European Journal of Nuclear Medicine and Molecular Imaging

, Volume 33, Issue 4, pp 474–482

Synthesis of 99mTc-HYNIC-interleukin-12, a new specific radiopharmaceutical for imaging T lymphocytes

  • Alessio Annovazzi
  • Calogero D’Alessandria
  • Elena Bonanno
  • Stephen J. Mather
  • Bart Cornelissen
  • Christophe van de Wiele
  • Rudi A. Dierckx
  • Maurizio Mattei
  • Graziana Palmieri
  • Francesco Scopinaro
  • Alberto Signore
Original article

DOI: 10.1007/s00259-005-0001-6

Cite this article as:
Annovazzi, A., D’Alessandria, C., Bonanno, E. et al. Eur J Nucl Med Mol Imaging (2006) 33: 474. doi:10.1007/s00259-005-0001-6

Abstract

Purpose

Few radiopharmaceuticals have been described for the study of lymphocyte trafficking despite its high clinical relevance. The main difficulty resides in the identification of a suitable highly specific probe to target these cells. Interleukin-12 (IL12) is a heterodimeric cytokine which plays a key role in the development of Th1 lymphocytes. The aims of the present study were to label IL12 with 99mTc, to evaluate its ability to bind to activated T lymphocytes in vitro and to study its biodistribution in normal mice and mice affected by autoimmune colitis.

Methods

IL12 was derivatised with HYNIC-NHS and labelled with 99mTc. An in vitro binding assay was performed on KIT225 cells, an IL12 receptor-positive cell line. 99mTc-IL12 biodistribution in normal mice was studied. Targeting experiments were performed in Balb/c mice injected with KIT225 cells and in mice with chemically induced chronic colitis.

Results

99mTc-IL12 labelling efficiency ranged between 75% and 85%. Saturation binding analysis revealed a Kd of 2.09 nM. Results of biodistribution studies showed a predominant hepatic route of excretion. A significant degree of uptake in the spleen and thymus was also observed. In mice injected with KIT225 cells, 99mTc-IL12-specific uptake in these cells increased over time. 99mTc-IL12 also accumulated significantly in bowel of mice affected by TNBS-induced colitis showing T lymphocyte infiltration at histology, while accumulation in colon from control animals was negligible.

Conclusion

We conclude that this radiolabelled cytokine is a suitable candidate for specific in vivo imaging of T lymphocytes: a step forward in molecular imaging of immune-mediated processes.

Keywords

Interleukin-12T lymphocytesHYNICMolecular imaging

Copyright information

© Springer-Verlag 2006

Authors and Affiliations

  • Alessio Annovazzi
    • 1
    • 5
  • Calogero D’Alessandria
    • 1
  • Elena Bonanno
    • 2
  • Stephen J. Mather
    • 3
  • Bart Cornelissen
    • 4
  • Christophe van de Wiele
    • 4
  • Rudi A. Dierckx
    • 5
  • Maurizio Mattei
    • 6
  • Graziana Palmieri
    • 6
  • Francesco Scopinaro
    • 1
  • Alberto Signore
    • 1
    • 5
  1. 1.Nuclear MedicineOspedale S. Andrea, 2nd Faculty of Medicine “La Sapienza”RomaItaly
  2. 2.Department of Biopathology and Diagnostic ImagingUniversity “Tor Vergata”RomeItaly
  3. 3.Cancer Research UKSt. Bartholomew’s HospitalLondonUK
  4. 4.Division of Nuclear MedicineUniversity of GentGentBelgium
  5. 5.Department of Nuclear MedicineUniversity of GroningenGroningenThe Netherlands
  6. 6.Department of BiologyNSTA, University “Tor Vergata”RomeItaly