I met the similar problem that after change the medium it detached. I have induced THP-1 into macrophage for several months. Induction methods is the same as above. Only recently the problems occured. Do you think it is because the cell itself? Because the cells have cultured and passaged for more than three months while induction methods doesn't change.THP-1 cell can passage endless? Please help.Thanks a lot.
Uh, THP-1 cells are a very stable cell line. Passage number does not matter. It has been around since the 1980's. Do you really think that you are getting passage 1 wherever you get them from? Passage number is more an issue for primary cell culture or self-immortalised cells. Just make sure you always keep stocks which are not treated with anything to bring up fresh cells when needed. I have never ever noticed anything change with passage of these cells and must have passaged them hundreds of times. I culture mine in RPMI + 10% FBS and pen/strep. Obviously, over time if you culture cells under certain conditions you may get changes, which is why results can vary from lab to lab, due to different FBS, etc.