Injection of Cells and Monoclonal Antibodies into Mice: Comparison of Tail Vein and Retroorbital Routes 1

Abstract

Organ distribution and blood concentration profiles were compared following injection of mice with radiolabeled test agents via the lateral tail vein or retroorbital venous sinus. Monoclonal antibodies directed against B16 melanoma of C57BL/6 origin were labeled with iodine-125. Thymocytes from BALB/c mice and B16 melanoma cells were labeled with technetium-99m sodium pertechnetate (Na ^99mTcO₄). Animals were injected with 5 μCi of iodinated antibody, 5 × 10⁵ syngeneic thymocytes, 2.5 × 10⁵ melanoma cells, or 10 μCi Na ^99mTcO₄ in 0.2 ml saline via either route. In non-tumor-bearing C57BL/6 mice radiolabeled monoclonal antibody was found primarily in the gastrointestinal tract, liver, and blood. Na ^99mTcO₄ localized in the gastrointestinal tract, ^99mTc-labeled thymocytes in the spleen and liver, and ^99mTc-labeled B16 melanoma cells in the liver and lungs. Pharmacokinetic analysis of blood samples taken 4, 8, and 12 min following injection of the labeled agents suggested that the iodinated antibody had less vascular permeability than Na ^99mTcO₄ and that thymocytes and B16 melanoma cells were trapped in the pulmonary vasculature as they passed through the lungs. It is noteworthy that no biologically significant differences in organ distribution patterns or blood decay profiles were found between lateral tail vein and retroorbital routes. The data clearly indicate that these routes can be used interchangeably with one another for intravenous injections.