CCL2 and infection: Upon stimulation, PRRs transduce signals that activate macrophages to secrete inflammatory mediators, including proinflammatory cytokines, such as TNF-α, IL-1β, and IL-6; chemokines, such as CXCL8 (also called IL-8) and CCL2 (also called MCP-1); and lipid mediators, which in turn mediate leukocyte recruitment to the site of infection or tissue injury.