Kinetics of Human Beta Interferon Production Under Different Temperature Conditions

Abstract

The kinetics of interferon synthesis in poly I: poly C induced human fibroblasts (FS-4) as measured under various temperature conditions. The use of a constant temperature during induction (34°C) followed by a combination of temperatures during the production phase (37°C for 1 h followed by a shift to 30°C) resulted in a higher sustained rate of interferon synthesis between 24 and 48 h. The initial short exposure of cells to 37°C was shown to be essential to obtaining higher rates of synthesis in the late stages of production, but yields were not enhanced by increasing the period of exposure. Exposure of cells to either 1 or 10 μg/ml of cycloheximide during the 37°C period did not diminish the rates of synthesis between 24 and 48 h suggesting that the observed effect did not require protein synthesis. Furthermore, the rates of synthesis between 8 and 24 h were enhanced by the addition of cycloheximide. The rates were not further increased by increasing the period of cycloheximide exposure at 37°C, and were actually reduced when cells were exposed to cycloheximide for one hour at 37°C followed by 2 h exposure at 30°C. These data suggest that a temperature dependent event not involving protein synthesis, occurs early in the production phase and influences the rate and duration of interferon (IFN) synthesis. The data also show that although temperature manipulations can be used to enhance IFN yields, the extent to which one can prolong the period of IFN production is limited by a decreasing rate of cellular metabolism.