Long-term in vivo expression of the MFG-ADA retroviral vector in rhesus monkeys transplanted with transduced bone marrow cells.
We have tested the recombinant human adenosine deaminase (hADA) retroviral vector MFG-ADA for its efficacy in transducing hemopoietic stem cells of nonhuman primates and its expression level in the hematopoietic system. The percentage of provirus-positive granulocytes 1 year after transplantation of bone marrow transduced with MFG-ADA was 0.1%, which was equivalent to previously obtained results with the hADA virus-producing cell line POC-1. However, in MFG-ADA monkeys, significantly more peripheral blood mononuclear cells carried the hADA gene (1% versus 0.1%). Human ADA expression levels in peripheral blood mononuclear cells were different between POC-1 and MFG-ADA monkeys using samples with equal numbers of provirus copies per cell. In contrast, in total red blood cell lysates of MFG-ADA monkeys, the hADA expression was higher (approximately 10-fold) and could be detected longer (20 weeks and up to more than 1 year after bone marrow transplantation in 2 monkeys) than in POC-1 monkeys that were only positive for up to 12 weeks at the most. At 3 years after bone marrow transplantation, the MFG-ADA provirus could still be detected in 0.1% of bone marrow cells and peripheral blood cells and in 1% of cultured T cells. These results show that MFG-ADA virus can give rise to long-term in vivo expression of hADA in the primate hematopoietic system. However, transduction efficiencies remain low.
Kaptein
L C
LC
Department of Molecular Cell Biology, University of Leiden, The Netherlands.
Van Beusechem
V W
VW
Rivière
I
I
Mulligan
R C
RC
Valerio
D
D
D016475:3T3 Cells; D000243:Adenosine Deaminase / Q000235:genetics*; D000818:Animals; D016026:Bone Marrow Transplantation; D018920:Coculture Techniques; D005822:Genetic Vectors; D006412:Hematopoietic Stem Cells / Q000201:enzymology; D006801:Humans; D008212:Lymphocyte Depletion; D008253:Macaca mulatta; D051379:Mice; D014161:Transduction, Genetic
D000243:Adenosine Deaminase