Description
IL-4 is a 15-19 kD pleiotropic immune cytokine secreted by activated TH2 cells. It has many biological roles, including the regulation in humoral and adaptive immunity, the inhibition of bone resorption, the stimulation of activated B-cell and T-cell proliferation, and initiation of allergic responses. Moreover, IL-4 induces a positive feedback loop by stimulating differentiation of naive helper T cells, or Th0 cells, to Th2 cells which in turn secrete more IL-4. Increased IL-4 production and overproduction of IL-4R are found in many cancers. IL-4 has a significant effect on tumor progression by increasing apoptosis resistance via tumor growth enhancement. IL-4 may also play a part in the immune dysregulation that occurs in most HIV-1 infected patients