Improved process conditions for increasing expression of MHC class II protein from a stable Drosophila S2 cell line.

Objectives: To investigate the effects of operational process conditions on expression of MHC class II protein from a stable Drosophila S2 cell line.

Results: When the Drosophila S2 cells were grown in vented orbitally shaken TubeSpin bioreactor 600 containers, cell growth was improved three-fold and the yield of recombinant major histocompatibility (MHC) class II protein (HLA-DR1) increased four-fold over the levels observed for the same cells cultivated in roller bottles (RB) without vented caps. Culturing in RB with vented caps while increasing the rotation speed from 6 rpm to 18 rpm also improved cell growth five-fold and protein productivity three-fold which is comparable to the levels observed in the orbitally shaken containers. Protein activity was found to be almost identical between the two vessel systems tested.

Conclusions: Optimized cell culture conditions and a more efficient vessel type can enhance gas transfer and mixing and lead to substantial improvement of recombinant product yields from S2 cells.