High-level transgene expression in human hematopoietic progenitors and differentiated blood lineages after transduction with improved lentiviral vectors

Recent experiments point to the great value of lentiviral vectors for the t ransduction of human hematopoietic stem cells (hHSCs). Vectors used so far, however, have been poorly satisfying in terms of either biosafety or effic iency of transgene expression. Herein is described the results obtained wit h human immunodeficiency virus-based vectors optimized in both of these asp ects. It is thus shown that vectors containing the EF1 alpha and, to a less er extent, the phosphoglycerate kinase (PGK) promoter, govern high-level ge ne expression in human hematopoietic progenitors as well as derived hematop oietic lineages of therapeutic relevance, such as erythrocytes, granulocyte s, monocytes, dendritic cells, and megakaryocytes. EF1 alpha promoter-conta ining lentiviral vectors can also induce strong transgene expression in pri mary T lymphocytes isolated from peripheral blood. A self-inactivating desi gn: did net affect the performance of EF1 alpha promoter-based vectors but significantly reduced expression from the PGK promoter. This negative effec t could nevertheless be largely rescued by inserting the post-transcription al regulatory element of woodchuck hepatitis virus upstream of the vector 3 ' long terminal repeat. These results have important practical implications for the genetic treatment of lymphohematologic disorders as well as for th e study of hematopoiesis via the lentivector-mediated modification of hHSCs . (C) 2000 by The American Society of Hematology.