Extraction of peripheral blood derived macrophages

[P.M. Newton]

Hello
I am attempting to extract peripheral blood monocytes and then differentiate 
them into macrophages, maintaining the cells as macrophages in culture for as 
long as poss.
I have reliable protocols for the ficoll extraction proceedure, and can get 
good yields of monocytes, but these remain attached to the tissue culture 
plastic for a maximum of 48 hours before floating off, which is no good to me 
(i need at least a week).
Can anyone offer any tips on how to keep the cells adherent and 
differentiated?
i am aware a dose of M-CSF or GM-CSF may do the trick, but if anyone has any 
other (preferably cheaper!!) suggestions they would be most appreciated.

thanks
Phil Newton 
SBMB 
Uni of Leeds.