Using expression of the c-kit antigen as an identifier, Brigham researchers Kajstura et al identified stem cells in adult human lungs (from unused donor lungs and a Brigham tissue bank), established a clonal cell line from the isolated stem cells, and infected those cells with a fluorescing lentivirus. With a cryoprobe, they destroyed some mice's lung tissue, and injected the cultured stem cells into the cyclosporine-treated mice. Two weeks later,