动物造模,靶向淋巴瘤 z-bio 2021-07-14 547

　　Objective: To establish a CD45 monoclonal antibody-mediated two-step pre-positioning method for 188e-avidin, observe its biological distribution characteristics in cancer-bearing mice, and evaluate its feasibility in the treatment of lymphoma.

　　Method: CD45 monoclonal antibody and avidin were respectively labeled with 188Re direct labeling method and paper chromatography method to determine the labeling rate and radiochemical purity. Six Nod-Scid mice transplanted with human Raji cells were randomly divided into two groups, the experimental group was a two-stage pre-preparation group, and the control group was a 188e-CD45 monoclonal antibody group. SPECT imaging was performed 0.5, 1, 6, and 23 hours after injection. At the same time, two groups of tumor-bearing mice were sacrificed 24 hours after injection, organ tissues and tumors were taken, weighed, and radioactivity counts were determined. Compensation for radioactive decay Calculate the ?D/g and target/non-target (T/NT) ratio for each organ.

　　Results: The labeling rate of 188Re-CD45 monoclonal antibody is (82.52±2.92)? The radiochemical purity is → 90? The average labeling rate of 188Re-avidin is (80.83±3.48)? SPECT imaging and in vivo biodistribution of cancer-bearing mice The results showed that during the entire imaging period of the experimental group, the radioactivity in the blood pool was lower, while the radioactivity levels in the liver and spleen were higher. The radioactivity distribution increases in long-term tumors. The tumor becomes obvious within 1-6 hours and lasts up to 23 hours. Twenty-four hours after the injection of the marker, tumor uptake (?D/g) was (1.34±0.52)? Kidney and liver uptake (?D)/g) were (6.77±2.32)? (2.81), respectively, ± 1.25)? The %ID/g of other organs remained low, the tumor/blood ratio was (4.28±0.82) for 24 hours, and the tumor/muscle ratio was (8.00±0.88). In the control group, the liver, spleen, and kidney had obvious accumulation of radioactivity, and the tumor site was blurred. There was more radioactivity distribution in the blood pool at 20 hours, and a small amount of radioactivity accumulation was visible. it is. Tumor site: 24 hours after the injection of the marker, the tumor/blood ratio was (0.58±0.06), and the tumor/muscle ratio was (3.21±0.24).

　　Conclusion: Compared with the 188Re-CD45 monoclonal antibody group, the CD45 monoclonal antibody-mediated 188Re-avidin 2-step pre-targeting group has better specificity and targeting in lymphoma-bearing mice. The T/NT ratio of the tumor increased significantly. , And the tumor can be seen 1 hour after the injection of the marker.