Increased Transendothelial Transport of CCL3 Is Insufficient to Drive Immune Cell Transmigration through the Blood–Brain Barrier under Inflammatory Conditions In Vitro

Figure 3

Basolateral-to-apical transport of exogenous CCL3 across the BBB in vitro is increased under inflammatory conditions but is not affected by preincubation of BBB cocultures with blocking antibodies targeting CCR1 or CCR5, suggesting that these chemokine receptors are not involved in the transendothelial transport of CCL3. To discriminate between active transendothelial transport, which takes place at 37°C only, and passive paracellular leakage of exogenously added CCL3 occurring at both 4°C and 37°C, experiments were performed at both 37°C and 4°C (, ; ; ).