一株识别肿瘤细胞上CD40突变体分子的单克隆抗体的研制及其生物学功能研究

Preparation and characterization of a mouse anti-human CD40 mutant monoclonal antibody

目的:以本科室发现肿瘤细胞上表达的CD4078AA突变为基础,研制识别肿瘤细胞上CD40突变体分子的单克隆抗体(mAb),并对其生物学特性作初步分析。方法:以转人CD40突变体转基因细胞L929-CD40mu为免疫原,免疫6～8周龄的雌性BALB/c小鼠;采用B淋巴细胞融合技术,将免疫小鼠脾脏细胞与Sp2/0融合,以L929-CD40mu转基因细胞为抗体筛选阳性细胞,免疫荧光标记法对杂交瘤进行反复筛选和多次的克隆化培养;采用快速定性试纸法及竞争抑制结合试验分析该mAb的亚类及抗原识别位点;免疫印迹法对该mAb进行鉴定;采用MTT法分析mAb在体外对肿瘤细胞的抑制增殖效应以及PI-annexinⅤ方法进行细胞凋亡测定。结果:获得1株稳定分泌鼠抗人CD40mumAb的杂交瘤细胞株(命名为10C5),该mAb能特异性地识别人肿瘤细胞株HO8910表达的CD40突变体分子,而不识别正常扁桃体B淋巴细胞及血管内皮细胞表达的CD40分子,并且能够在体外促进肿瘤细胞凋亡。结论:成功地研制出1株特异性识别肿瘤细胞上CD40突变体分子的mAb,该mAb具有体外抑制肿瘤细胞生长并促进其凋亡的作用。

AIM： To prepare and characterize a mouse anti-human CD40 mutant monoclonal mAb. METHODS： Female BALB/c mice of 6 -8 weeks old were immunized with CD40 mutant transfectant （L929-CD40mu） as immunogen, The spleen B cells of the mice were fused with Sp2/0 myeloma cells. The hybridoma cells were screened with CD40 mutant transfectant （L929-CD40mu） by FCM. Faststrip analysis was performed to identify Ig subclass of this mAb. The epitope recognized by this mAb was detected by Bio-5C11 competitive assay. Western blot technique was adopted to identify the mAb. The proliferation of tumor cells in vitro was analyzed by MTT assay and apoptosis of tumor cells in vitro was analyzed by PI-annexin V assay. RESULTS. One hybridoma cell line named 10C5 was obtained, which had the property of secreting anti-human CD40 mutant monoclonal antibody continuously and steadily. This mAb specifically recognized human CD40 mutant molecule and induced the apoptosis of tumor cells in vitro. CONCLUSION： One hybridoma cell line which can secret a mouse anti-human CD40 mutant mAb has been prepared successfully. This mAb can inhibit the growth of tumor cells expressing CD40 mutant and induce their apoptosis in vitro.