The target cells of IL-7 are mainly lymphocytes, and have growth-promoting activities against B progenitor cells derived from human or mouse bone marrow, thymocytes, and peripheral mature T cells. Synergistic with stem cell growth factor (SCF) can stimulate mitosis of b precursor, which can be inhibited by tgf and inhibited; but has no significant effect on the growth of progenitor B (pro-b). Promote the maturation of double-negative thymocytes, and provide the initial signal of tcr gene recombination during embryonic thymocyte development; however, it has no obvious effect on mature T cells. Inducing thymocytes or peripheral blood lymphocytes to produce LAK cell activity, the effector cells are mainly CD8+ subpopulations; however, IL-7-induced LAK cells do not have NK activity.IL-7 can stimulate myeloid precursor cells and megakaryocytes to produce colony forming units and platelets, which can restore the body from the immunosuppressive effect of cyclophosphamide; at higher concentrations, IL-7 can also enhance macrophages. Cytotoxic activity, induces monocyte secretion of cytokines.