In Vivo Cellular MRI of Dendritic Cell Migration Using Micrometer-Sized Iron Oxide (MPIO) Particles

Purpose This study seeks to assess the use of labeling with micron-sized iron oxide (MPIO) particles for the detection and quantification of the migration of dendritic cells (DCs) using cellular magnetic resonance imaging (MRI). Procedures DCs were labeled with red fluorescent MPIO particles for detection by cellular MRI and a green fluorescent membrane dye (PKH67) for histological detection. MPIO-labeled DCs or unlabeled control DCs were injected into mice footpads at two doses (0.1 × 10 6 and 1 × 10 6 ). Images were acquired at 3 Tesla before DC injection and 2, 3, and 7 days post-DC injection. Results Labeling DCs with MPIO particles did not affect viability, but it did alter markers of DC activation and maturation. MRI and fluorescence microscopy allowed for the detection of MPIO-labeled DCs within the draining popliteal nodes after their injection into the footpad. Conclusions This paper presents the first report of the successful use of fluorescent MPIO particles to label and track DC migration.