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Comparative Analysis of Retro and Lentiviral Vector Integration into the Genome of Nonhuman Primates Long-Term Repopulating Cells

Peiman Hematti1,=A7, Bum-Kee Hong1,=A7, Cole Ferguson1,, Rima Adler1, Hideki Hanawa2, Stephanie Sellers1, Ingeborg E. Holt3, Craig E, Eckfeldt4, Manfred Schmidt5, Christof von Kalle6, Derek A. Persons2, Catherine M. Verfaillie4, Arthur W. Nienhuis2, Tyra G. Wolfsberg3, Cynthia E. Dunbar1,* and Boris Calmels1

1Hematology Branch, National Heart, Lung, and Blood Institute, Bethesda, MD, USA.
2Department of Hematology/Oncology, St. Jude Children's Research Hospital, Memphis, TN, USA.
3Genome Technology Branch, National Human Genome Research Institute, Bethesda, MD, USA.
4Stem Cell Institute, University of Minnesota, Minneapolis, MN, USA.
5Department of Internal Medicine, University of Freiburg, Freiburg, Germany.
6Division of Experimental Hematology, Children's Hospital Research Foundation, Cincinnati, OH, USA.

These authors contributed equally to this work.

*To whom correspondence and reprint requests should be addressed: Hematology Branch, Building 10, Room 7C103, NHBLI, NIH, 9000 Rockville Pike, Bethesda, MD 20892, USA. Fax: (301) 496-8396. E-mail: dunbarc@nhlbi.nih.gov


Abstract

Murine replication-defective oncoretroviruses are the most widely used vectors in hematopoietic stem cell gene transfer protocols. Occurrence of lymphoproliferative diseases in two children who received CD34+ cells transduced with murine leukemia virus (MLV) vector, and subsequent studies in cell lines, have confirmed the nonrandom integration pattern of oncoretroviral and lentiviral vectors into the genome of host cells. Therefore, insertion site analysis of retroviral vectors in an appropriate preclinical model (nonhuman primates) can provide valuable information for designing safer clinical trials. We studied the integration site pattern in peripheral blood cells of rhesus monkeys that had been previously transplanted with CD34+ cells transduced with either MLV or simian immunodeficiency virus (SIV) based lentiviral vector. Comparative analysis of the integration site locations revealed vector-specific integration biases: while MLV vectors integrate preferentially in the vicinity of transcription start sites, SIV insertions favored transcription units, with no obvious location preference within the coding regions themselves. These observations highlight distinct proviral integration patterns between oncoretroviruses and lentiviruses and may suggest different mechanisms for virus-specific integration site selection as well as different safety implications for gene therapy applications.


UCSC Tracks for MLV and SIV integration sites