Coordinator:  Sabine Suppmann
Head Recombinant Protein Production
Biochemistry Core Facility
Max-Planck-Institute of Biochemistry
Am Klopferspitz 18| 82151 Martinsried| Germany
phone: +49 8578 2589
mail: suppmann@biochem.mpg.de
web: www.biochem.mpg.de

Members of the P4EU network use diverse eucaryotic host organisms for recombinant protein production. A survey conducted in order to design a benchmarking study on protein expression in eucaryotic hosts showed major interest in Baculovirus and transient HEK293 expression systems:

The rationale of this benchmarking study was to compare the performance of the protocols used in different protein production facilities for expression of a common set of target proteins. Different target proteins were chosen for expression in insect and HEK293 cells, as the aim of the study was not to compare insect vs HEK293 expression, but to identify the most successful protocols from both expression systems. The comparison of overall protocols, with their many variable parameters made it difficult to pin-point the individual parameter/s crucial for high performance although trends appeared to suggest the importance of certain parameters that can easily be investigated further in follow-up experiments. A positive aspect of this study was that the best performing protocol(s) were identified and can be used as a guide by those colleagues who experience problems, or are setting up a new insect cell platform, to navigate them through the many decisions that have to be made.

The genes chosen for insect cell expression were provided as pFastBac and pFlashBac constructs:
• four intracellular proteins, with previously observed expression levels of < 1mg/L, and with sizes ranging from 68 kDa to 204 kDa.
• two secreted proteins, with previously observed expression levels of 0.5 and 10 mg/L, and with sizes ranging from 19kDa to 61 kDa.

• The genes chosen for HEK293 expression included
  • four secreted proteins, with previously observed expression levels of 0,1 to 10 mg / L and with sizes ranging from 20 kDa to 75 kDa.
  • two intracellular proteins, with previously observed expression levels of 0,4 and 1 mg / L, with sizes of 68kDa and 124 kDa
• .Participation in the study
  • seven labs expressed six insect targets using the pFastBac system.
  • seven labs expressed six insect targets using the pFlashBac system.
  • seven labs expressed six targets in HEK293 cells.
• Results of the study
  In the HEK data set, productivity in the majority of labs was very similar with two exceptions. Unfortunately, there was no obvious link between productivity of these two groups and the protocols used, so the HEK exercise proved inconclusive.The results of the baculovirus mediated protein expression in insect cells were very conclusive and supplemented with a follow-up study. All results are published in the Journal of Structural Biology https://doi.org/10.1016/j.jsb.2018.03.04