CNTF also known as ciliary neurotrphic factor is a survival factor for various neuronal cell types. CNTF is highly conserved across species and exhibits cross-species bioactivity. CNTF is a 25 kDa polypeptide that was originally isolated as a target-derived survival factor of parasympathetic ciliary ganglion neurons. Binding of CNTF to CNTF receptor triggers heterodimerization of gp130 and LIFR, forming an active trimeric receptor complex and activates the downstream signaling pathway. Recombinant rat CNTF, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography techniques.