Interleukin-4 (IL-4), produced primarily by CD4(+) T cells is an immunomodulatory cytokine, which can inhibit the growth of tumour cells. IL-4 has been known as a Th2 cytokine and can act on B cells, T cells, and monocytes. IL-4 has an antitumor activity in rodent experimental gliomas, which is likely mediated by the actions of IL-4 on a variety of immune cells present in and around the tumor masses. Recombinant Human IL-4 produced in E. coli is a single non-glycosylated polypeptide chain containing 130 amino acids with a MW of 15,000 Da.