Important Chemical Variables for Labeling Antibodies with Indium-111 and Technetium-99m
The use of radiolabeled antibodies for radioimmunodetection of malignant tumors involves research in several disciplines such as chemistry, immunology and pharmacokinetics. Each of these areas has to be investigated systematically to guarantee a successful radioimmunodetection technology. This paper focuses its discussion primarily on chemical and immunochemical aspects associated with radiolabeling of antibodies with In-111 and Tc-99m. A bifunctional chelate approach using a cyclic DTPA dianhydride is used as a model reaction for the indirect labeling of antibody and antihuman serum albumin antibody is used as a model antibody. The optimization of important chemical parameters is discussed for the conjugation and labeling reactions. The relationship between the number of DTPA groups and the antibody immunoreactivity is also discussed.
KeywordsConjugation Reaction High Affinity Site Conjugation Yield DTPA Concentration Stannous Tartrate
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