PRODUCTION OF TERMINALLY DIFFERENTIATED NEUROBLASTOMA-CELLS IN CULTURE

The use of fetal central nervous system (CNS) tissue in neural transpl ants has ethical, availability and some biological limitations. In ord er to overcome these problems, homogeneous populations of specific neu rons in vitro should be established. Transformed nerve cells such as n euroblastoma cells (NBP2) in culture can serve as one of the sources o f donor neurons in neural transplants provided they can be induced to differentiate terminally. This study showed that treatment of murine n euroblastoma (NBP,) cells with 4-(3-butoxy-4-methoxybenzyl)-2-imidazol idinone (R020-1724, an inhibitor of cyclic nucleotide phosphodiesteras e), and beta-carotene for a period of 3 days followed by X-irradiation with 20 Gy or above produced 100% terminally differentiated cells. Th ese differentiated NB cells had long and extensive neurites, contained elevated levels of tyrosine hydroxylase (TH) activity and very low le vels of MHC class I and II antigens, and were non-tumorigenic. The via bility of differentiated NB cells when determined on the criteria of a ttachment efficiency, re-extension of neurites and presence of TH afte r replating was only 9%. This was in contrast to the trypan blue exclu sion technique which showed that over 90% of differentiated NB cells i n culture were viable.