Abstract
Rat cells transformed by B77 virus did not produce virus as assayed by infectivity and interference tests. Each of the transformed rat cells contained the complete virus genome, since virus capable of converting chicken and rat cells could be rescued from them. Experiments are presented supporting the hypothesis that B77 virus changes genetically during residence in the rat cells. Infection of rat cells by B77 virus was followed by morphological conversion of some cells. Other cells contained the virus genome but were not transformed: this is termed abortive infection.
* Present address: Department of Virology, Hebrew University-Hadassah Medical School, Jerusalem, Israel.