Isolation of clones of hamster embryo cells transformed by the bovine papilloma virus.

Primary hamster embryo cells infected with bovine papilloma virus (BPV) or treated with BPV DNA-calcium phosphate precipitates showed striking morphological alterations characteristic of transformed cells. Long, spindle-shaped cells grew into dense foci, eventually overgrowing monolayers of normally shaped cells. Samples of these cells were tested for anchorage-independent growth in dilute agarose medium. Cells were able to grow in agarose to form colonies which, when removed from agarose and transferred to liquid medium, established clones. Mockinfected cultures inoculated with plain medium displayed normal cell morphology and growth properties. This is the first report of BPV-transformed cells demonstrating anchorage-independent growth in agarose and the establishment of BPV transformed clones.