Once M1-phenotype macrophages have activated themselves through cytokines such as interferon (IFN)-γ, tumor necrosis factor (TNF)-α, or lipopolysaccharide (LPS) [29, 30], they further produce pro-inflammatory and immune-stimulating cytokines and participate in the anti-infection response together with helper T cells 1 (Th1). Here, TNF is linked to infection.