Early effect of interferon on mouse leukemia cells cultivated in a chemostat

Mouse interferon preparations inhibited the multiplication of mouse leukemia L 1210 cells cultivated under steady-state conditions in a chemostat. The use of this sensitive and controlled system led to the detection of a rapid inhibition in the incorporation of (3-H)thymidine into cellular acid-precipitable material 2 hr after the addition of interferon, whereas an effect on cell multiplication was not detected until 22 hr later. Interferon exerted only a transitory effect on the incorporation of (3-H)uridine into acid-precipitable material and no effect on the incorporation of 14-C-amino acids into cellular protein. It is suggested that the chemostat offers many advantages for the investigation of those physiologic factors or chemotherapeutic substances that modify cell division.