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Updated: Mar 17, 2026
In vivo 19F MRI for Cell Tracking
Published on: November 25, 2013
(19)F-MRI for monitoring human NK cells in vivo
Myriam N Bouchlaka1, Kai D Ludwig2, Jeremy W Gordon2
1Department of Pediatrics, Carbone Cancer Center, University of Wisconsin School of Medicine and Public Health , Madison, WI, USA.
Abstract:
The availability of clinical-grade cytokines and artificial antigen-presenting cells has accelerated interest in using natural killer (NK) cells as adoptive cellular therapy (ACT) for cancer. One of the technological shortcomings of translating therapies from animal models to clinical application is the inability to effectively and non-invasively track these cells after infusion in patients. We have optimized the nonradioactive isotope fluorine-19 ((19)F) as a means to label and track NK cells in preclinical models using magnetic resonance imaging (MRI). Human NK cells were expanded with interleukin (IL)-2 and labeled in vitro with increasing concentrations of (19)F. Doses as low as 2 mg/mL (19)F were detected by MRI. NK cell viability was only decreased at 8 mg/mL (19)F. No effects on NK cell cytotoxicity against K562 leukemia cells were observed with 2, 4 or 8 mg/mL (19)F. Higher doses of (19)F, 4 mg/mL and 8 mg/mL, led to an improved (19)F signal by MRI with 3 × 10(11) (19)F atoms per NK cell. The 4 mg/mL (19)F labeling had no effect on NK cell function via secretion of granzyme B or interferon gamma (IFNγ), compared to NK cells exposed to vehicle alone. (19)F-labeled NK cells were detectable immediately by MRI after intratumoral injection in NSG mice and up to day 8. When (19)F-labeled NK cells were injected subcutaneously, we observed a loss of signal through time at the site of injection suggesting NK cell migration to distant organs. The (19)F perfluorocarbon is a safe and effective reagent for monitoring the persistence and trafficking of NK cell infusions in vivo, and may have potential for developing novel imaging techniques to monitor ACT for cancer.
Insights
Fluorine-19 ((19)F) labeling allows non-invasive tracking of natural killer (NK) cells for cancer adoptive cellular therapy (ACT). This method safely monitors NK cell persistence and migration in preclinical models using magnetic resonance imaging (MRI).
Area of Science:
- Biomedical Imaging
- Cellular Therapy
- Immunology
Background:
- Natural killer (NK) cells are a promising avenue for adoptive cellular therapy (ACT) in cancer treatment.
- A key challenge in translating NK cell therapies is the inability to track infused cells non-invasively in patients.
- Current tracking methods often lack sensitivity or require invasive procedures, limiting clinical application.
Purpose of the Study:
- To optimize fluorine-19 ((19)F) labeling for tracking NK cells using magnetic resonance imaging (MRI).
- To assess the safety and efficacy of (19)F labeling on NK cell function and viability.
- To evaluate the in vivo detectability and migration patterns of (19)F-labeled NK cells in preclinical models.
Main Methods:
- Human NK cells were expanded and labeled in vitro with varying concentrations of (19)F perfluorocarbon.
- NK cell viability, cytotoxicity, and cytokine secretion (granzyme B, IFNγ) were assessed post-labeling.
- MRI was used to detect (19)F-labeled NK cells following intratumoral and subcutaneous injection in NSG mice.
Main Results:
- (19)F labeling was detectable by MRI at doses as low as 2 mg/mL, with optimal signal at 4-8 mg/mL.
- NK cell viability and cytotoxic function against K562 leukemia cells remained unaffected at effective labeling concentrations (2-8 mg/mL).
- (19)F-labeled NK cells were visualized immediately post-injection and up to 8 days, with evidence of migration from injection sites.
Conclusions:
- Fluorine-19 ((19)F) perfluorocarbon is a safe and effective reagent for labeling NK cells for MRI tracking.
- This technique enables non-invasive monitoring of NK cell persistence and trafficking in vivo.
- The (19)F labeling method holds potential for advancing imaging techniques to monitor NK cell-based cancer therapies.
