Enhancement of CNS infiltration of CD4⁺ T cells and expression of VCAM-1 following cessation of BIO 5192 treatment. Sections of the lower thoracic spinal cord from representative animals described in Figure 2 were stained for infiltration of CD4⁺ T cells and for VCAM-1 expression after 22 treatments (day 39 after priming—on treatment) and 5 days after treatment was terminated (day 44 after priming—off treatment). DAPI, in blue, stains all cells; CD4⁺ cells and VCAM-1 expression are marked in red. (A) Day-39 spinal cord CD4⁺ infiltrate in a vehicle-treated animal. (B) Day-39 spinal cord CD4⁺ infiltrate in a BIO 5192-treated animal. (C) Day-44 spinal cord CD4⁺ infiltrate in a vehicle-treated animal. (D) Day-44 spinal cord CD4⁺ infiltrate in a BIO 5192-treated animal. (E) Day-44 spinal cord VCAM-1 expression in a vehicle-treated animal. (D) Day-44 spinal cord VCAM-1 expression in a BIO-5192 animal. All sections are 6-μM thick with original magnification, × 100.