Quantification of CCL5-driven PBMC migration across basal IVBBB and aIVBBB. Parallel transmigration assays across either the basal IVBBB or aIVBBB, with or without 100 ng/mL CCL5 were performed using calcein-AM labeled and unlabeled cells as described in the Materials and Methods section. There was preferential migration of CD14+ monocytes across either IVBBB models, with higher levels seen across the aIVBBB. There was CCR5 up-regulation on monocytes during the transmigration assay (based on increased numbers and percentages of CD14+ CCR5+ cells in the non-migrated and migrated populations without added CCL5, relative to the input), with receptor down-regulation (based on reduced numbers and percentages of CD14+ CCR5+ monocytes) following CCL5-induced migration. CCL5 facilitated an increase in total CD3+ T-cell migration across either IVBBB models that was more efficient for CCR5+ cells (based on the higher percentages of migrating CD3+CCR5+ T-cells relative to the input and cells migrating without added chemokine). Higher numbers of migrating CD3+ T-cells were seen with the aIVBBB, indicating that endothelial activation significantly induced chemokine-driven T-cell migration in vitro. Shown are the means of five separate experiments using different donors. [ ] indicates the mean percentage of input cells that migrated in 3 hours, while ( ) indicates the mean percentages of the parent mononuclear cell population that were CCR5+. Key: aIVBBB: cytokine-activated in vitro blood-brain barrier, IVBBB: in vitro blood-brain barrier, PBMCs: peripheral blood mononuclear cells.