Omer Aras MD, Presenter: Nothing to Disclose

Maria Berg PhD, Abstract Co-Author: Nothing to Disclose

Jeremy Pantin MD, Abstract Co-Author: Nothing to Disclose

Lawrence Szajek PhD, Abstract Co-Author: Nothing to Disclose

Chang H. Paik, Abstract Co-Author: Nothing to Disclose

Joseph Alan Frank MD, Abstract Co-Author: Nothing to Disclose

Noriko Sato MD, Abstract Co-Author: Nothing to Disclose

Richard W. Childs MD, Abstract Co-Author: Nothing to Disclose

Peter L. Choyke MD, Abstract Co-Author: Researcher, Koninklijke Philips Electronics NV Researcher, General Electric Company Researcher, Siemens AG Researcher, F. Hoffmann-La Roche Ltd Researcher, iCAD, Inc

The aim of this study is to explore the feasibility of using 89Zr for labeling and PET imaging of human Natural Killer (NK) cells.

Human NK cells were labeled with 89Zr alone, 89Zr with protamine sulfate (PS) or 89Zr with PS and heparin (H) mixture. The effects of the labeling on cell viability were examined by Trypan blue staining as well as an Annexin-V based flow cytometric assay for apoptosis. Expanded NK cells were evaluated for phenotypic changes after immediate labeling and at 24hr. MicroPET imaging of the labeled cells was performed.

A high level of cell labeling was achieved after incubating NK cells with 89Zr for 30 min in the presence of the PS-H serum-free mixture. The 89Zr-PS-H labeled NK cells had comparable TRAIL and NKG2D expression compared to cells exposed to PS-H alone for up to 24 hr. A less than 5% difference in cell viability was observed between 89Zr-PS-H and non-radiolabeled PS-H only conditions. Both in vitro microPET imaging and gamma counting of labeled NK cells revealed that 89Zr-PS-H resulted in higher cellular retention of radioactivity compared to both89Zr-PS. There was no significant labeling of the cells using the Zr89-only condition.

This study indicates that: (1) human NK cells are most effectively labeled with 89Zr -PS-H mixtures in the absence of serum. (2) An optimized NK cell labeling was achieved with an incubation time of 30 min without posing significant adverse effects on cell viability or phenotypic changes.

NK cells can be successfully labeled in vitro with 89Zr (T1/2=78h) under suitable conditions and this method may enable in vivo dynamic imaging of NK cells over a period of days using serial PET scan.

Aras, O, Berg, M, Pantin, J, Szajek, L, Paik, C, Frank, J, Sato, N, Childs, R, Choyke, P, Labeling of NK Cells with 89Zr for Positron-Emission Tomography (PET) Imaging: A New Method for in Vivo Cell Tracking.  Radiological Society of North America 2012 Scientific Assembly and Annual Meeting, November 25 - November 30, 2012 ,Chicago IL. http://archive.rsna.org/2012/12037076.html