抗CD20单克隆抗体诱导B淋巴瘤细胞株凋亡的实验研究

本研究探讨抗CD20单克隆抗体体外诱导B淋巴细胞株凋亡情况及其可能的作用机制。体外培养Daudi、Ramos、Namalwa和Raji细胞，采用XTT法测定细胞增殖抑制率；用流式细胞术测定细胞凋亡；Western blot测定Daudi、Ramos、Raji和Namalwa细胞经Rituximab 20μg／ml作用24小时后Bcl-2的表达情况。结果表明：抗cD20单克隆抗体对Daudi、Raft和Namalwa淋巴瘤细胞有轻度的抗增殖作用，对Ramos细胞无抗增殖作用，抗增殖作用与单克隆抗体作用浓度无关。抗CD20单克隆抗体对4株细胞无明显诱导凋亡作用，抑制率在3％-10％之间波动。Na—malwa和Raji细胞株经抗CD20单克隆抗体作用24小时后，Bcl-2蛋白表达下调。结论：单药抗CD20单克隆抗体对Daudi、Namalwa和Raji细胞株有轻度抗细胞增殖作用，但与作用浓度和作用时间无明显相关。单药抗CD20单克隆抗体对Daudi、Namalwa、Raji和Ramos细胞株有微弱的诱导凋亡作用。Namalwa和Raji细胞株经抗CD20单克隆抗体作用24小时后Bcl-2表达下调，这可能是抗CD20单克隆抗体增敏细胞毒药物作用的机制之一。

Preclinical Study of Apoptosis of B-NHL Cell Lines Induced by Anti-CD20 Monoclonal Antibody

The aim of this study was to investigate the effect of anti-CD20 monoclonal antibody （McAb） on induction of apoptosis in malignant B cell lines in vitro and to explore its possible mechanism. The human Burkitt＇ s lymphoma cell lines （Daudi, Namalwa, Raji and Ramos cells ） were cultured in vitro. The inhibitory rate of cell proliferation was detected by XTT assay, the apoptosis of cells was determined by flow cytometry. The expression of BCL-2 in human Burkitt＇s lymphoma cell lines （Daudi, Namalwa, Raji and Ramos cells） treated with rituximab（20 μg/ml） for 24 hours was analyzed by Western blot. The results showed that the anti-CD20 McAb had a slight antiproliferation effect on the Daudi, Namalwa, Raji cell lines and no effect on the Ramos cell line. There is no correlation between the effect and the concentration of anti-CD20 McAb. Anti-CD20 McAb as a single agent could weakly induce the apoptosis of four cell lines. The inhibitory rate of cell proliferation ranged from 3% to 10%. Expression of BCL-2 protein was down-regulated after treated by anti-CD20 McAb for 24 hours in Raji and Namalwa cell lines. It is concluded that the anti-CD20 McAb as a monomer can slightly inhibit the proliferation of Daudi, Namalwa and Raji cell lines, the inhibition does not dependent on the treating time and the concentrations of anti-CD20 McAb. Anti-CD20 McAb as a monomer can weakly induce the apoptosis of four cell lines. Expression of BCL-2 in Raji and Namalwa cell lines is down-regulated after the cells were treated by anti-CD20 McAb for 24 hours. Down-regulation of BCL-2 expression may be one of the mechanisms enhancing the cytotoxicity of cytotoxic drugs.