PRODUCTION INVITRO OF A NEUROTROPIC SUBSTANCE FROM PROLIFERATIVE NEUROLEMMA-LIKE CELLS

The objective of this study was to better define the biological and chemical properties of a neurotropic substance capable of mediating recognition between neurolemma-like cells and neurites during growth. Using in vitro methods, we showed that it was a macromolecular protein apparently synthesized by proliferative cells and was responsible for attracting and promoting neurite outgrowth from chick embryo dorsal root ganglia. The substance appeared to be a normal component of the cell coat during the proliferative phase, and was secreted into the tissue culture medium. Fractionation of the culture fluid by gel filtration chromatography yielded three major fractions containing the biologically active component. The fraction that had the greatest nerve-growth-stimulating activity appeared in a small molecular fraction (mol. wt., 10,000 to 20,000), and was biologically similar to the mouse salivary gland nerve growth factor (NGF). The neurotropic substance appeared to play a central role in promoting and guiding axonal growth during normal development and regeneration of the peripheral nerve. © 1979.