Stable Transfection of CEM cells - (Jan/10/2002 )

I'm trying to stably transfect CEM cells with the pCI-neo vector (Promega) using Promega's TransFast reagent.  I'm only getting very minute levels of expression in transition studies and have been unable to generate any stable transfectants.  I would appreciate any advice.

Increase the drug concentration gradually, it means start with 100ug/ml initally, and increase to 200 after one weekand go on, it may helpfull to select stable transfectants.