在小鼠异基因骨髓细胞移植中超抗原SEB诱导的耐受特征

Characteristics of staphylococcal enterotoxin B (SEB)-induced anergy in transplantation of allogeneic bone marrow cells

目的: 研究在异基因骨髓细胞移植中葡萄球菌肠毒素B(SEB)诱导的耐受强度和细胞学特征.方法: 选用C57BL/J小鼠作为受体,BALB/c小鼠作为供体.所有受体小鼠在接受6×107骨髓细胞前均接受6.0Gy 60Coγ射线的照射,随机分成3组: 组1为只接受6.0Gy 60Coγ射线照射的对照组(照射对照组,RI);组2为照射后注射生理盐水(移植对照组,Tran.); 组3为照射后注射60 μg SEB(SEB组).180 d后由组2和组3实验鼠获得两组C57BL/L-BALB/c嵌合体小鼠.用流式细胞术分析移植后30～180d受体小鼠体内CD4+ T、 CD8+ T、 CD3+/NK1.1+ NKT淋巴细胞亚群的数量和MHC H-2Kb、 H-2Kd抗原表达的百分率,用MLR方法测定嵌合体小鼠淋巴细胞对ConA和异源性抗原的反应性.结果: (1)接受大剂量骨髓细胞移植后,注射SEB和注射生理盐水的两组小鼠均可存活180 d以上,SEB组小鼠呈现出BALB/c供体小鼠的颜色特征(白色);Tran.组小鼠呈现出其灰白色.(2)SEB组嵌合体小鼠对ConA的反应性明显低于RI组和Tran.组;对异源性抗原的应答高于Tran.组.(3)SEB组小鼠外周血中CD4+ T细胞的数量在移植后30～60 d明显下降,随后增加; CD8+T细胞的数量不变.CD3+/NK1.1+ NKT细胞的数量,从接受移植后30 d开始增加,随着时间的延长而递增,到180d达到5.71%.存活180 d的嵌合体小鼠,体内供体小鼠特有的MHC H-2Kd抗原的表达率高达80.95%,自体MHC H-2Kb抗原表达的百分率只占1.45%.(4)与SEB组相反,Tran.组小鼠CD8+ T细胞的数量持续下降; CD3+/NK1.1+NKT细胞的数量的增加只在移植后180 d上升达到5.07%.结论: 在异基因骨髓细胞移植中,SEB诱导的耐受性比单纯骨髓移植诱导的耐受性强.SEB诱导的耐受性与移植早期特异性CD4+ T细胞数量的减少和NKT细胞数的持续增加有关.反应性的降低表现为T细胞对ConA反应性的下降.

AIM： To investigate the characteristics of the SEB-induced anergy in transplantation of allogeneic bone marrow cells, METHODS： C57BL/J （recipients） and BALB/c （donors） mice were used in this study. The recipients were irradiated with 6.0Gy^60Co-γ-ray followed by transplantation of allogeneic bone marrow cells （ 6 × 10^7 ）. The recipients treated with ^60Co-γ-ray were then divided into 3 groups; Group 1 treated with ^60Co-γ-ray （ RI control group）, and group 2 （transplantation control group） and group 3 （ SEB experiment group） received saline or 60 μg SEB after the transplantation of bone marrow cells. T cell subtypes and expression of MHC molecules were detected by flow cytometry. Proliferation of lymphocytes in response to ConA and allogeneic antigen were examined by MLR. RESULTS： （ 1 ） The recipients treated with and without SEB survived for at least 180 days and became chimeric with while hair color （the donors＇ color）. （2） SEB inhibited proliferation of lymphocytes in the recipients in response to ConA but not to allogeneic antigen as compared with that in the Group 1 and Group 2 mice. （3） The CD4^＋ T but not CD8^＋ T cells in the recipients treated with SEB were decreased from day 30 to day 60 after transplantation. （4） With the treatment of SEB. frequency of CD3^＋/NK1. 1^＋ NKT cells was increased to5,71% on day 180, In the recipients, the expression of do- nor＇s MHC H-2K~ were inhanced 80. 95% and self MHC H-2K^b expressed 1.45% only, CONCLUSION： SEB can induce a stronger anergy than that induced by irradiation, SEB-induced anergy is related with the reduction of CD4^＋ T cells and an increase in CD3^＋/NK1. 1^＋ NKT cells at the early phase of transplantation, T cells were showed specific down-regulation in this study.