Coupling of nerve growth factor to its receptor: Inhibition by anti-GM(3) ganglioside antibody

1. Normal differentiation of PC 12 cells and dorsal root ganglionic neurons in culture need nerve growth factor (NGF) for their neurite outgrowth. 2. An antibody against GM(3) ganglioside was found to inhibit the nerve growth factor mediated neurite formation of both the cells in vitro significantly . 3. Further analysis revealed that the binding of I-125-NGF to live PC 12 cells could be markedly inhibited by anti-GM(3) antibody in a dose dependen t manner. 4. Scatchard analysis revealed that in the presence of anti-GM(3) antibody only some low affinity binding sites were available for NGF-high affinity binding sites were totally blocked. 5. These results further stren gthen the hypothesis that anti-GM3 antibody affects neuronal cell growth by interfering with the coupling of growth factors to their cell surface rece ptors.