Pulmonary pathological injury was also alleviated in PNP-CKO mice at 6 days post-infection (dpi), evidenced by reduced hemorrhage, necrocytosis of epithelial cells, infiltration of inflammatory cells within the lung tissues, and suppressed proinflammatory cytokines production (IL-6, TNF-ɑ) in the peripheral blood (Fig. 2i, j). This evidence concerns the gene TNF and infection.