close proximity.