title: The migration of synthetic magnetic nanoparticle labeled dendritic cells into lymph nodes with optical imaging.
abstract: BACKGROUND
  The successful biotherapy of carcinoma with dendritic cell (DC) vaccines pivotally relies on DCs' migratory capability into lymph tissues and activation of T cells. Accurate imaging and evaluation of DC migration in vivo have great significance during antitumor treatment with DC vaccine. We herein examined the behavior of DCs influenced by synthetic superparamagnetic iron oxide (SPIO) nanoparticle labeling.
  
  
  METHODS
  γ-Fe2O3 nanoparticles were prepared and DCs, which were induced from bone marrow monocytes of enhanced green fluorescent protein (EGFP) transgenic mice, were labeled. The endocytosis of the SPIO, surface molecules, cell apoptosis and fluorescence intensity of EGFP-DCs were displayed by Prussian blue staining and flow cytometry (FCM), respectively. After EGFP-DCs, labeled with SPIO, were injected into footpads (n = 5) for 24 hours, the mice were examined in vivo by optical imaging (OPI). Meanwhile, confocal imaging and FCM were applied, respectively, to detect the migration of labeled DCs into draining lymph nodes.
  
  
  RESULTS
  Nearly 100% of cells were labeled by the SPIO, in which the intracellular blue color gradually deepened and the iron contents rose with the increase of labeling iron concentrations. In addition, cell apoptosis and the surface molecules on DCs were at similar levels after SPIO labeling. After confirming that the fluorescence intensity of EGFP on DCs was not influenced by SPIO, the homing ability of EGFP-DCs labeled with SPIO displayed that the fluorescence intensity and the ratios of EGFP-DCs in draining lymph nodes were gradually decreased with the increase of labeling iron concentrations.
  
  
  CONCLUSIONS
  The synthetic SPIO nanoparticles possess perfect labeling ability and biocompatibility. Moreover, DCs labeled with a low dose of SPIO showed stronger migratory capability in vivo.
authors.affiliation: Center Laboratory of Stomatology, Stomatological Hospital Affiliated Medical School, Nanjing University, Nanjing, People's Republic of China.
authors.forename: Hang
authors.initials: H
authors.lastname: Su
authors.forename: Yongbin
authors.initials: Y
authors.lastname: Mou
authors.forename: Yanli
authors.initials: Y
authors.lastname: An
authors.forename: Wei
authors.initials: W
authors.lastname: Han
authors.forename: Xiaofeng
authors.initials: X
authors.lastname: Huang
authors.forename: Guohua
authors.initials: G
authors.lastname: Xia
authors.forename: Yanhong
authors.initials: Y
authors.lastname: Ni
authors.forename: Yu
authors.initials: Y
authors.lastname: Zhang
authors.forename: Jianmin
authors.initials: J
authors.lastname: Ma
authors.forename: Qingang
authors.initials: Q
authors.lastname: Hu
mesh_terms: D000818:Animals; D002465:Cell Movement / Q000502:physiology; D058948:Cell Tracking / Q000379:methods*; D003713:Dendritic Cells / Q000166:cytology* / Q000502:physiology*; D003911:Dextrans; D005260:Female; D008198:Lymph Nodes / Q000166:cytology* / Q000502:physiology*; D058185:Magnetite Nanoparticles / Q000737:chemistry / Q000648:ultrastructure; D051379:Mice; D008810:Mice, Inbred C57BL; D008856:Microscopy, Fluorescence / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D003911:Dextrans; D058185:Magnetite Nanoparticles; C097921:ferumoxtran-10
keywords: cell tracking; dendritic cell; optical imaging; superparamagnetic iron oxide