TNF and infectious disease: Microglia are essential for tissue repair processes and the maintenance of homeostasis during infectious diseases, ischemic lesions, and tumor growth, which can activate the over-expression of proinflammatory cytokines, e.g., TNF-α, IL-1β as well as neurotoxic radicals, e.g., ROS, nitric oxide (Singhal and Baune, 2017).