? Definition of Passage for suspension cells - (Apr/16/2009 )

Hi all

A fairly simple question I suppose but I am new to this.

What is the definition of a passage for a suspension cell line? For adherent cells it would be fairly straight forward ie everytime you trypsinize and reseed a new flask, but what about suspension cells ( in my case THP-1). Is it everytime you reseed a new flask, everytime you remove say 2/3 volume and add fresh media, everytime you add fresh media or all of the above?

Thanks in advance

Dale

It is every time you remove some of the cells and add fresh media. Ideally, you would be looking at population doubling times while you are doing this, so as to have a better idea of when to passage.