Figure 2. Proliferation of total CD3+ T cells after treatment with MENK. The cells were cultured with MENK for 7 d in vitro and cell numbers were measured by FCM. The cells grew into distinguished percentage. Especially the collected data indicated that CD4+T cells, CD8+T cells (Fig. 3), and NK cells (Fig. 4) were increased significantly, which were predominantly cell types for anti tumor activity were the cells of innate immune system. So these proved that MENK exerted a broad effect on the cells in both innate immune system and adaptive immune system and provided direct evidence of interaction between neuropeptide and immune system.