1. Evaluation of Two Internalizing Carcinoembryonic Antigen Reporter Genes for Molecular Imaging
- Author
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Barat, Bhaswati, Kenanova, Vania E, Olafsen, Tove, and Wu, Anna M
- Subjects
Biomedical and Clinical Sciences ,Oncology and Carcinogenesis ,Biotechnology ,Cancer ,Genetics ,Biomedical Imaging ,Animals ,Carcinoembryonic Antigen ,Endocytosis ,Female ,Flow Cytometry ,Genes ,Reporter ,Humans ,Immunoglobulin Fragments ,Immunohistochemistry ,Jurkat Cells ,Mice ,Mice ,Nude ,Molecular Imaging ,Positron-Emission Tomography ,Recombinant Proteins ,Transfection ,Xenograft Model Antitumor Assays ,Antibody fragment ,CEA reporter gene ,Internalization ,Jurkat ,PET ,Physiology ,Clinical Sciences ,Nuclear Medicine & Medical Imaging ,Clinical sciences - Abstract
PurposeThe objective of this article is to develop internalizing positron emission tomography (PET) reporter genes for tracking genetically modified T cells in vivo.ProceduresThe transmembrane and cytoplasmic domains of the human transferrin receptor (TfR) and CD5 were each fused to the carcinoembryonic (CEA) minigene N-A3 and expressed in Jurkat T cells. Internalization was evaluated by confocal microscopy or by intracellular uptake of ¹²⁵I-labeled anti-CEA scFv-Fc. Reporter gene-transfected Jurkat xenografts in mice were analyzed by immunohistochemistry (IHC) and imaged by PET using ¹²⁴I- or ⁶⁴Cu-scFv-Fc as tracers.ResultsSurface expression of TR(1-99)-NA3 was lower than that of NA3-CD5. Both reporter genes were internalized following binding of the anti-CEA antibody fragment. IHC of tumors showed strong staining of NA3-CD5, whereas TR(1-99)-NA3 stained weakly. Specific targeting of TR(1-99)-NA3 or NA3-CD5 was shown by PET in xenografted mice.ConclusionsThe in vivo imaging studies suggest a potential application of the internalizing form of CEA (N-A3) as a PET reporter gene.
- Published
- 2011