Problems with B-cell line BJAB - clumps formed by cells in culture (Nov/03/2004 )

Hi!
I have some problems with a Burkitt's lymphoma cell line called BJAB....I'm maintaining the cells in standard normal conditions (RPMI, 10% FCS, L-glutamine, Pen/Strep antibiotics, Sodium Pyruvate), in flasks without shaking....
Some days ago I noted the formation of cell clumps that are very difficult to eliminate by pipetting or shaking (this clumps render tht counting of the cells very hard!!!...)....At the beginning of this phenomenon the cells grew well but I observed that the medium quickly became yellow.....and now, the cells do not grow as well as before.....
In parallel, I'm maintaining other B-cell lines that grow well, do not form these clumps, and the medium does not change the color as BJAB cells...
Is here someone that could explain me this phenomenon, and could help me to solve this problem?...Someone suggested me to add heparin....is it a good idea?

Thanks a lot!!!
Stefania

I think a yellow color in your cell media is indicative of a bacterial infection.
Is it cloudy as well?