The present invention provides a retroviral vector containinga membrane protein having a hemagglutinin activity. The presentinventors constructed a retroviral vector pseudotyped by the membraneprotein having a hemagglutinin activity. This viral vector showedgene transfer at a high efficiency into host cells. In particular,it was established that genes can be transferred thereby at a highefficiency into cells into which genes can hardly be transferred bythe conventional techniques, for example, blood cells andhematopoietic cells including hematopoietic stem cells, and mucouscells including mucosa epithelial cells. The viral vector of thepresent invention is highly useful as a vector for gene therapy.
