S. Barrette et al., Lentivirus-based vectors transduce mouse hematopoietic stem cells with similar efficiency to Moloney murine leukemia virus-based vectors, BLOOD, 96(10), 2000, pp. 3385-3391
The low levels of transduction of human hematopoietic stem cells (HSCs) wit
h Moloney murine leukemia virus (MLV) vectors have been an obstacle to gene
therapy for hematopoietic diseases. It has been demonstrated that lentivir
us vectors are more efficient than MLV vectors at transducing nondividing c
ell lines as well as human CD34(+) cells and severe combined immunodeficien
cy disease repopulating cells. We compared transduction of cell lines and L
in(-) bone marrow cells, using a vesicular stomatitis virus G (VSV-G)-pseud
otyped lentivirus or MLV vectors carrying a green fluorescent protein marke
r gene. As predicted, the lentivirus vector was more efficient at transduci
ng mouse and human growth-inhibited cell lines. The transduction of mouse H
SC by lentivirus vectors was compared directly to MLV vectors in a co-trans
duction assay. In this assay, transduction by ecotropic MLV is a positive i
nternal control for downstream steps in retrovirus transduction, including
cell division. Both the VSV-G lentivirus and MLV vectors transduced mouse H
SCs maintained in cytokine-free medium at very low frequency, as did the ec
otropic control. The lentivirus vector and the MLV vector were equally effi
cient at transducing bone marrow HSCs cultured in interleukin 3 (IL-3), IL-
6, and stem cell factor for 96 hours. In conclusion, although lentivirus ve
ctors are able to transduce growth-inhibited cell lines, the cell cycle sta
tus of HSCs render them resistant to lentivirus-mediated transduction, and
it is hypothesized that entry into cycle, not necessarily division, may be
a requirement for efficient lentivirus-mediated transduction. (C) 2000 by T
he American Society of Hematology.