In vitro cytotoxicity of 131I-Rituximab against B-cell lymphoma cells / 南方医科大学学报

ABSTRACT

<p><b>OBJECTIVE</b>To study the specific cytotoxicity of (131)I-Rituximab against CD20-positive B-cell lymphoma cells.</p><p><b>METHODS</b>Rituximab was labeled with (131)I using IODO-GEN method, and the dose-effects of various concentrations of (131)I-Rituximab, (131)I alone and Rituximab in Raji cells were evaluated by MTT assay to determine the optimal dose according to the dose-effect curves. The cytotoxicity of (131)I-Rituximab, (131)I and Rituximab was assessed in CD20-positive Ramos (RA-1) cells, Raji cells and CD20-negative Molt-4 cells according to the changes of the survival rates. Giemsa staining was used to evaluate the antitumor effect of (131)I-Rituximab in Raji cells by measuring the mitosis index (MI).</p><p><b>RESULTS</b>(131)I-Rituximab presented with a dose-dependent cytotoxicity against Raji cells. At the specific activity of 60 microCi/ml, (131)I-Rituximab resulted in significantly higher growth inhibition rate of the cells than Rituximab (P<0.05). The inhibition rate of Raji cells treated with (131)I-Rituximab, (131)I, or Rituximab for 96 h were comparable with the rates in Ramos RA-1 cells, but significantly higher than the rates in Molt-4 cells. The MI values in (131)I-Rituximab group were significantly lower than those in the other groups (P<0.001).</p><p><b>CONCLUSION</b>(131)I-Rituximab can induce specific cytotoxicity against CD20-positive tumor cells, and may potentially serve as an agent for targeted radioimmunotherapy for CD20-positive B-cell lymphoma.</p>