The effect of trypsin on the growth of rotavirus.

It has been found that 1000-fold more bovine rotavirus is obtained when trypsin is incorporated in the maintenance medium and allowed to remain throughout the growth cycle. This holds true for primary calf kidney (CK) cells and also for several continuous and semi-continuous cell lines. In the presence of trypsin it has been possible to pass the virus serially on continuous cell lines seven times. Concentrations of 1 to 10 microgram/ml of trypsin are found to be effective. Preliminary results suggest that the same technique will be effective for the in vitro propagation of human rotavirus.