Postnatal development of a demyelinating disease in avian spinal cord chimeras.

Xenogeneic spinal cord chimeras were constructed by grafting fragments of quail neural primordium into chick embryos at 2 days of incubation. Hatched birds displayed normal motor behavior for about 5 to 7 weeks, whereupon they developed a neurological syndrome; in the grafted spinal cord the pathological signs of the disease were very similar to those of the active plaques of multiple sclerosis and of the lesions of experimental allergic encephalomyelitis and neuritis, including Ia expression by brain capillary endothelia, rupture of the blood-brain barrier, leukocytic infiltration in the nervous tissue, and demyelination. In the animals at the most advanced stage of the disease an autoimmune attack occurred on the host's nervous system with the same histopathological signs.