CCL2 and infection: Using real-time PCR, we similarly demonstrated that SS2 strain SC19 infection of hBMEC resulted in a strong production of proinflammatory cytokines and chemokines, including IL-6, IL-8, TNF-α, MCP-1, MIP-2, and GRO-α, in a time-dependent manner (Fig. 1d), suggesting a preliminary inflammatory response at bacterial entry of the BBB.