Repetitive Noninvasive Monitoring of HSV1-tk-Expressing T Cells Intravenously Infused into Nonhuman Primates Using Positron Emission Tomography and Computed Tomography with 18F-FEAU.

Adoptive transfer of antigen-specific cytotoxic T lymphocytes (CTLs) has been successfully used to treat patients with different types of cancer, However, the long-term spatial-temporal dynamics of the distribution of systemically infused CTLs remains largely unknown, Noninvasive imaging of adoptively transferred CTLs using molecular-genetic reporter imaging with positron emission tomography and computed tomography (PET-CT) represents an innovative approach to understanding the long-term migratory patterns and therapeutic potential of adoptively transferred T cells, Here we report the application of repetitive PET-CT imaging with [¹⁸F]fluoro-5-ethyl-1-beta-D-arabinofuranosyluracil (¹⁸F-FEAU) in two nonhuman primates demonstrating that autologous polyclonal macaque T lymphocytes activated and transduced with a retroviral vector encoding for the sr39 mutant herpes simplex virus 1 thymidine kinase (sr39HSV1-tk) reporter gene can be detected after intravenous infusion in discrete lymphoid organs and in sites of inflammation, This study represents a proof of principle and supports the application of ¹⁸F-FEAU PET-CT imaging for monitoring the distribution of intravenously administered sr39HSV1-tk gene-transduced CTLs in humans. [ABSTRACT FROM AUTHOR]