The interferon-stimulated genes (ISGs), ISG15 and MX Dynamin-Like GTPase 1 (MX1), were also elevated at 3 dpi, indicating that airway tissue explants are not only infectable but can also respond to viral infection by activating interferon-mediated host innate defense pathways (Fig. 8, H and I). This evidence concerns the gene STING1 and viral infectious disease.