移植免疫耐受中调节性B细胞与调节性T细胞的依赖性关系研究

Dependence relationship between regulatory B cells and regulatory T cells in transplantation immune tolerance

目的探讨在联合抗Tim-1/抗CD45RB抗体诱导的移植耐受中调节性B细胞(Bregs)与调节性T细胞(Tregs)的关系。方法建立BALB/c小鼠到C57BL/6小鼠的同种胰岛移植长期耐受模型,将长期耐受小鼠(LTS)的B细胞过继输注至接受胰岛移植的B细胞缺陷小鼠(μMT-/-)体内,或加用抗CD25抗体(PC61)去除CD25+Treg细胞,观察移植物的存活时间,用流式细胞仪检测Foxp3+Treg数量变化。将CD4+Foxp3-GFP-T细胞与Bregs细胞联合过继输注RAG小鼠体内,检测Foxp3+GFP+T细胞的扩增情况。建立小鼠皮肤移植模型,在双抗体治疗的同时加用抗CD20抗体祛除B细胞,观察对Tregs数量的影响。结果继承性转移长期耐受小鼠的Bregs可诱导83.3%的小鼠长期耐受,但加用抗CD25单抗后,胰岛移植物在较短时间(MST=20d)内全部被排斥;继承性转移长期耐受小鼠Bregs可使Tregs数量明显增加(P<0.01),并且可诱导CD4+Foxp-T细胞表达Foxp3;用抗CD20抗体祛除B细胞后,双抗体诱导的皮肤移植受体小鼠体内Tregs数量明显减少(P<0.01)。结论在双抗体诱导的移植耐受中,Bregs可能通过促进Tregs生成而延长移植物的存活。

Objective To investigate the relationship between regulatory B cells（Bregs）and regulatory T cells（Tregs）in transplantation tolerance induced by dual anti-CD45RB/anti-TIM-1antibody.Methods The longterm murine islet allograft transplant models from BALB/c to C57BL/6were established.B cells purified from longterm survivors（LTS）were adoptively transferred to grafted B cell-deficientμMT-/-B6 recipients and treated with or without PC61.The allograft survival time was analyzed and the number of Foxp3＋Treg cells was examined by flow cytometry.Murine skin allograft transplant models was established and treated with dual antibody.The change of the percentage of Treg cells was observed after B-cell depletion using anti-CD20 antibody.Results Adoptive transfer of Bregs in longterm tolerated murines could induce longterm tolerance in 83.3% of murines.But after adding CD25 m monoclonal antibody,islet grafts were completely rejected in a short time（MST=20d）;adoptive transfer of Bregs in longterm tolerated murines could increase the Tregs number（P〈0.01）,moreover could induce CD4＋Foxp-T cell to express Foxp3;after deleting B cells with CD20 antobody,Tregs cells number in the skin transplant recipient murine induced by dual antibody was remarkably reduced（P〈0.01）.Conclusion In transplantation tolerance induced by dual antibody,Breg cells may prolong the graft survival time possibly through promoting Treg generation.