IFNG and pneumococcal infection: DEPs were inflammatory in the absence of pneumococcal infection, leading to significantly increased levels of TNF-α, IFN-γ, keratinocyte chemoattractant/human growth-regulated oncogene (KC/GRO), macrophage inflammatory protein 2, and IL-1β compared with the levels in pneumococcus-infected control mice at day 1 postinfection (Fig 2, A-E).