Addition of the human interferon beta scaffold attachment region to retroviral vector backbones increases the level of in vivo transgene expression among progeny of engrafted human hematopoietic stem cells
L. Murray et al., Addition of the human interferon beta scaffold attachment region to retroviral vector backbones increases the level of in vivo transgene expression among progeny of engrafted human hematopoietic stem cells, HUM GENE TH, 11(14), 2000, pp. 2039-2050
Absence of durable high-level expression of transgenes from Moloney murine
leukemia (Mo-MuLV) retroviral vectors has been a hurdle in bringing effecti
ve gene therapy to the clinic. In this study we have analyzed transgene exp
ression among the progeny of mobilized hematopoietic stem cells (HSCs), com
paring Mo-MuLV and mouse stem cell virus (MSCV) vectors, with or without ad
dition of a scaffold attachment region (SAR) from the human interferon beta
gene. Retroviral (RV) vector supernatant quality was assessed by comparing
NGFR transgene expression by HEL cells, and transgene delivery and express
ion by CD34(+) cells 72 hr after transduction, using real-time PCR and FAGS
analysis. This is the first description of the effect of SAR within both M
o-MuLV and MSCV vector backbones on long-term RV transgene expression among
in vivo HSC progeny in HSC repopulation assays (SCID-hu bone and NOD/SCID)
, After transduction of mobilized CD34(+) cells with MSCV-SAR vector, trans
gene expression was observed among a mean of 10% of donor HSC progeny in th
e SCID-hu bone (range, 0.6-43%). The predominant effect of SAR was to incre
ase the mean fluorescence intensity (MFI) of transgene expression among HSC
progeny in both in vivo bone repopulation models (three- to fourfold), and
after long-term stromal cultures (twofold),.