中文摘要：

目的探讨抗CD3抗体诱导小鼠T淋巴细胞增殖与活化的机制并观察重组人TACI-Ig融合蛋白（rhTACI-Ig）对其的影响。方法免疫磁珠纯化得到小鼠T淋巴细胞,用抗CD3抗体刺激,同时给予rhTACI-Ig、rhTNFR∶Fc或IgG-Fc。[3H]-TdR参入法检测T细胞增殖能力,流式细胞术检测T细胞亚群比率,Western blot法检测B淋巴细胞刺激因子、BAFF受体（BAFFR）和跨膜激活剂及钙调亲环素配体相互作用分子（TACI）两个受体及IL-2受体（IL-2R）表达水平和NF-κB活性,采用小干扰RNA（siRNA）抑制T细胞BAFFR或TACI的表达。结果抗CD3抗体体外可促进T细胞增殖与活化,BAFF、白细胞介素-2（IL-2）、γ-干扰素（IFN-γ）和转化生长因子-β（TGF-β）分泌,BAFFR、TACI、IL-2R表达升高和NF-κB活性增强（P〈0.05）。RhTACI-Ig（0.1、1、10、100μg/ml）体外给药可抑制抗CD3抗体诱导的T淋巴细胞增殖（P〈0.05）;rhTACI-Ig（1、10、100μg/ml）可明显降低抗CD3抗体诱导产生的细胞因子水平（P〈0.05,P〈0.01）,显著抑制CD4＋CD69＋T细胞、CD4＋CD154＋T细胞比率,提高CD4＋CD62L＋T细胞比率（P〈0.05,P〈0.01）,且rh TACI-Ig（10、100μg/ml）能降低T细胞上BAFFR、TACI、IL-2受体的表达,抑制NF-κB活性（P〈0.05）。沉默BAFFR或TACI对抗CD3抗体诱导的T细胞增殖有抑制作用（P〈0.01）。结论抗CD3抗体部分通过产生BAFF,激活BAFFR信号而促进T细胞增殖与活化,rhTACI-Ig中和BAFF,抑制BAFF相关受体的表达和NF-κB活性,减少T细胞表达IL-2受体,阻止T细胞过度增殖与活化。

英文摘要：

Objective To investigate the molecular mechanism of anti-CD3 antibody induced T lymphocytes proliferation and activation and observe the effect of recombination human TACI-Ig（ rhTACI-Ig）. Methods T lymphocytes were purified from the spleens of mice by immunomagnetic beads and treated with anti-CD3 antibody with or without different concentrations of rh TACI-Ig,recombinant human tumor necrosis factor-α receptor II： Ig G Fc（ rh TNFR： Fc） or Ig GFc. The proliferation of T lymphocytes was determined by [3H]-TdR incorporation,the percentages of T lymphocytes subsets were tested by flow cytometry. Western blot was applied to evaluate the expression of B cell activating factor receptor（ BAFFR）,transmembraneactivator or calcium-modulating cyclophylin ligand-interactor（ TACI）,IL-2 receptor（ IL-2R） and the phosphorylation of NF-κB. Small interfering RNAs were used to block BAFFR or TACI expression. Results Anti-CD3 obviously induced the activation of T lymphocytes,upregulated BAFF,interleukin-2（ IL-2）,interferon-γ（ IFN-γ） and transforming growth factor-β（ TGF-β） secretion,promoted BAFFR,TACI and IL-2R expression,activated NF-κB（ P〈0. 05）. The administration of rh TACI-Ig（ 0. 1,1,10,100 μg / ml） inhibited the proliferation of T lymphocytes induced by anti-CD3 antibody（ P〈0. 05）. Rh TACIIg（ 1,10,100 μg / ml） significantly decreased the production of cytokines（ P〈0. 05,P〈 0. 01）,markedly downregulated the percentage of CD4^＋ CD69^＋ and CD4^＋ CD154^＋ T lymphocytes,elevated the proportion of CD4^＋ CD62L^＋ T lymphocytes（ P 〈0. 05,P 〈0. 01）. Meanwhile,rh TACI-Ig（ 10,100 μg / ml） treatment decreased the level of BAFFR,TACI,IL-2 on T lymphocytes,as well as attenuated the activation of NF-κB（ P〈0. 05）. Depletion of BAFFR or TACI markedly blocked anti-CD3 antibody dependent T cell proliferation（ P〈0. 05,P〈0. 01）.Conclusion Anti-CD3 antibody promotes T lymphocytes activation partially through BAFF production and BAFF recept