Autoimmune T cells retard the loss of function in injured rat optic nerves

We recently demonstrated that autoimmune T cells protect neurons from secon dary degeneration after central nervous system (CNS) axotomy in rats. Here we show, using both morphological and electrophysiological analyses, that t he neuroprotection is long-lasting and is manifested functionally. After pa rtial crush injury of the rat optic nerve, systemic injection of autoimmune T cells specific to myelin basic protein significantly diminished the loss of retinal ganglion cells and conducting axons, and significantly retarded the loss of the visual response evoked by light stimulation. These results support our challenge to the traditional concept of autoimmunity as always harmful, and suggest that in certain situations T cell autoimmunity may ac tually be beneficial. It might be possible to employ T cell intervention to slow down functional loss in the injured CNS. (C) 2000 Published by Elsevi er Science B.V. All rights reserved.