TRANSGENIC MICE FOR INTERLEUKIN-3 DEVELOP MOTOR-NEURON DEGENERATION ASSOCIATED WITH AUTOIMMUNE REACTION AGAINST SPINAL-CORD MOTOR-NEURONS

Interleukin 3 (IL-3) stimulates the proliferation and differentiation of various haematopoietic progenitor cells. Recently, IL-3 and other c ytokines were reported to exert a neurotrophic activity and to be asso ciated with neurological disorders, suggesting their complex role in t he central nervous system. We now show that overexpression of IL-3 in transgenic mice causes a motor neuron disease with several features of amyotrophic lateral sclerosis and progressive muscular atrophy. These animals exhibit hind limb paralysis at 7 months of age, associated wi th dendritic and axonal degeneration, loss of motor neurons in the spi nal cord, and autoimmune reaction against these cells. We examined the effect of IL-3 on embryonic motor neurons survival in mixed spinal co rd cultures. Our results suggest that motor neuronal degeneration is n ot directly triggered by the high level of expression of IL-3.