ProteoCool Pills#17: Alternative cheaper trasfection agents for recombinant protein/antibody expression with Expi293

 As already reported in the ProteoCool n° 29, Expi293 are a powerfull cell line those, thanks to their ability to growth up to very high cell density and be transfected with high efficiency are able to secrete in the surnatant high yields of recombinant proteins.

The main factor that currently limit the application of this system is certanilly the cost, since the volumetric cost (euro/liter of culture) is very high and comparable with the cost of a 13C/15N labelled sample in E.coli.

Cost of 30ml culture of Expi293 (updated to July 2022)

Components:

a) Expi293 expression medium (cod. A1435101 Thermo)  cost: 331euro (quotation 2022) --> 1 liter 

b) Expifectamine trasfection kit (cod. A14524 Thermo) cost:  1100 euro  (quotation 2022) --> For 1 liter

c) Cup vented Corning shaking flaks 125ml cod. 734-1885 (VWR quotation 2022) --> 8,8 euro/flask

d) DNA preparation  (EZNA mini kit II cod. D6945-02) 1 -> euro/1 sample – Thermo midi kit cod. K210004 cost 4euro/1sample)

Therefore the total cost of a 30ml tranfection 

 9,9(a)+ 33(b)+8,8(c)+1-4(d) = 50-55euro/flask  --> Around  1.800 euro/liter

and the tranfection reagent contribute to more than 50% of the costs (33 out of 55 euro)

Since the Expi293 become progressivelly more popular, several company develope alternative  tranfection agents that are suggested to be suitable for Expi 293.

In this post i briefly sgow you the results that i obtained by comparing;

- The standard Expifectamine 293 Transfection kit ;

- Endofectin Expi293 transfection kit;

- FectroPro transfection kit 

2 different expression trials in 2ml format (6 well plates)

Trial 1: 2 recombinant His-tagger protein; 

Trial2; 2 recombinant monoclonal antibodies)

 performed to compare the  producivity of the different trasferction agents;

In all cases the only reagents that are different are those part of the transfection kits

, while culture media (Expi293 culture media) and antibiotics, are the same 

alteady listed in ProteoCool n°29

Summary:

Those preliminary data suggest that both Endofectin Expi293 and Fectopro

 show performances close to the Expifectamin293  Thermo reagent with Expi293 cells

Of course the trails was performed with a limited number of protens and few replicates and more data need to be performed to confirm it, but it seems that the differences in protein/antibody productivity, if there are differences, are much less important than the difference in terms of costs.

The same comparision performed with the Expi-CHO kit was not successfull (data not shown) 

probably because the Endofectamine293 and Fectopro Kit do not contain any medium Feed

 which seems to be essential to allow the ExpiCHO cells to growth until high cell densities

  (trasfection with ExpiCHO is performed at 6*10^6 cells/ml vs 3*10^6 cells/ml used for the Expi293) and retain good viability during the entire trasfection(8 days).