LPS won't induce IFN-g secretion as IFN-g is a T cell cytokine and LPS activates myeloid cells. ConA works better for murine cells. We use PHA-P for human cells. I am assuming that PHA-L (or PHA for that matter) would work the same. Just add 1-20 ug/mL PHA to your PBMC culture and leave them for 1-2 days at 37C. We have noticed that it works better when cells (10e6/mL in RPMI-10% FBS) are plated in 5 mL polypropylene tubes (compared to plates). Spin the cells down, collect the supernatants and perform IFN-g/Rantes ELISA.

Thank you Julie Joseph for your answer.