CX3CL1 and brain ischemia: Identical to cytokines, chemokines and their receptors are usually expressed in low concentrations [163, 164], but after cerebral ischemia, TNF-α and IL-1β enhance the production and release of specific chemokines such as cytokine-induced neutrophil chemoattractant (CINC), monocyte chemoattractant 1 (MCP-1), microglial response factor-1 (MRF-1), and fractalkine and macrophage inflammatory protein 1 (MIP-1) which are upregulated in the first 3 h and remain elevated for at least 6 h [163].