I've just started working with the U-937 cell line (ATCC CRL-1593) and I'm having some problems.
I thawed and seeded a new vial of cells that came directly from ATCC. I'm using RPMI + 10% FBS like they recommend. The problem is that the cells are growing like crazy. Yesterday, I split the cells, 1:2000, 10 ul cells in 20 ml medium, 2*10^5 cells/ml. Today the medium is completely yellow and the culture is overgrown.
The cells are very small, but they look alive. It doesn't look like there's any contamination. What's going on?
Any experience with this cell line would be greatly appreciated. What the cells are supposed to look like etc. How fast they divide etc. If it's common for the medium to turn yellow.