^(131)I-Rituximab对B细胞淋巴瘤细胞杀伤效应的实验研究

In vitro cytotoxicity of ^(131)I-Rituximab against B-cell lymphoma cells

目的研究131I标记的Rituximab对CD20表达阳性的B细胞淋巴瘤细胞的特异性杀伤作用,为放射免疫导向治疗提供实验依据。方法应用IODO-GEN法对Rituximab进行131I标记,以MTT比色法测定131I-Rituximab、131I和Rituximab对Raji细胞的剂量效应曲线,并根据剂量效应曲线选取合适的剂量,以131I-Rituximab、131I及Rituximab作用于CD20阳性的RamosRA-1细胞、Raji细胞以及CD20阴性的Molt-4细胞,根据细胞存活率的变化,评价131I-Rituximab、131I及Rituximab对上述细胞的杀伤作用。Gimesa染色观察核分裂指数(MI值)等指标评价131I-Rituximab对Raji细胞的抗肿瘤活性。结果131I-Rituximab对Raji细胞的杀伤作用呈剂量依赖性;选取60μCi/ml作为疗效实验的作用剂量,131I-Rituximab组的细胞抑制率显著高于Rituximab组(P<0.05)。Raji细胞在131I-Rituximab、131I、Rituximab作用96h后的细胞抑制率,与同等条件下的Ramos(RA-1)细胞比较,无显著性差异(P>0.05);与同等条件下的Molt-4细胞比较,均显著增高(P<0.05)。④131I-Rituximab的MI值最低,与其他各组比较有显著性差异(P<0.001)。结论131I-Rituximab可特异性杀伤CD20表达阳性的肿瘤细胞,为放射免疫治疗CD20阳性的B细胞淋巴瘤提供可能性。

Objective To study the specific cytotoxicity of ^131I-Rituximab against CD20-positive B-cell lymphoma cells. Methods Rituximab was labeled with ^131I using IODO-GEN method, and the dose-effects of various concentrations of ^131I-Rituximab, ^131I alone and Rituximab in Raji cells were evaluated by MTT assay to determine the optimal dose according to the dose-effect curves. The cytotoxieity of ^131I-Rituximab, ^131I 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 anfitumor effect of ^131I-Rituximab in Raji cells by measuring the mitosis index （MI）. Results ^131I-Rituximab presented with a dose-dependent eytotoxicity against Raji cells. At the specific activity of 60 μCi/ml, ^131I-Rituximab resulted in significantly higher growth inhibition rate of the cells than Rituximab （P〈0.05）. The inhibition rate of Rail cells treated with ^131I-Rituximab, ^131I, or Rituximab for 96 h were comparable with the rates in Ramos RA-1 ceils, but significantly higher than the rates in Molt-4 cells. The MI values in ^131I-Rituximab group were significantly lower than those in the other groups （P〈0. 001）. Conclusion ^131I-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.