IL34, also known as Interleukin 34, is a protein belonging to a group of cytokines called interleukins. This protein increases growth or survival of immune cells known as monocytes; it elicits its activity by binding the Colony stimulating factor 1 receptor. It also has a potential role in viral infection, the adaptive immune response and bone marrow cell proliferation. Recombinant human IL34 protein, fused to His-tag at N-terminus, was expressed in E.coli.