ERVW-1 and cystic fibrosis: Our ongoing efforts to improve pulmonary gene transfer for the treatment of lung diseases such as cystic fibrosis (CF), have led to the development of a novel lentiviral vector (simian immunodeficiency virus [SIV]) pseudotyped with the Sendai virus (SeV) envelope proteins F and HN (recombinant (r)SIV.F/HN).