The processing and fate of antibodies and their radiolabels bound to the surface of tumor cells in vitro: A comparison of nine radiolabels
- Univ. of South Carolina, Columbia, SC (United States)
Processing radiolabeled degradation products is the key factor affecting retention of antibodies within the cell. In this study, the authors have analyzed the processing of antibodies labeled in nine different ways. Antibodies were labeled with three different radioisotopes and seven different forms of {sup 125}I. Eight of the radiolabels (except {sup 188}Re) were conjugated to the same antibody, MA103, and tested on the renal carcinoma cell line SK-RC-18 and/or the ovarian carcinoma cell line SK-OV-6. Rhenium conjugation utilized the antibody RS7, the target cell line ME180 and three of the other radiolabels were also tested with this antibody-target cell combination for comparison. Iodine conjugated to antibodies by conventional methods was rapidly released from the cell after antibody catabolism. In contrast, iodinated moieties, such as dilactitol-tyramine and inulin-tyramine were retained within cells four to five times longer. The use of radiolabels that are trapped within cells after antibody catabolism can potentially increase the dose of radiation delivered to the tumor, from the same amount of radioactivity deposited by a factor of four or five. The prolonged retention of {sup 111}In relative to {sup 125}I is not due to deiodination of iodine conjugates, but rather to intracellular retention of catabolic products containing {sup 111}In, perhaps within lysosomes. 45 refs., 4 figs., 1 tab.
- OSTI ID:
- 95914
- Journal Information:
- Journal of Nuclear Medicine, Vol. 35, Issue 5; Other Information: PBD: May 1994
- Country of Publication:
- United States
- Language:
- English
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