Biological and immunological properties of the nerve growth factor from bovine seminal plasma: Comparison with the properties of mouse nerve growth factor

Abstract

The biological activities of Nerve Growth Factor (NGF) purified from bovine seminal plasma have been compared with those of NGF from mouse submandibular glands in a variety of systems: maintenance of survival in vitro and stimulation of nerve fibre outgrowth from sensory, sympathetic and parasympathetic neurons of the embryonic chick; maintenance of survival in vitro, stimulation of nerve fibre outgrowth and specific induction of tyrosine hydroxylase in neonatal rat sympathetic neurons; stimulation of nerve fibre outgrowth and cellular hypertrophy and specific induction of choline acetyltransferase in pheochromocytoma PC12 cells; induction of tyrosine hydroxylase in bovine adrenal medullary cells; and stimulation of nerve fibre outgrowth from expiants of goldfish retinae. In all cases, the two NGFs had the same effects qualitatively and quantitatively, and with identical dose-dependencies. The results indicate that the wide range of biological effects and target cells delineated in detail for mouse NGF can justifiably be attributed to other NGF proteins, and that they are not exclusively restricted to the mouse NGF molecule. Furthermore, as bovine NGF is free of the renin contaminants so difficult to remove from mouse NGF, the above biological activities can truly be assigned to the NGF molecule. Immunologically, however, mouse and bovine NGFs differ substantially. This is demonstrated by the relatively poor ability of antisera against bovine NGF to inhibit the activity of mouse NGF in vitro, and by the incomplete nature of the immunosympathectomy caused in rats by treatment with antisera to bovine NGF, in contrast to the extensive immunosympathectomy caused in these animals by the administration of comparable quantities of antisera against mouse NGF. Clearly, the biochemical features of the NGF molecules responsible for their biological effectiveness and for their predominant antigenic properties are different.