IL2 and neoplasm: To clarify whether the enhancement of tumor cell lysis by the novel tribodies was combined with increased secretion of cytokines by lymphocytes, the concentration of interferon γ (IFNγ) and interleukin-2 (IL-2), functional markers for hPBMC activation [37, 38], released in the culture supernatants of those co-cultures was measured, and the effect of the novel tribodies was compared with the effect of 53 P in combination with each of the mAbs in clinical use.