CD28、CD40通路共刺激对淋巴细胞增殖反应的影响及CsA的抑制作用

目的：探讨CD28、CD40通路共刺激后淋巴细胞增殖反应的变化及免疫抑制剂环孢素A(CsA)、抗CTLA4单克隆抗体对共刺激通路激活后淋巴细胞增殖反应的影响。方法：采用单克隆抗体与淋巴细胞表面CD3、CD28及CD40L分子结合产生相应刺激信号，根据刺激条件不同设组为：①抗CD3单抗单刺激(A组)(剂量为10μg／L、100μg／L、1000μg,／L)；②抗CD3单抗 抗CD28单抗(B组)；③抗CD3单抗 抗CD40L单抗(C组)；④抗CD3单抗 抗CTLA4单抗(D组)共刺激(A、B、C、D组中抗CD3单抗剂量固定为100μg／L，其余3种单抗各设10μg／L、100μg／L、1000μg／L3种剂量)；⑤抗CD3单抗 抗CD28单抗 抗CD40L单抗(E组)；⑥抗CD3单抗 抗CD28单抗 抗CTLA4单抗(F组)共刺激(E、F组中抗CD3单抗和抗CD28单抗的剂量固定为100μg／L，抗CD40L单抗和抗CTLA4单抗的剂量各设10μg／L、100μg／L、1000μg／L)；⑦CsA干预组：抗CD3单抗 CsA(G组)；⑧抗CD3单抗 抗CD28单抗 CsA(H组)；⑨抗CD3单抗 抗CD28单抗 抗CD40L单抗 CsA(I组)，G、H、I组中所有单抗浓度均固定为100μg／L，CsA浓度设为10μg／L、100μg／L、1000μg／L。采用^3H]-TdR同位素掺人法测定淋巴细胞增殖水平，液体闪烁计数仪测定放射性计数值。结果：用抗CD3单抗 抗CD28单抗共刺激后，淋巴细胞增殖反应明显高于抗CD3单刺激，而在抗CD3单抗 抗CD40L单抗刺激组，淋巴细胞增殖反应低于抗CD3单刺激组。抗CTLA4单抗所提供的刺激信号可抑制抗CD3单刺激及抗CD3 抗CD28共刺激导致的淋巴细胞增殖反应，并且随着抗CTLA4单抗剂量的增加，抑制作用增强。CsA对共刺激后的淋巴细胞增殖反应有抑制作用，且随着剂量增大其抑制作用也增强，但对单刺激后增殖反应的抑制作用更为明显。结论：CD28共刺激通路在淋巴细胞活化中起着关键作用。抗CD40L单抗的刺激作用可能被其对T细胞与抗原递呈细胞(APC，包括B细胞等)间的阻断效应所掩盖。抗CTLA4单抗及CsA对共刺激后淋巴细胞的增殖反应均有抑制作用。

Effects of cyclosporin A on CD28/CTLA4 and CD40/CD40L co-stimulated lymphocyte proliferation

Aim: To investigate the effects of cyclosporin A(CsA)and anti CTLA4 monoclonal antibody(mAb) on CD28 and CD40 co stimulated lymphocyte proliferation. Methods:By using human lymphocyte culture system, the lymphocyte proliferation was examined by method of TdR isotope absorption. The experimental groups were divided into CD3 mAb (group A );CD3 mAb+CD28 mAb (group B);CD3 mAb+CD40 L mAb (group C);CD3 mAb+CTLA4 mAb (group D );CD3 mAb+CD28 mAb+CD40L mAb (group E );CD3 mAb+CD28 mAb+CTLA4 mAb (group F);CD3 mAb+CsA (group G );CD3 mAb+CD28 mAb+CsA(group H); CD3 mAb+CD28 mAb+CD40L mAb+CsA (group I). Results:The lymphocyte proliferation in group of anti CD3 mAb+anti CD28 mAb co stimulation was highly increased compared with that in group of anti CD3 mAb stimulation while that was decreased in group of anti CD3 mAb+anti CD40L co stimulation. CsA as well as anti CTLA4 mAb inhibited the lymphocyte proliferation induced by anti CD3 mAb stimulation and anti CD3 mAb+anti CD28 mAb co stimulation. The inhibitory effect of CsA on CD3 mAb stimulated lymphocyte proliferation was more significant. Conclusion: CD28 co stimulatory pathway plays a key role in lymphocyte activation. The stimulatory effects of anti CD40L mAb on lymphocyte proliferation may be concealed by its blockade of interaction between T lymphocyte and antigen presenting cell(APC, including B cells). CsA and CTLA4 mAb can inhibit co stimulated lymphocyte proliferation.