There are several methods to measure cytokine levels in your cell culture supernatants.  First I would check for ELISA kits which are commercially available for this purpose.  Are you looking in human, mouse or other species cell lines?  Some cytokines are species specific.  If you do not have access to the commercially available ELISA kits, there are also some bioassays available for TGFB (Mink lung cells; Mv1Lu) and LIF (M1 cells).  See attached document for general bioassay overview.

I am looking in human cell lines

thank you !

We use ELISA to measure various cytokines levels in cell culture media.

If you are looking for a wide analisys, perhaps you wil be interested in bioplex

My attachment also included cells for bioassays for human cytokines.  Also, ELISA kits are available for many human cytokines and simple to run

thanks alot :)

You can use Cytometric Bead Array (CBA) which is multiplexed bead-based immunoassays and detect multiple cytokines at a time with flowcytometer.