Th1 cells from the Tg mice listed were isolated and transferred into irradiated HLA-DRB1*0401–IA^−/− Tg mice. The EAE score and percentage of weight loss are listed for 13 animals which were examined histologically. For comparative purposes, a visual grading scheme was assigned to the lesions in each of the animals examined. The histological score of inflammatory lesions is as follows: +, occasional inflammatory cell cuffing in meninges; ++, mild lesions in a few sections (<50%); +++, mild or moderate lesions in many sections (>50%); ++++, severe or moderate changes in a few sections (<50%); +++++, severe or moderate changes in many sections (>50%). Necrosis and axonal degeneration were observed in most lesions of grade 4 to 5 (++++ → +++++) severity. Demyelination, as observed in Luxol Fast blue–stained slides, was seen in the spinal cord and brainstem in 6 of 12 mice examined.