DIFFERENTIATION EFFECTS OF CILIARY NEUROTROPHIC FACTOR ON HUMAN NEUROBLASTOMA-CELLS

In the human neuroblastoma cell line LA-N-2, recombinant rat ciliary n eurotrophic factor (CNTF) induced neurite growth and cholinergic diffe rentiation that were both half-maximally saturated at <100 pM of the n eurokine, but was not required for cell survival in serum-free conditi ons over a 13-day period. CNTF markedly stimulated choline acetyltrans ferase activity and acetylcholine synthesis, whereas high-affinity cho line transport was only slightly enhanced and acetylcholinesterase act ivity was unchanged. Leukemia inhibitory factor had effects identical to CNTF on neurite growth and choline acetyltransferase activity, but interleukin 6 had no effect. Radioiodinated CNTF binding and affinity cross-linking studies were consistent with tripartite receptor activat ion as a mediator of the observed biological effects.