Although a relatively lower CD45+ cell infiltration in the SARS-CoV-2 single-infection group than that in the IAV single-infection group was observed at 2 dpi, the SARS-CoV-2 single-infection group showed a rapid increase in the CD45+ cell numbers in the BALF from 5 dpi (Fig. 3A, right). This evidence concerns the gene PTPRC and infection.