I want to test functionality of the secreted cytokines in the supernatant of my transfected cells for the IL-18 and IFN-gamma, that means not just their presence which can done by ELISA, PCR or WB, but by a functional assay measure the cellular response to their signal, which like measuring the cellular pathway they are activating. Is there any ready to use kit available or cell line tagged with GFP for example?