The Distribution of Halogenated (At-211 or I-125) Tumor Specific Antibody in Tumor Bearing and Control Mice
In radioimmunotherapy, utilization of the high, cell sterilizing capability of the α particles emitted by the short-lived (T = 7.21 hr) halogen, astat ine-211, would be possible if the antibody reached and penetrated the tumor within a few hours of administration. These requirements might be fulfilled where small clusters of tumor cells exist and where an antibody is directed against an unshed membrane antigen rather than a secreted antigen. A murine, Thy 1.1, T cell lymphoma in an advanced stage of development in Thy 1.2 mice, is being used as a tumor model to investigate the uptake by a tissue and spatial distribution within that tissue of a radiohalogenated (At-211 or I-125) anti-Thy 1.1 monoclonal antibody 4 hr after intravenous administration.
At this time, the concentration of labeled antibody in the blood of the tumor bearing mice is 1/10 that in the control normal Thy 1.2 mice (in which there are no Thy 1.1 receptors) and 1/5 that in the control normal Thy 1.1 mice (in which the Thy 1.1 receptors are present naturally). Autoradiographs (ARG’s) of the spleen at 4 hr after injection show complete penetration by the antibody of the tumor infiltrated areas with a high density of grains, confined to those areas and not over normal lymphocytes. By comparison, the distribution of antibody in the spleen of control Thy 1.2 mice is homogeneous and the grain density is low.
KeywordsA120 Cell Tumor Bear Mouse Label Antibody Tumor Bearing White Pulp
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