Antigenic cross-reactivity of nerve growth factors from diverse source: activity versus toxicity of NGF

NGF used in these studies was from various sources: cobra venom (V-NGF), mouse submaxillary glands (M-NGF), honeybee venom (B-NGF), human serum (H-NGF), and cobra serum (CS-NGF). This investigation reports the antigenic cross-reactivity of NGFs from the above mentioned diverse sources. Antigenic cross-reactivity of NGFs was determined by immunological test, using anti-NGFs against V-NGF, M-NGF, B-NGF, and H-NGF. Results revealed that NGF was a conserved protein showing antigenic cross-reactivity among the NGFs from diverse source, except for NGFs from cobra and bee venoms. Anti B-NGF reacted poorly with cobra venom V-NGF and vice versa. Anti M-NGF showed higher antigenic reactivity with human serum H-NGF than with honeybee B-NGF and cobra serum CS-NGF. This research also reports that the toxicity of NGF is directly related to the biological activity of producing neurite outgrowth on PC12 cells. Cobra venom NGF produced neurites at 1-5 ng, and it was toxic at 10-20 ng on PC12 cells. After reducing the activity of NGF, it was found to be non-toxic to PC12 cells at 50 X concentration.