Retroviral vector integration in post-transplant hematopoiesis in mice conditioned with either submyeloablative or ablative irradiation.
X-linked chronic granulomatous disease (X-CGD) is an inherited immunodeficiency with absent phagocyte NADPH-oxidase activity caused by defects in the gene-encoding gp91(phox). Here, we evaluated strategies for less intensive conditioning for gene therapy of genetic blood disorders without selective advantage for gene correction, such as might be used in a human X-CGD protocol. We compared submyeloablative with ablative irradiation as conditioning in murine X-CGD, examining engraftment, oxidase activity and vector integration in mice transplanted with marrow transduced with a gamma-retroviral vector for gp91(phox) expression. The frequency of oxidase-positive neutrophils in the donor population was unexpectedly higher in many 300 cGy-conditioned mice compared with lethally irradiated recipients, as was the fraction of vector-marked donor secondary CFU-S12. Vector integration sites in marrow, spleen and secondary CFU-S12 DNA from primary recipients were enriched for cancer-associated genes, including Evi1, and integrations in or near cancer-associated genes were more frequent in marrow and secondary CFU-S12 from 300 cGy-conditioned mice compared with fully ablated mice. These findings support the concept that vector integration can confer a selection bias, and suggest that the intensity of the conditioning regimen may further influence the effects of vector integration on clonal selection in post-transplant engraftment and hematopoiesis.
Sadat
M A
MA
Department of Pediatrics, Herman B Wells Center for Pediatric Research, Riley Hospital for Children, Indiana University School of Medicine, Indianapolis, IN 46202, USA.
Dirscherl
S
S
Sastry
L
L
Dantzer
J
J
Pech
N
N
Griffin
S
S
Hawkins
T
T
Zhao
Y
Y
Barese
C N
CN
Cross
S
S
Orazi
A
A
An
C
C
Goebel
W S
WS
Yoder
M C
MC
Li
X
X
Grez
M
M
Cornetta
K
K
Mooney
S D
SD
Dinauer
M C
MC
D000818:Animals; D001853:Bone Marrow / Q000528:radiation effects*; D005260:Female; D018014:Gene Transfer Techniques; D005822:Genetic Vectors; D006105:Granulomatous Disease, Chronic / Q000235:genetics / Q000628:therapy*; D006410:Hematopoiesis; D018380:Hematopoietic Stem Cell Transplantation; D008297:Male; D008562:Membrane Glycoproteins / Q000235:genetics; D051379:Mice; D008810:Mice, Inbred C57BL; D000074662:NADPH Oxidase 2; D019255:NADPH Oxidases / Q000235:genetics / Q000378:metabolism; D009369:Neoplasms / Q000235:genetics; D009504:Neutrophils / Q000378:metabolism; D012190:Retroviridae / Q000235:genetics*; D013234:Stem Cells; D014161:Transduction, Genetic; D019172:Transplantation Conditioning / Q000379:methods*; D016662:Virus Integration
D008562:Membrane Glycoproteins; C500593:Cybb protein, rat; D000074662:NADPH Oxidase 2; D019255:NADPH Oxidases