Journal of Cell Science, Vol 3, 603-613, Copyright © 1968 by Company of Biologists

Revised on January 10, 1968

Interaction Between Normal and Transformed Bovine Fibroblasts in Culture

II. Cells Transformed by Polyoma Virus

¹ Group of Cell Biology, The Wallenberg Laboratory, University of Uppsala, Uppsala, Sweden; Department of Pathology, University of Uppsala, Uppsala, Sweden
² Group of Cell Biology, The Wallenberg Laboratory, University of Uppsala, Uppsala, Sweden; Pathology Department, University of Colorado Medical Center, Denver, Colorado, 80220, U.S.A.

Bovine fibroblasts transformed by polyoma virus have been cocultivated with syngeneic or allogeneic normal cells. The growth of the transformed cells was inhibited by the presence of normal cells. The strongest depression was obtained when a dense stationary layer of normal fibroblasts was challenged by polyoma cells. The inhibition was least pronounced if normal and transformed cells were simultaneously seeded.

Polyoma-transformed cells were identified by radioautography after incorporation of tritiated thymidine. After 96 h of contact with stationary normal cells the number of grains per nucleus and the number of labelled nuclei had not changed indicating strong depression of DNA synthesis. A deficient attachment or premature detachment of polyoma cells could not account for the observed failure of growth in the normal/polyoma mixed cultures.