NERVE GROWTH-FACTOR FROM THE VENOM OF THE CHINESE COBRA NAJA-NAJA-ATRA - PURIFICATION AND DESCRIPTION OF NONNEURONAL ACTIVITIES

Nerve growth factor (NGF) was separated from crude Naja naja atra veno m by using weak cation-exchange chromatography, followed by reversed-p hase liquid chromatography. The yield of the purification was 0.2-0.5% (w/w). The mel. wt was determined to be 13,600 and the protein still induced the typical fibre outgrowth of cultured PC-12 cells in a conce ntration range of 5-10 ng/ml. Beside this neuronal effect we demonstra ted non-neuronal effects of cobra venom NGF, such as induction of plas ma extravasation and histamine release from whole blood cells. With hu man leucocyte preparations, including enriched basophils, there was an increase in C5a-induced histamine release, whereas NGF alone was inac tive. Cobra NGF was one-tenth as potent as human recombinant NGF, with a half-maximal stimulation occurring at 10ng/ml. Cobra NGF and human recombinant NGF showed a modulatory effect on histamine release compar able to the haematopoietic growth factor IL-3. Thus, the non-neuronal effects of cobra NGF may account for immunomodulatory activities durin g inflammatory events.