Journal of the National Cancer Institute
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J. Natl. Cancer Inst. · Nov 1987
An immunotoxin composed of a monoclonal antitransferrin receptor antibody linked by a disulfide bond to the ribosome-inactivating protein gelonin: potent in vitro and in vivo effects against human tumors.
An immunoconjugate was prepared containing a disulfide linker between a murine monoclonal antibody (5E9), which recognized the human transferrin receptor, and the ribosome-inactivating protein gelonin. This immunoconjugate was found to consist of two major species, 5E9-gelonin2 and 5E9-gelonin1, and a minor species of 5E9-gelonin3 and less than 10% of either free antibody or gelonin. 5E9-gelonin was extremely toxic in vitro to human tumor cell lines expressing the 5E9 antigen, including a Burkitt's lymphoma, an adult T-cell acute lymphocytic leukemia, an acute myelogenous leukemia, a promyelocytic leukemia, and a cervical carcinoma line. A 24-hour exposure to 10(-9) M immunoconjugate killed 90-99.9% of tumor cells, depending on the cell line. ⋯ The 5E9-gelonin conjugate, when administered iv at the time of ip tumor inoculation, prolonged survival of nude mice bearing Namalwa or other human tumors as ascites xenografts and delayed or prevented the growth of subcutaneous nodules of Namalwa in an antigen-specific fashion after a single iv injection. Direct intratumoral administration also inhibited the growth of visible subcutaneous nodules of Namalwa. This immunoconjugate may be useful in the treatment of human cancer.