title: Monoclonal antibodies conjugated with superparamagnetic iron oxide particles allow magnetic resonance imaging detection of lymphocytes in the mouse brain.
abstract: We investigated the potential of antibody-vectorialized superparamagnetic iron oxide (SPIO) particles as cellular specific magnetic resonance contrast agents to image lymphocyte populations within the central nervous system (CNS), with the final goal of obtaining a reliable tool for noninvasively detecting and tracking specific cellular populations in vivo. We used superparamagnetic particles bound to a monoclonal antibody. The particle is the contrast agent, by means of its T₂* relaxation properties; the antibody is the targeting vector, responsible for homing the particle to target a surface antigen. To investigate the efficiency of particle vectorialization by these antibodies, we compared two types of antibody-vectorialized CD3-specific particles in vivo. We successfully employed vectorialized SPIO particles to image B220⁺ cells in a murine model of B-cell lymphoma. Likewise, we were able to identify CD3⁺ infiltrates in a murine model of multiple sclerosis. The specificity of the technique was confirmed by immunohistochemistry and electron microscopy of corresponding sections. Our findings suggest that indirect binding of the antibody to a streptavidinated particle allows for enhanced particle vectorialization compared to covalent binding of the antibody to the particle.
authors.affiliation: Department of Clinical Neuroimmunology, San Raffaele Scientific Institute, Milan, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Luchetti
authors.forename: Davide
authors.initials: D
authors.lastname: Milani
authors.forename: Francesca
authors.initials: F
authors.lastname: Ruffini
authors.forename: Rossella
authors.initials: R
authors.lastname: Galli
authors.forename: Andrea
authors.initials: A
authors.lastname: Falini
authors.forename: Angelo
authors.initials: A
authors.lastname: Quattrini
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Scotti
authors.forename: Giancarlo
authors.initials: G
authors.lastname: Comi
authors.forename: Gianvito
authors.initials: G
authors.lastname: Martino
authors.forename: Roberto
authors.initials: R
authors.lastname: Furlan
authors.forename: Letterio S
authors.initials: LS
authors.lastname: Politi
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D001921:Brain / Q000166:cytology*; D003911:Dextrans / Q000008:administration & dosage; D004681:Encephalomyelitis, Autoimmune, Experimental / Q000175:diagnosis; D005260:Female; D006801:Humans; D007267:Injections; D016393:Lymphoma, B-Cell / Q000175:diagnosis; D008279:Magnetic Resonance Imaging / Q000379:methods*; D058185:Magnetite Nanoparticles / Q000008:administration & dosage; D051379:Mice; D012680:Sensitivity and Specificity; D013601:T-Lymphocytes / Q000166:cytology*
chemical_list: D000911:Antibodies, Monoclonal; D003911:Dextrans; D058185:Magnetite Nanoparticles; C065507:ferumoxides