Polyclonal human immunoglobulin G labeled with polymeric iron oxide: antibody MR imaging

Radiology. 1991 Oct;181(1):245-9. doi: 10.1148/radiology.181.1.1887040.


Human polyclonal immunoglobulin (Ig) G was attached to a monocrystalline iron oxide nanocompound (MION), a small superparamagnetic probe developed for receptor and antibody magnetic resonance (MR) imaging. The resulting complex, MION-IgG, had a slightly negative surface charge, a molecular weight of 150-180 kDa, and 0.36 microgram of IgG attached per milligram of iron. After intravenous administration of MION-IgG to normal rats, most of the compound localized in liver, spleen, and bone marrow. In an animal model of myositis, MION-IgG caused reduced signal intensity (most apparent on T2-weighted spin-echo and gradient-echo images) at the site of inflammation. No change in signal intensity existed after an injection of unlabeled MION. Site-specific localization of MION-IgG was corroborated with scintigraphic imaging with indium-111 IgG and MION-In-111-IgG and was confirmed histologically with iron staining. These results indicate that antibody MR imaging is feasible in vivo. Target-specific and antibody MR imaging could be easily extended to other applications, including detection of cancer, infarction, and degenerative diseases.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Contrast Media*
  • Dextrans
  • Ferrosoferric Oxide
  • Humans
  • Immunoglobulin G*
  • Indium Radioisotopes
  • Iron*
  • Magnetic Resonance Imaging / methods*
  • Magnetite Nanoparticles
  • Myositis / diagnosis
  • Oxides*
  • Polymers
  • Rats


  • Contrast Media
  • Dextrans
  • Immunoglobulin G
  • Indium Radioisotopes
  • Magnetite Nanoparticles
  • Oxides
  • Polymers
  • polymeric IgG
  • Iron
  • ferumoxides
  • Ferrosoferric Oxide