Hi everybody, can you help me?

I am seeding mouse spleen cells 2/3 days with Dynabeads CD3/CD28 activator and IL2 to stimulate the production of perforin and granzyme B. I'm then doing a cytofluorimeter and there's nothing, literally! Tried also with immunofluorescence but nothing.

What am I doing wrong? Should I leave the spleen more with activators? Or the situation is not enough strong for their expression?

Thank You in advance