Molecular Imaging (Mar 2012)

Monoclonal Antibodies Conjugated with Superparamagnetic Iron Oxide Particles Allow Magnetic Resonance Imaging Detection of Lymphocytes in the Mouse Brain

  • Alessandro Luchetti,
  • Davide Milani,
  • Francesca Ruffini,
  • Rossella Galli,
  • Andrea Falini,
  • Angelo Quattrini,
  • Giuseppe Scotti,
  • Giancarlo Comi,
  • Gianvito Martino,
  • Roberto Furlan,
  • Letterio S. Politi

DOI
https://doi.org/10.2310/7290.2011.00032
Journal volume & issue
Vol. 11

Abstract

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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 T 2 * 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.