B 淋巴细胞在抗 CD45 RB 抗体诱导的移植免疫耐受中的作用

摘要

AIM:To investigate the role of B cells in CD45RB antibody-induced transplantation immune toler-ance.METHODS:Single cell suspension was made from the spleen of BALB/c nude mice disposed by CD45RB antibod-y, then mixed cultured with T cells of BALB/c mice and spleen cells of C57BL/6 mice.The Th1, Th2, Treg and Tm cells were monitored by flow cytometry during the culture process .The skin graft model was set up with B 6.μMT-/-mice as re-ceptors and BALB/c mice as donors.CD45RB antibody was intraperitoneally injected into the receptors after transplantation and then CD3+CD45RBhi cells were detected by flow cytometry .In another mixed lymphocyte culture , CD45RB antibody was added, and then B cells were isolated and injected into B6.μMT-/-mice through the tail vein.The heart transplanta-tion model was established with B 6.μMT-/-mice as receptors and BALB/c mice as donors, and then the survival and the migration of B cells to the thymus were observed .RESULTS:When T lymphocytes were co-cultured with B lymphocytes treated with anti-CD45RB monoclonal antibody (mAb) in vivo, the percentages of Th2 and Treg cells were up-regulated and Th1 cells were down-regulated, but Tm cells were not altered as compared with the control .In vivo without B lympho-cytes, anti-CD45RB mAb also down-regulated the expression of CD45RB in T lymphocytes.The reduction was faster and the percentage of CD3 +CD45RBhi T cells was not altered as compared with the control .The B lymphocytes treated with an-ti-CD45RB mAb in vitro prolonged the lifetime of receptor in heart transplantation model but failed to induce complete toler -ance.After recieving B cells treated with anti-CD45RB mAb and allogeneic heart transplantation , B cells migrated to the thymus in B6.μMT-/-mice.CONCLUSION:B lymphocytes play a definite role in the transplantation immune tolerance induced by anti-CD45RB mAb through their affection on T-cell subgroups and also in the central tolerance .However, the induction of immune tolerance can not only rely on B cells .%目的：探讨B淋巴细胞在抗CD45RB抗体诱导的移植免疫耐受中的作用。方法：抗CD45RB抗体对BALB／c裸鼠进行预处理后制备脾脏单细胞悬液，与BALB／c小鼠T淋巴细胞和C57BL／6小鼠脾细胞混合培养，流式细胞术分析Th1、Th2、Treg和Tm淋巴细胞。以B6．μMT－／－小鼠为受体、BALB／c小鼠为供体建立皮肤移植模型，移植后向受体鼠腹腔注射抗CD45RB单抗，监测脾淋巴细胞CD3＋CD45RBhi细胞比例。在混合淋巴培养过程中加入抗CD45RB单抗，分离B 细胞，建立以BALB／c 小鼠为供体、B6．μMT－／－小鼠为受体的心脏移植模型，通过尾静脉注射B细胞给B6．μMT－／－小鼠，观察受体鼠生存期和B细胞分布。结果：在裸鼠体内用抗 CD45RB 抗体处理过的B淋巴细胞，与T淋巴细胞混合培养时，可使Treg和Th2淋巴细胞比例明显升高，Th1淋巴细胞的比例明显下降，Tm细胞无明显变化。在体内B淋巴细胞缺失的情况下，抗CD45RB抗体依然能够降低T细胞表面CD45RB的表达，与对照组B淋巴细胞存在组相比，抗 CD45RB 抗体对 T 淋巴细胞表面 CD45RB 下调更为快速，但最终CD3＋CD45RBhi T细胞比例无明显变化。体外抗CD45RB抗体处理过的B淋巴细胞可以延长受体鼠的生存时间。B6．μMT－／－鼠在接受抗CD45RB抗体处理的B细胞并进行同种异体心脏移植后，B细胞可向胸腺迁移。结论：在抗CD45RB抗体诱导的免疫耐受中，B淋巴细胞可能通过介导各T淋巴细胞亚群比例发挥着重要作用，且在中枢耐受中也起到一定作用，但是仅靠B淋巴细胞无法形成完全耐受。