title: Feasibility and limits of magnetically labeling primary cultured rat T cells with ferumoxides coupled with commonly used transfection agents.
abstract: Visualization and quantification of inflammatory processes is of high importance for early diagnosis of a multitude of diseases. Magnetic resonance imaging (MRI) using iron oxide (FeO) nanoparticles as contrast agents allows the study of macrophage infiltration during inflammation in a variety of tissues. Macrophages are effectors of the immune response, their appearance being orchestrated by activated T lymphocytes. Therefore, tracking of labeled T lymphocytes, which initiate the immune process, should enable earlier detection of tissue inflammation. In this study, we investigate the feasibility of specifically labeling harvested T cells by using dextran-coated FeO nanoparticles and commonly available transfection agents (TAs). Physicochemical properties of the newly formed FeO/TA vesicles were determined as well as their cell toxicity and their T cell activation potential. The labeling efficiency of each FeO/TA combination was evaluated by measuring the transverse MRI relaxation rate R(2) by X-ray spectroscopy and magnetic selection. Toxicity and labeling efficacy differed significantly among TAs. The best results were achieved by using polyamine TAs and in particular by using poly-l-lysine at a concentration of 1.5 microg/mL administered in combination with 22.5 microg iron/mL. By using this protocol, up to 60% of harvested T cells could be labeled. Microscopic investigation revealed FeO/TA nanoparticles not only localized within the cytoplasma of the cells but also sticking to the outer membrane surface.
authors.affiliation: Novartis Institutes for Biomedical Research, Switzerland.
authors.forename: Cedric
authors.initials: C
authors.lastname: Berger
authors.forename: Martin
authors.initials: M
authors.lastname: Rausch
authors.forename: Philipp
authors.initials: P
authors.lastname: Schmidt
authors.forename: Markus
authors.initials: M
authors.lastname: Rudin
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D003287:Contrast Media; D003911:Dextrans; D005240:Feasibility Studies; D052203:Ferrosoferric Oxide; D007501:Iron; D008055:Lipids; D008279:Magnetic Resonance Imaging; D058185:Magnetite Nanoparticles; D010087:Oxides; D011094:Polyethyleneimine; D011107:Polylysine; D051381:Rats; D011917:Rats, Inbred Lew; D013194:Staining and Labeling; D013601:T-Lymphocytes / Q000378:metabolism*; D014162:Transfection / Q000379:methods*
chemical_list: D003287:Contrast Media; D003911:Dextrans; D008055:Lipids; C086724:Lipofectamine; D058185:Magnetite Nanoparticles; D010087:Oxides; D011107:Polylysine; D011094:Polyethyleneimine; D007501:Iron; C065507:ferumoxides; D052203:Ferrosoferric Oxide