Use of new heterobifunctional reagent for radiometallic labeling of antibodies.
A new heterobifunctional reagent, 2,6-dioxo-N-(carboxymethyl)morpholine (DCM), was synthesized, reacted with a monoclonal antibody (MAb) to human high-molecular-weight, melanoma-associated antigen, and then chelated with 111In. The same MAb also was chelated with 111In with the use of the bicyclic anhydride of pentetic acid (BADTPA), a homobifunctional reagent, for comparative studies. The labeling efficiencies were similar: an average of 79% for 111In-iminodiacetic acid-MAb and an average of 75% for 111In-DTPA-MAb. However, the loss of immunoreactivity was 32.6% and 58.7% for both radiolabeled antibodies, respectively. Analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis demonstrated a high-molecular-weight polymer band only for the 111In-DTPA-MAb preparation. The results indicate that DCM likely causes less denaturation of antibody by eliminating the cross-linking reaction that is known to occur with homobifunctional chelating reagents.
D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm / Q000276:immunology; D002460:Cell Line; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D007204:Indium; D007553:Isotope Labeling; D008545:Melanoma / Q000276:immunology*; D009025:Morpholines / Q000138:chemical synthesis; D011868:Radioisotopes
D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm; D009025:Morpholines; D011868:Radioisotopes; D007204:Indium; C051461:2,6-dioxo-N-(carboxymethyl)morpholine