Radiolabeling of an anti-carcinoembryonic antigen antibody Fab' fragment (CEA-Scan) with the positron-emitting radionuclide Tc-94m.
The goal of this work was to test whether an antibody-based agent approved for use as a single-photon-emitting imaging agent when radiolabeled with technetium-99m could be labeled comparably with a positron-emitting nuclide, technetium-94m. "Instant kits" containing lyophilized NP-4 antibody Fab' fragment of an anticarcinoembryonic antigen IgG (CEA-Scan) from the same manufactured lot were reconstituted with either Tc-99m or Tc-94m, as solutions of sodium pertechnetate in isotonic saline solution. Radioanalyses of the labeled Fab' fragments by size-exclusion high-performance chromatography and TLC were carried out. Equivalent results were obtained for radioimmunoconjugates when each was analyzed with both methods. Facile incorporation of Tc-94m into tumor-targeting Fab' antibody fragments will enable investigation of such agents for tumor-specific imaging using positron emission tomography.
Griffiths
G L
GL
Immunomedics, Inc., Morris Plains, New Jersey 07950, USA.
Goldenberg
D M
DM
Roesch
F
F
Hansen
H J
HJ
D000911:Antibodies, Monoclonal; D002272:Carcinoembryonic Antigen / Q000276:immunology*; D007140:Immunoglobulin Fab Fragments; D007553:Isotope Labeling; D007554:Isotopes; D008982:Molybdenum; D013667:Technetium; D014055:Tomography, Emission-Computed
D000911:Antibodies, Monoclonal; D002272:Carcinoembryonic Antigen; D007140:Immunoglobulin Fab Fragments; D007554:Isotopes; D013667:Technetium; D008982:Molybdenum