|T cells which secrete interleukins|
Numbers that start with T and F are secreted by T cells.
Two, Three, Four, Five, Ten.
IL-2, IL-3 are secreted by all T cells.
IL-4, IL-5, IL-10 are predominantly secreted by TH2 cells.
So what do TH1 cells secrete? IFN-Y.
If you flatten the arms of Y it does look like a T and it's also got a F!
Hope it makes your life (a little) simpler! =)