title: Sensitivity of magnetic resonance imaging of dendritic cells for in vivo tracking of cellular cancer vaccines.
abstract: Success of immunotherapy with dendritic cells (DC) to treat cancer is highly dependent on their interaction with and activation of antigen specific T cells. To maximize DC-T cell contact accurate delivery of the therapeutic cells into the lymph node, or efficient trafficking of DC to the lymph nodes of the patient is essential. Since responses are seen in some patients but not in others, monitoring of the injected cells may be of major importance. Tracking of cells with magnetic resonance (MR) imaging is a non-invasive method that provides detailed anatomical information and is therefore more informative for the evaluation of the localization of therapeutic cells after injection than e.g. scintigraphic imaging. To challenge the sensitivity of this novel technique, we investigated the minimum amount of label and the number of cells required for MR imaging and the effect of labeling on DC function. DC were labeled with different concentrations of a clinically approved MR contrast agent consisting of superparamagnetic iron oxide particles and were imaged at both 3 and 7 T. Our results demonstrate the following: (i) When loaded with 30 (+/-4) pg Fe/cell, cell numbers as low as 1,000 cells/mm3 at 3 T and 500 cells/mm3 at 7 T could be readily imaged; (ii) Labeling does not affect cell viability and function; (iii) Because of its high spatial resolution and sensitivity, MRI is ideally suited to track therapeutic cells in vivo.
authors.affiliation: Department of Tumorimmunology, Nijmegen Centre for Molecular Life Science, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
authors.forename: Pauline
authors.initials: P
authors.lastname: Verdijk
authors.forename: Tom W J
authors.initials: TW
authors.lastname: Scheenen
authors.forename: W Joost
authors.initials: WJ
authors.lastname: Lesterhuis
authors.forename: Giulio
authors.initials: G
authors.lastname: Gambarota
authors.forename: Andor A
authors.initials: AA
authors.lastname: Veltien
authors.forename: Piotr
authors.initials: P
authors.lastname: Walczak
authors.forename: Nicole M
authors.initials: NM
authors.lastname: Scharenborg
authors.forename: Jeff W M
authors.initials: JW
authors.lastname: Bulte
authors.forename: Cornelis J A
authors.initials: CJ
authors.lastname: Punt
authors.forename: Arend
authors.initials: A
authors.lastname: Heerschap
authors.forename: Carl G
authors.initials: CG
authors.lastname: Figdor
authors.forename: I Jolanda M
authors.initials: IJ
authors.lastname: de Vries
mesh_terms: D019496:Cancer Vaccines / Q000276:immunology*; D002465:Cell Movement; D018920:Coculture Techniques; D003287:Contrast Media / Q000032:analysis; D003713:Dendritic Cells / Q000276:immunology*; D003911:Dextrans; D052203:Ferrosoferric Oxide; D006801:Humans; D007501:Iron / Q000032:analysis; D008213:Lymphocyte Activation; D008279:Magnetic Resonance Imaging / Q000379:methods*; D058185:Magnetite Nanoparticles; D009000:Monocytes / Q000276:immunology; D010087:Oxides / Q000032:analysis; D012680:Sensitivity and Specificity; D013601:T-Lymphocytes / Q000276:immunology
chemical_list: D019496:Cancer Vaccines; D003287:Contrast Media; D003911:Dextrans; D058185:Magnetite Nanoparticles; D010087:Oxides; D007501:Iron; C065507:ferumoxides; D052203:Ferrosoferric Oxide