Preparation, quality control and biodistribution of 131I-herceptin in New Zealand rabbits / 南方医科大学学报

<p><b>OBJECTIVE</b>To study the immunoactivity,biodistribution and metabolic pattern of (131)I-Herceptin in rabbits.</p><p><b>METHODS</b>Herceptin was radiolabelled with (131)I and its radiochemicalpurity (RCP) measured by size-exclusion high-pressure liquid chromatography (HPLC). The binding rate to BT-474 cells was measured to evaluate the immunoactivity of (131)I-Herceptin. (131)I-herceptin (2.0 mCi/kg) was injected intravenously into New Zealand rabbits. Scintigraphy on emission computed tomography was performed at 3 h, 1, 3 and 5 days after injection, and the radiocounts of the heart, liver and kidney etc. were compared with that of the muscle to calculate the organ-to-muscle activity ratio (O/M). On the fifth day,the rabbits were killed and the blood, myocardium, lung and other organs were obtained for measuring the radiocounts on gamma-counter to calculate the uptake percentage per gram tissue (ID%/g).</p><p><b>RESULTS</b>The labeling rate of (131)I-herceptin was 93% with RCP of 95% and binding rate to BT-474 cells of 36.9%. After injection of (131)I-herceptin, the heart, lung and liver displayed dense radioactive regions but not the muscles and intestines. Three hours after injection, the O/M ratio of the heart was significantly higher than that of the lung, kidney and intestine (P<0.05), but decreased significantly one day after injection (t=10.817, P<0.001) with further decrement on days 3 and 5 (P<0.05). The O/M ratio of liver on day 1, 3, and 5 reduced significantly in comparison with that at 3 h (P<0.05). The uptake percentage was higher in the blood (11.3 ID/g%) than in the liver (2.8 ID/g%) and the myocardium (1.8 ID/g%).</p><p><b>CONCLUSIONS</b>(131)I-herceptin possesses high immunoactivity which distributes mainly in the blood, liver and kidney, but with low uptake in the myocardium.</p>

Adsorption condition optimization for anti-HBsAg Fab fragment separation and purification from E. coli using Streamline SP / 南方医科大学学报

<p><b>OBJECTIVE</b>To optimize the adsorption condition of cation-exchange chromatographic media Streamline SP for separation and purification of anti-HBsAg Fab fragment from E. coli.</p><p><b>METHODS</b>The adsorption of the target protein for separation and purification by the cation-exchange chromatographic media Streamline SP was tested using test tube method in balanced buffer solution with different pH values and ion concentrations. The adsorption effect was then verified by cation-exchange chromatography using 1-ml Streamline SP prepacked column and 28-ml Streamline SP self-assembly column.</p><p><b>RESULTS</b>According to the experiment results of test tube method, the loading buffer with pH of 4.4 and ionic concentration of 100 to 600 mmol/L could achieve optimal target protein adsorption effect by cation-exchange chromatographic media Streamline SP, as verified by cation-exchange chromatography with 1-ml SP prepacked column and 28-ml Streamline SP self-assembly column.</p><p><b>CONCLUSION</b>The optimal condition of cation-exchange chromatography selected by test tube method can be applied for separation and purification of anti-HBsAg Fab fragment from E. coli.</p>

Biological response of B-cell lymphoma cells in vitro to 131I-rituximab / 南方医科大学学报

<p><b>OBJECTIVE</b>To study the biological response of B-cell lymphoma cells positive for CD20 expression to (131)I-labeled rituximab.</p><p><b>METHODS</b>Anti-CD20 monoclonal antibody rituximab was labeled with (131)I by means of IODO-GEN method, and its effects on apoptosis of Raji cells were determined by Annexin-V/PI double-labeled cytometry. Its effects on the cell cycles was evaluated by cytometry with PI staining.</p><p><b>RESULTS</b>The cell apoptosis rate measured by Annexin v-FITC/PI was 51.99% in (131)I-rituximab group, significantly higher than that in (131)I group, rituximab group and control group (42.71%, 29.42% and 26.17%, respectively, P<;0.05). The apoptosis rate by flow cytometry with PI staining was 4.32% in (131)I-rituximab group, also significantly higher than that in the other 3 groups (1.47%, 1.39% and 0.37%, respectively, P<0.05). Cell cycle alteration of Raji cells occurred in (131)I-rituximab group, and the majority of cells were arrested at G(1)/G(2) stage.</p><p><b>CONCLUSION</b>(131)I-rituximab can regulate the cell cycle of Raji cells and induce their apoptosis to inhibit their proliferation.</p>