Our Lab works with induced pluripotent stem cells derived from fibroblasts taken from foreskins. While looking under the microscope on highest mag. I noticed what looked like round vibrating dots that were present between the growing cells. Now I know they are not bacteria due to their large size and lack of swimming movement, however they don't seem to be cell debri either because after a few days in culture they are increased in number.
Now I'm not sure if these are microvesicles budding off the cells or if they are a problem. They don't affect cell growth, media does not change pH and remains clear. See attached video and pictures. My issue is that I still see these present in cells given to us from ATCC which are supposedly contaminant free.
Hopefully someone has experienced the same thing because this is driving me crazy!
Hey there Heather,
While I can't be certain, to me this looks like a lot of dead iPS cells. I hope this isn't your main focal plane for an adherent culture because if it is, clearly something is wrong. Despite the increase in numbers over time, I still think it could be a proliferative culture with high cell death. Perhaps something in your media or your culture conditions are off? Have you recently tested for mycoplasma contamination? Just suggestions of course. If you had an image of the focal plane at the level of the adherent cells I may be able to judge better.
Best of luck!
Cole R. K. Harder
Heather Wanczyk I also think this can be debris from the cell passes. Did you pay attention to the pass number. It is typical to get high amount of debris from relatively large cell pass numbers
Hi Cole, thanks for the response. The first pic with the dead cells happened to be from a vial that was improperly froze down so there were no adherent cells. What i am focusing on are the tiny round white objects between the dead cells. If you look at the attached video you can see how they move
Hi Cole,
It is look like mycobacterium contamination. Infact, there are several reason behind the contamination, such as 1) infected cells supplied by vendors 2) contaminated cell culture medium reagents (serum, trypsin, etc.) infection through laboratory personnel and so on. In that case, I will suggest you to eliminate them if it is not so valuable. Otherwise, you can try to reviving your cells with effective mycoplasma-selective antibiotics. Hope, it may help you to reach the final conclusion.
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