CHRONOLOGICAL LOCALIZATION OF MYELIN-REACTIVE CELLS IN THE LESIONS OFRELAPSING EAE - IMPLICATIONS FOR THE STUDY OF MULTIPLE-SCLEROSIS

Although T cells play a pathogenetic role in MS, specific disease-indu cing T cells have not been identified. T cells can be labeled and trac ed in adoptively transferred experimental autoimmune encephalomyelitis (EAE), a T-cell-mediated animal model for MS. We have followed the ap pearance and topographic localization of radiolabeled myelin basic pro tein-reactive (MBP+) T cells in evolving lesions as EAE extended to ot her regions of the CNS. By high-resolution autoradiography, we confirm ed that MBP+ cells initially homed to perivascular regions in the lowe r spinal cord. With increasing time after cell transfer, labeled cells appeared in more recent lesions in rostral locations (upper spinal co rd, cerebellum, and forebrain) and constituted a progressively smaller percentage of cells in lower spinal cord lesions. The presence of unl abeled inflammatory cells in the CNS parenchyma coincided temporally w ith clinical signs. In agreement with previous studies, we have shown that MBP+ cells constituted a minority (mean, <1.5%) of the total infi ltrating cells and were most numerous in fresh lesions. We suggest tha t the perivascular regions of recent lesions would be the most likely areas to detect putative antigen-specific cells in MS lesions.