Recently, I want to modified the T cells with eGFP regulated by the NFAT signalling. And the attached is the map of the lentivirus plasmid. 

However, there is no fluorescence in T cells activated by CD3 mab for 24hs after transfered with the NFAT-GFP.

So where's the problem? The structure of the plasmid or the method of T cell activation?