My lab is working with a novel CHO cell line adapted from CHO-K1. We would like to use it for production however, its culture lengths are 20+ days. We tried to reduce culture length by starting with a higher seeding density but only got limited success (on average decreased from D21 to D17). Depleting the cells of glucose and feeds also has had a minimal impact on culture length, I guess the cells are pretty hardy.
We are hoping to get our culture length down to 13 days.
What other methods are out their for reducing culture length? Has anyone worked with cells with similar characteristics before?
Have you grown cells in fermentors? shake flasks? Were you able to control pH? Did you try to use growth factors, such as insulin-like growth factor -1, in the medium?
We are currently doing most of our experimentation in shake flasks. We have run wave reactors with the high seeding density condition that also lasts till D17. We are running our first stir tank 3L now.
Our pH has always been an issue too. In a non optimized process, on day 0 pH=7, day 3 pH=6.8, and from then on it maintains at 6.6. This process runs till D17. When we fixed the pH issue through glucose limitation, our cultures started lasting to D21.
In the past we havent seen much impact on productivity or culture characteristics by adding insulin, however that could be an avenue worth exploring. Does it arrest cell growth?
Use high quality sera,medium to a volume maxium allowable for the shake culture and also increasing the number of lesser volume flasks than use of a single high volume flasks are strategies I will try out in your situation.
Good luck with your expt.
Biju Joseph
We are developing a process for bioproduction, we cannot use serum containing medias.
I am not experience in this but I read something about lysophosphatidic acid LPA compensating for serum? Is it worth trying in the media? Also something about maintaining pH around 6.9 for CHO cells. Since you haven't looked at IGF-1, may be worth looking.
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