Ciliary neurotrophic factor (CNTF), also known as membrane-associated neurotransmitter stimulating factor (MANS), is a potent neural factor that was initially purified from chick embryo ocular tissue. In terms of neuronal specificity CNTF overlaps with neurotrophins, although its cellular localisation, receptor structure, and signaling pathway are distinct from those of the neurotrophin family. The CNTFα receptor has been localized to skeletal muscles and to the nervous system. One receptor subunit is known as gp130 which is also a component of receptors for the leukaemia inhibitory factor (LIF), interleukin 6 (IL-6), interleukin 11 (IL-11), and oncostatin M (OSM). CNTF is present in normal peripheral nerves, localised mainly in the cytoplasm of myelin-associated Schwann cells as well as astrocytes in the central nervous system. It promotes the survival of neurons and oligodendrocytes as well as sensory neurons, motor neurons, basal forebrain neurons, and type 2 astrocytes. CNTF is highly conserved across species and exhibits cross-species activity.