Both cell populations upregulated ISGs in response to viral infection, including factors that inhibit viral entry into the host cell (IFN-induced transmembrane protein 1 (IFITM1)), intracellular replication of virus (eukaryotic translation initiation factor 2-alpha kinase 2 (EIF2AK2) and radical SAM domain-containing 2 (RSAD2), also known as viperin), and viral egress from the cell (IFN-stimulated gene 15 (ISG15)) (Figures 4(c) and 4(d), resp). The gene discussed is ISG15; the disease is viral infectious disease.