Noninvasive molecular imaging to detect transgene expression of lentiviral vector in nonhuman primates.
Noninvasive imaging of a reporter gene is a new and promising technique to quantify transgene expression after gene therapy. This study was performed to demonstrate visualization of lentiviral-marked cells by PET.


METHODS
We transduced nonhuman primate CD34+ hematopoietic cells with a lentiviral vector expressing a PET reporter gene, the mutant viral herpes simplex virus type 1-thymidine kinase (HSV1-sr39tk) gene. 1-(2-Fluoro-2-deoxy-beta-D-arabinofuranosyl)-76Br-5-bromouracil (76Br-FBAU) was used as the substrate for the viral tk enzyme. Upon phosphorylation, 76Br-FBAU was retained by cells and imaged by PET. The long half-life of 76Br, 16.2 h, permitted us to perform extended pharmacokinetic and imaging studies.


RESULTS
76Br-FBAU was retained in vascular tissues of the animals with transplanted tk lentiviral vector-transduced CD34+ cells. Elimination of 76Br-FBAU was through renal and hepatic excretion.


CONCLUSIONS
Noninvasive molecular imaging using PET will help us, in the future, to define the contribution and distribution of cells and their progeny to tissue repair and development.
Sander
William E
WE
Hematology Branch, National Heart, Lung, and Blood Institute, Rockville, Maryland 20850, USA.
Metzger
Mark E
ME
Morizono
Kouki
K
Bonifacino
Aylin
A
Penzak
Scott R
SR
Xie
Yi-Ming
YM
Chen
Irvin S Y
IS
Bacon
Jeffrey
J
Sestrich
Stephen G
SG
Szajek
Lawrence P
LP
Donahue
Robert E
RE
D000818:Animals; D018952:Antigens, CD34 / Q000096:biosynthesis*; D001967:Bromine Radioisotopes / Q000494:pharmacology; D017690:Cell Transplantation; D017357:Cyclotrons; D003952:Diagnostic Imaging / Q000379:methods*; D018014:Gene Transfer Techniques; D017930:Genes, Reporter; D015316:Genetic Therapy / Q000379:methods; D005822:Genetic Vectors; D016086:Lentivirus / Q000235:genetics*; D008251:Macaca; D009154:Mutation; D049268:Positron-Emission Tomography / Q000379:methods
D018952:Antigens, CD34; D001967:Bromine Radioisotopes