Peripheral blood mononuclear cells
IL-2 is necessary for the growth, proliferation, and differentiation of T lymphocytes to become functional T cells.122 Antigen binding to the T-cell receptor stimulates the secretion of IL-2 by T cells and the expression of IL-2 receptors (IL-2Rs). The IL-2/IL-2R interaction stimulates the growth, differentiation, and survival of antigen-specific CD4+ and CD8+ T cells. IL-2 plays an important role for the development of T-cell-dependent immune memory. An in vitro study reported the effects of LBPs on the expression of IL-2 and TNF-α in human peripheral blood mononuclear cells (PBMCs) from healthy volunteers.130 The LBPs used in this study were the third fraction of LBPs extracted with hot water from L. barbarum planted in Zhongning, Ningxia, People’s Republic of China and isolated by anionic exchange chromatography and gel-filtration chromatography. Administration of 10 mg/L LBPs increased the expression of IL-2 and TNF-α at both mRNA and protein levels in a dose-dependent manner. Treatment of human PBMCs with 5 mg/L, 10 mg/L, 20 mg/L, and 40 mg/L LBPs increased IL-2 mRNA 1.8-, 3.9-, 7.0-, and 7.4-fold, respectively. The activity of IL-2 was increased 4.3-, 7.7-, 14.2-, and 16.0-fold, respectively, compared to the negative control.130 Treatment of PBMCs with 5 mg/L, 10 mg/L, 20 mg/L, and 40 mg/L LBPs increased TNF-α mRNA level 2.4-, 3.9-, 6.1-, and 15.4-fold, respectively. The activity of TNF-α after treatment with 5 mg/L, 10 mg/L, 20 mg/L, and 40 mg/L LBPs for 8 hours was increased 7.1-, 9.1-, 13.6-, and 15.2-fold, respectively, compared to the negative control. LBPs may induce immune responses that contribute to the therapeutic effect in cancer.