I am currently working with COS-7 cells. I have noticed recently that every time I passage them, I find a lot of dead cells 2 days later. I use DMEM with 10% FBS and trypsinize them for 5 minutes in the incubator and am culturing them in a T-75 flask. I have not seen any bacteria or yeast but will be testing for mycoplasma. I am not sure what else could be affecting them/if this is normal.
Anything would be helpful!
Thanks :)
Hello Zainab
I too have experienced the same. COS-7 cell culture shows cell debris in culture. If you are going to use COS-7 cells for transfection experiments use cells of low passage number because cells with high passage number will show genotypic variation and may become slow growing and hard to transfect.
Have you tried culturing the cells in a smaller T-25 flask ?
Regards.
Malcolm Nobre Hi Malcolm,
Thank you for your response, they are currently at P10 and I have been able to transfect. What passage number have you seen the growth start to decline? I was initially culturing them in T-25 flasks but switched when I was starting to make frozen stocks. I haven’t tried since this has started, perhaps I can split them back into T-25 and see if I observe the same. I didn’t think it would affect them as much. I wasn’t sure if what I am seeing is normal or if I should thaw a new vial of cells.
Hi Zainab
In my case these cells started showing changes at P32. I had to thaw a new vial for my experiments at P6.
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