The Sf21 cell line is a suitable host for transient or stable expression of recombinant proteins using baculovirus expression vectors, propagation of baculovirus stocks, and plaque assays to accurately determine AcMNPV virus titre. They are also ideal for monitoring cytopathic effects and are more tolerant to sub-optimal growth conditions. The insect cells are adapted to growth in serum-containing medium such as TC-100 supplemented with 10% FBS. They can easily be cultured as monolayer cultures in T-flasks or in stirred culture flasks.