Kinetic analysis of the accumulation of mononuclear and granulocytic innate immune cells in the lungs following sub-lethal infection of mice with the mouse-adapted IAV strain, A/Puerto Rico/8/34 (PR8) revealed that inflammatory mononuclear cells of the dendritic cell (DC)/macrophage lineage (so called exudate macrophages, TNF iNOS-producing DCs [15], [16]; CD45+, Ly6Chi, Ly6G−, CD11bhi, CD11chi) were the most prominent innate immune cell type identified with maximum accumulation occurring approximately 10–12 days post infection (dpi) (Figure 1A and see Figure S1 for gating strategy). This evidence concerns the gene PTPRC and infection.