Nerve growth factor (NGF) is synthesized as a precursor (proNGF) which may be released and have physiological functions to cause cell death. It binds neurotrophin receptor p75 and sortilin and may also be important for the development of nervous system. proNGF is synthesized in target tissues and glia, transported retrogradely and may be released. This antibody is raised in sheep to detect the prodomain of NGF not the mature peptide.