CX3CL1 expression in the brain during EAE progression. (A) Brain CX3CL1 expression of wild type mice with EAE as determined by quantitative real-time PCR. Gene levels were normalized to GAPDH levels and are displayed as levels relative to naïve mice. Error bars represent the s.e.m. (n = 5 mice per group). (B-M) Brains from naïve wild type mice were harvested and frozen for immunostaining. CX3CL1 expression (red) and DAPI nuclei staining (blue) in (B, F, J) naïve and (C, G, K) Day 10, (D, H, L) Day 14, and (E, I, M) Day 21 post-EAE induced wild type mice. CX3CL1 expression is displayed at the (B-E) choroid plexus, (F-I) in and near the hippocampus, and (J-M) cerebellum. White scale bars represent 50 μm. (N) CX3CL1 expression (relative to non-treated cells) in the CPLacZ-2 mouse choroid plexus cell line after 2 hour treatment with varying concentrations of the A2A adenosine receptor specific adenosine receptor agonist CGS21680. Error bars represent the s.e.m. (O) Lymphocyte migration across a transwell choroid plexus barrier following pretreatment with vehicle treatment alone, CGS21680, or CGS21680 and anti-CX3CL1. Total migration was normalized to the vehicle control (set to 100%). Error bars represent the s.e.m. These results are representative of two separate experiments (n ≤ 3).