Transformed cell lines derived from progressor sarcoma virus (Moloney) induced tumors: I. Differences in pathogenicity between C type viruses from producer and helper virus infected nonproducer cells

Cell lines derived as producers and nonproducers from progressor Moloney sarcoma virus induced tumors showed differences in the rescuability of the viral sarcoma genome and in biological activities of released virus. Restoration of transformation defective variants is demonstrated.