To characterize the effects of epitope-tagged FL IFITM3 and Δ21 IFITM3 on viral entry, A549 cells, a human lung adenocarcinoma epithelial cell line, were transduced with tet-inducible plasmids encoding FL IFITM3 or Δ21 IFITM3, respectively. The gene discussed is IFITM3; the disease is lung adenocarcinoma.