CX3CL1 and viral infectious disease: A study has reported that microglia are powerful producers of type I interferons, proinflammatory cytokines (such as interleukin [16]-1β, IL-6, and tumor necrosis factor [TNF]-α), and chemokines (such as chemokine ligand 2 [CCL2], monocyte chemoattractant protein-1 [MCP-1], chemokine (C-X3-C motif) ligand 1 [CX3CL1]) in response to viral infection [17].