TNF and infection: As described in the previous section, infection of the epithelial-endothelial barrier and of alveolar macrophages releases a flood of chemoattractant molecules as well as a variety of activating and signaling cytokines, including type I IFNs, TNF-α, IL-1α, IL-1β, and IL-33 (Sanders et al., 2011; Teijaro et al., 2011).