IL2 and neoplasm: IL-2, a Th1 cytokine, stimulates the growth and proliferation of T and B cells, activates T cells to secrete IFN, enhances the cytotoxic activity of natural killer cells and macrophages, and induces the anti-tumor and anti-infection activity of tumor-infiltrating lymphocytes, primarily exerting cell-mediated immune functions (Zeng et al., 2010).