Using allogenic co-culture system, we further show that lymphoma cells augment the expression of PD-1 on T cells, decrease the proliferation of T cells, decrease the secretion of interleukin-2 (IL-2), interferon-gamma (IFN-γ), tumor necrosis factor-alpha (TNF-α), and IL-10 in the supernatant of co-culture. Here, IL2 is linked to lymphoma.