Tips from the American Journal of...(University Hospital Zrich in Zrich Switz...),Health

Demylination and axonal damage cause the cognitive and motor symptoms of MS. Although the immune system, in particular CD8+ T cells, contributes to this axonal damage, it remains unclear whether this damage results from direct attack of the axons or as an indirect byproduct (collateral bystander damage).

Sobottka et al used a live continuous confocal imaging approach to examine the role of CD8+ T cells in experimental autoimmune encephalitis (EAE), a mouse model of MS. They found that CD8+ T cells damaged myelinated axons, even when the stimulatory antigen was expressed inside but not on the surface of nearby oligodendrocytes, which produce the myelin that protects the axons from damage. Thus, axonal loss can be the result of "collateral bystander damage," and new treatments should be developed with a focus on the CD8+ T cell/oligodendrocyte interface.

Dr. Goebels and colleagues "are confident that [these] findings critically contribute to the understanding of CD8-mediated neuropathology in CNS inflammation, strengthen a pathogenic role of CD8+ T cells in MS and advocate for the development of future immunotherapies aiming at the CD8-myelin/oligodendrocyte interface."

Sobottka B, Harrer MD, Ziegler U, Fischer K, Hnig T, Becher B, Goebels N: Collateral bystander damage by myelin-directed CD8+ T cells causes axonal loss. Am J Pathol 2009, 175: 1160-1166

'/>"/>