Adaptation of insect cells to suspension culture

Abstract

An assessment was made of the effects of successive passages, the concentration of fetal calf serum, and the presence of methyl cellulose and pluronic F-68 on the adaptation of Spodoptera frugiperda and Trichoplusia ni cells from stationary to suspension growth in shake flasks and an external loop airlift bioreactor. The studies showed that it takes about six successive passages to adapt Spodoptera frugiperda cells to suspension growth in shake flasks. The population doubling time was about 35 h with a maximum cell density of 5 × 10 6 cells/ml. In comparison, pour cell growth was observed for Trichoplusia ni cells in shake flasks. The presence of a higher serum concentration, methyl cellulose, and pluronic, while beneficial for cell growth, was not as important as the passage number. Preliminary experiments with an external loop airlift bioreactor suggest that Spodoptera frugiperda insect cells, previously adapted to shake-flasks, cannot survive air-sparging if the bubble diameter is less than 500 μm.