TJU103对小鼠同种异基因造血干细胞移植模型GVHD的预防作用

目的探讨TJU103对小鼠同种异基因造血干细胞移植模型移植物抗宿主病(GVHD)是否起预防作用。方法(1)用单向混合淋巴细胞培养方法检测TJU103对T淋巴细胞增殖的影响;(2)以BALB/c(H-2d)、CB6F1(H-2d/b)分别作为完全异基因移植和半相合基因移植的受鼠,给予9.0Gy全身照射后4h,单纯照射组经尾静脉注射0.3mlD-Hank's液,不进行细胞移植;对照组经尾静脉注射C57BL/6小鼠混合细胞悬液(4.5×106骨髓细胞 3.0×107脾细胞),但不进行其他治疗处理;实验组经尾静脉注射C57BL/6小鼠混合细胞悬液(4.5×106骨髓细胞 3.0×107脾细胞) TJU103(终浓度25μg/ml),此后腹腔注射TJU10350μg/d,共7d,然后观察其造血恢复、植入及GVHD的情况。结果(1)TJU103可以显著抑制T细胞活化增殖,其抑制作用呈剂量依赖性,在25μg/ml浓度时,可以抑制83%细胞增殖。(2)由于没有给予GVHD防治措施,对照组受鼠GVHD的发生率和死亡率分别为10/10和10/10;而完全异基因移植实验组小鼠GVHD发生率仅为2/10,30d生存率增加至8/10(P<0.01),中位生存期延长至30d以上(P<0.01);半相合基因移植实验组小鼠GVHD发生率为1/10,30d生存率增加至9/10(P<0.01),中位生存期延长至30d以上(P<0.01)。结论TJU103不仅可以显著抑制体外T淋巴细胞增殖效应,而且可显著降低小鼠同种异基因造血干细胞移植模型GVHD的发生率。     

异基因造血干细胞移植后慢性移植物抗宿主病小鼠模型的建立和评价

目的 采用化疗药物预处理方案建立异基因造血干细胞移植的慢性移植物抗宿主病小鼠模型,并进行评价.方法 以BALB/cH-2kd小鼠作为供鼠,C57BL/6H-2kd小鼠为受鼠.对受鼠使用不同的化疗药物进行预处理[方案1:白消安20mg/(kg·d)×4d+环磷酰胺150mg/(kg·d)×2 d;方案2:白消安20mg/(kg·d)×4 d+环磷酰胺100mg/(kg·d)×2 d],然后经尾静脉注射不同剂量的供鼠脾细胞(6×107或4×107个)和(或)相同剂量的骨髓细胞(2×107个),建立慢性移植物抗宿主病小鼠模型;采用嵌合体分析、临床评分、组织病理学等进行评价.结果 采用白消安20mg/(kg·d)×4d-+环磷酰胺150mg/(kg·d)×2d的方案进行预处理、2×107个骨髓单个核细胞+6×107个脾单个核细胞进行移植可形成较高水平的供受者混合嵌合体.移植物抗宿主病发生时间多集中在供鼠脾细胞输注后30～90 d,化疗药物剂量大的预处理方案及移植细胞数高的移植组小鼠的临床评分和慢性移植物抗宿主病的发生率高于化疗药物剂量小的预处理方案及移植细胞数少的移植组(P＜0.05).模型小鼠肠、肝脏、皮肤、脾脏等器官出现细胞和结构异常、炎症细胞浸润等病理改变.结论 采用白消安和环磷酰胺预处理、给予2×107个骨髓单个核细胞+6×107或4×107个脾单个核细胞可形成较稳定的慢性移植物抗宿主病小鼠模型,为进一步指导临床治疗慢性移植物抗宿主病奠定了实验基础.     

NK细胞对小鼠H-2单倍体相合骨髓移植后GVHD及造血重建的影响

目的:研究自然杀伤(NK)细胞在单倍体相合骨髓移植中对移植物抗宿主病(GVHD)及造血重建的影响. 方法: 以近交系Balb/c(H-2d)×C57BL/6(H-2b)杂交F1代小鼠(H-2d/b)为供鼠、Balb/c(H-2d)为受鼠,在移植物中增加供者的外周T细胞和(或)NK细胞进行半相合骨髓移植,根据临床表现、病理检查及外周血白细胞(WBC)数,比较不同移植组GVHD发生及造血重建情况. 结果: 骨髓 T细胞组中90%的小鼠出现GVHD,外周血WBC平均在移植后4 wk恢复正常;而骨髓 T 低浓度NK细胞组中20%小鼠出现GVHD, 外周血WBC平均在移植后3 wk恢复正常;骨髓 T 高浓度NK细胞组中仅10%出现GVHD,外周血WBC也平均在移植后3 wk恢复正常. 后两组较骨髓 T细胞组GVHD发生率显著下降(P＜0.01),外周血WBC恢复时间显著提前(P＜0.01). 结论:在小鼠单倍体相合骨髓移植中,同种反应性NK细胞可降低GVHD发生率,促进造血重建.     

不同成分淋巴细胞输注对荷瘤小鼠异基因骨髓移植的影响

目的:建立荷瘤小鼠非清髓异基因骨髓干细胞移植模型,探讨不同成分的供者淋巴细胞输注(DLI)对移植效果的影响及抗肿瘤机制. 方法: 受者鼠为Balb/c(H-2Kd)小鼠,供者鼠为C57bl/6(H-2Kb)小鼠,受者小鼠腹腔接种小鼠肝癌细胞株H22细胞,观察腹水生成情况及生存状况. 于接种瘤细胞后d5给予全身照射预处理,随后给受者小鼠尾静脉输注供者鼠的骨髓细胞,建立荷瘤小鼠的MHC不相合亚移植模型. 依据不同DLI将荷瘤鼠受者鼠随机分为A,B,C,D,E组,每组10只. A,B,C,D组均给予预处理,A组预处理后于移植d1,7给予供者小鼠全脾细胞0.5×107个;B组分别于移植d1,7给予去除CD8 细胞供者鼠脾细胞0.5×107个;C组于移植d1,7给予去除CD4 细胞供者鼠脾细胞0.5×107个;D 组只接受预处理不作移植及DLI;E组为对照组,既不作预处理,也不接受骨髓细胞移植及DLI. 观察各组成瘤率、生存期、嵌合状态、造血恢复情况及移植物抗宿主病(GVHD). 结果:所有小鼠均产生腹水,成瘤率100%;生存期C组最长为(35.6±3.1)d,B组为(23.7±10.9)d,B,C两组相比有统计学差异(P＜0.05);接受移植的A,B,C组嵌合率均高于0.80,只接受预处理的D组鼠白细胞计数自行恢复正常;GVHD评分C组与B组有明显差异(P＜0.05). 结论:建立非清髓荷瘤小鼠异基因骨髓干细胞移植模型条件适宜,说明去除CD4 细胞的DLI能够有效地减轻GVHD反应,延长荷瘤鼠生存期;去除CD8 细胞的DLI会加重GVHD反应,影响移植.     

大小鼠之间造血干细胞嵌合体抗异种移植物抗宿主病

目的探讨克服异种骨髓移植间强烈的移植物抗宿主病(GVHD)的措施。方法(1)将12只SD大鼠经5.0 Gy亚致死剂量全身照射后,4 h内每只经尾静脉输入28只正常BALB/c小鼠骨髓细胞8×107个。2 d后从腹腔注射环磷酰胺(Cy)100 mg/kg·b.w.,诱导形成对BALB/c小鼠产生特异性免疫耐受的嵌合体大鼠10只。(2)24只BALB/c小鼠接受9.0 Gy致死剂量全身照射后随机均分为3组,照射后4 h内经尾静脉注射骨髓细胞进行移植。A组输注正常SD大鼠的骨髓细胞4×107个;B组输注正常SD大鼠的骨髓细胞4×107个和脾细胞2×107个;C组输注嵌合体SD大鼠的骨髓细胞4×107个和脾细胞2×107个;观察GVHD的发生情况。结果A组有2只小鼠死于感染和放射损伤,所有对象均未观察到明显GVHD表现。B组平均累积存活时间为10 d[95%可信区间为(8,12)],死前均出现不同程度的典型GVHD表现。而C组除2只小鼠分别于移植后18、31 d死亡外,其余的均存活超过150 d。三组间比较有统计差异(P<0.002)。结论对有受者嵌合体的供者进行异种骨髓移植,有助于克服异种移植物抗宿主病。     

TK/GCV治疗H-2半相合CD34+和TK+T细胞移植急性移植物抗宿主病研究

目的探讨TK/GCV对H-2半相合CD34+细胞和TK+T细胞混合移植急性移植物抗宿主病(graft versus host disease GVHD)疗效,为临床应用提供实验依据.方法从亲代雄性供鼠骨髓分离CD34+细胞,同时取脾脏T细胞转染TK基因.两者混合移植雌性F1代受鼠,每只受鼠输入CD34+细胞和TK+T细胞分别为1×105和1×107.移植0天或移植7 d给予丙氧鸟苷(Ganciclovir,GCV)治疗,剂量为50mg/kg·d×7 d腹腔注射.结果F1受鼠全部发生急性GVHD,对照组小鼠3周内全部死亡;GCV治疗组与对照组相比差异显著,P＜0.01.移植0天或移植7 d应用GCV小鼠生存时间分别为(26.6±4.8)d和(40.5±8.4)d.移植7 d给予GCV疗效较好,P＜0.05.结论TK/GCV系统对H-2半相合CD34+和TK+T细胞混合移植急性GVHD有较好治疗作用;GCV给予时间不同疗效有差异.     

自然杀伤细胞对小鼠异基因骨髓移植中移植物抗宿主病效应的影响

目的:研究自然杀伤细胞(NK)在异基因骨髓移植中对移植物抗宿主病(GVHD)的影响.方法:以近交系小鼠C57BL/6(H-2b)为供鼠、BALB/c(H-2d)为受鼠,在移植物中增加供者的外周T细胞和(或)NK细胞进行异基因骨髓移植,根据临床表现和病理检查,比较不同移植组的存活率和GVHD发生情况.结果:增加1×106供鼠NK细胞的移植组中40%小鼠出现GVHD,增加2×106供鼠NK细胞的移植组中仅30%出现GVHD;与单纯异基因骨髓移植细(80%急性GVHD、20%慢性GVHD)和骨髓 T细胞组(100%急性GVHD)比较,GVHD发生率显著下降(P＜0.01),30、60和120 d存活率显著增高(P＜0.01).结论:在小鼠异基因骨髓移植中,同种异基因反应性NK细胞可抑制GVHD效应,延长存活期.     

小鼠慢性移植物抗宿主病荷瘤模型的建立

目的 通过供鼠淋巴细胞输注诱导小鼠慢性GVHD,并在此基础上荷瘤建立慢性GVHD的GVL模型,为研究慢性GVHD和GVL作用奠定基础.方法 以雄性BALB/c(H-2d)为供鼠,雌性CB6F1(BALB/c×C57BL/6 F1,H-2d/b)为受鼠,通过尾静脉输注8×107/个脾细胞诱导小鼠慢性移植物抗宿主病,在输注25天后,受鼠随机分组,通过尾静脉或腹腔或皮下方式接种P815肿瘤细胞,构建慢性GVHD荷瘤模型,用于研究慢性GVHD的同时研究GVT作用.结果 3种荷瘤方式均可形成荷瘤.尾静脉方式可形成小鼠白血病模型,符合人类疾病特点,成功构建慢性GVDH荷瘤的GVL模型.结论 成功建立小鼠慢性移植物抗宿主病荷瘤模型.     

移植前选择性去除同种异体反应供者淋巴细胞预防移植物抗宿主病的实验研究

目的探讨在移植前选择性去除同种异体反应的供者淋巴细胞预防移植物抗宿主病(GVHD)的效果。方法以(BALB/c×C57BL/6)F1雌性小鼠(H-2d/b)为受鼠,于第0天接受亚致死量的60Coγ射线全身照射(TB I),总剂量为4 Gy,第1天接种P388D1白血病细胞,第2天输注由C57BL/6雄性小鼠(H-2b)为供鼠提供的不相匹配的供者脾淋巴细胞,第6天再次TB I 9 Gy,第7天输注由(BALB/c×C57BL/6)F1雄性小鼠(H-2d/b)提供的骨髓造血干细胞。结果以TB I选择性去除同种异体反应供者淋巴细胞组的小鼠无白血病和GVHD的发生,生存期超过了210 d。对照组的小鼠出现了明显的GVHD、白血病或因出血、感染导致的死亡,生存期短,为20~36 d(P<0.01)。结论在造血干细胞移植前输注不相匹配的供者淋巴细胞诱导移植物抗白血病(GVL)效应,然后再选择性去除同种异体反应的供者淋巴细胞来预防GVHD的发生是可行的。     

非清髓性骨髓移植对移植物抗宿主病的影响

目的探讨非清髓性预处理方案对大鼠异基因骨髓移植模型移植物抗宿主病(GVHD)的影响.方法Wistar大鼠为供鼠,SD大鼠为受鼠,受鼠分两组,分别予以不同的预处理方案,A组受鼠自移植前4～1 d,腹腔注射氟达拉宾(1 mg/kg),移植前4 h接受2Gy的全身照射;B组受鼠仅在移植当天分别接受6 Gy的全身照射.各实验组受鼠均在移植当天经尾静脉输注供鼠骨髓细胞3.8×107;对照组大鼠输注等量的生理盐水,观察各组大鼠GVHD反应.结果移植前接受氟达拉宾和2 Gy全身照射预处理的大鼠生存期较长,且 GVHD 临床和病理评分也较低.结论非清髓性骨髓移植预处理方案可有效预防GVHD,拓宽临床进行异基因骨髓移植的适用范围.     

Effect of NK cells on GVHD in H-2 haploidentical bone marrow transplantation in mice

Objective To study the effect of natural killer (NK) cells on graft-versus-host disease (GVHD) after H-2 haploidentical bone marrow transplantation (BMT) in mice. Methods Murine model of H-2 haploidentical BMT was established by using Balb/c (H-2d) mouse as recipient, and Balb/c(H-2d)×C57BL/6 (H-2b) (H-2d/b) mouse as donor. Lethally irradiated Balb/c (H-2d) mice were transplanted with the bone marrow cells from Balb/c(H-2d)×C57BL/6(H-2b) (H-2d/b) mice containing donor spleen cells and/or NK cells. GVHD and survival rates were studied by observation of clinical manifestations and pathological changes. ResultsIn the group of bone marrow spleen cells, GVHD was induced in 90% mice; but in the group plus with low amount of NK cells,GVHD was induced in 20% mice; and in the group transplanted with high amount of NK cells, GVHD was induced only in 10% mice. Compared to the group transplanted only with BM plus spleen cells, the incidences of GVHD in the latter two groups decreased significantly (P＜0.01) and the survival rates at different periods of 15, 30, 45 and 60 days increased obviously (P＜0.01 ). Conclusion In mouse H-2 haploidentical BMT, alloreactive NK cells can reduce the incidence of GVHD and increase the survival rate.     

小鼠单倍体相合外周血移植模型的建立

目的建立单倍体相合外周血移植小鼠模型,探讨移植后造血及免疫重建特性。方法经大剂量全身照射预处理BDF1小鼠后,经尾静脉输注新生第一天DBA/2小鼠的外周全血,移植后动态观察受体鼠的造血重建及急性移植物抗宿主病(GVHD)发生情况,并用流式双染色法进一步检测粒系、淋巴系造血细胞的长期植入水平。结果移植后小鼠的白细胞、血小板、血红蛋白分别在第18、21、18天明显回升,其中白细胞和血小板分别于第29天和36天恢复正常,而血红蛋白至第50天仍为部分恢复。受体鼠90%长期存活,且不发生明显的GVHD。移植后第50天流式细胞仪检测供鼠来源的造血细胞占总有核细胞的88.81%,其中含供者来源的粒细胞33.92%,T细胞16.83%。结论单份新生小鼠外周血含有足够的造血干细胞,能重建单倍体相合小鼠的造血及免疫系统而不引起明显的GVHD,并可形成稳定的以供者细胞为主的嵌合体,其中粒细胞为完全嵌合。     

大小鼠之间造血干细胞嵌合体抗异种移植物抗宿主病

OBJECTIVE: To find a method for preventing graft-versus-host disease (GVHD) in BALB/c mice receiving rat bone marrow transplantation. METHODS: Firstly 12 SD rats were conditioned with 5.0 Gy sublethal total body irradiation(TBI), followed by infusion of 8 x 10(7) bone marrow cells from 28 BALB/c mice within 4 h and intraperitoneal administration of 100 mg/kg cyclophosphamide (Cy) 2 d later, for the purpose of inducing chimeric SD rats with specific immunological tolerance. Secondly, 24 BALB/c mice were exposed to 9.0 Gy lethal TBI and divided randomly into 3 equal groups designated respectively as groups A, B and C. Mice in group A were injected with 4 x 10(7) bone marrow cells from 4 normal rats, and mice in group B were injected with 4 x 10(7) bone marrow cells and 2 x 10(7) spleen cells from 4 normal rats, while those in group C were given 4 x 10(7) bone marrow cells and 2 x 10(7) spleen cells from 6 chimeric rats. The mice were then observed for 150 d for GVHD. RESULTS: In the second procedure, 2 mice in group A failed to survive due to infection and radiation injury respectively, and none of the rest mice presented signs of GVHD. The mice in group B all developed GVHD of varied degrees with symptoms as wasting, diarrhea, fur loss, arched body posture, and even bloody stool, and all died within 5 to 15 d with an average survival of 10.0 d (95% confidence interval 8,12). Pathological examination of the liver and intestinal tissues revealed inflammatory lymphocyte infiltration and necrosis. The majority of the mice in group C, in contrast, survived for more than 150 d with only two died on the postoperative days 18 and 31 respectively. The survival time of group B was significantly shorter than that of the other two groups. CONCLUSION: Donor/recipient chimerism may help prevent GVHD in xenogeneic bone marrow transplantation.     

人脐血源基质细胞对小鼠MHC半相合骨髓移植后GVHD的影响

目的探讨人脐血源基质细胞（hUCBDSC）对MHC半相合移植小鼠（移植物抗宿主反应）GVHD的影响及其可能机制。方法参照本室的方法从人脐血中分离培养hUCBDSC。建立小鼠MHC半相合骨髓移植GVHD模型,同时输注一定数量的hUCBDSC,观察小鼠的临床表现并进行GVHD评分,绘制Kaplan-Meier生存曲线,移植后14 d对小鼠皮肤、肝脏和小肠进行病理分析,流式细胞术分析小鼠脾脏中CD4＋Tregs的比例。结果和对照组相比,实验组的GVHD临床表现明显减轻。Kaplan-Meier生存曲线显示实验组的生存率明显高于对照组。移植后14d的病理切片HE染色结果显示实验组的病理程度显著低于对照组,脾脏CD4＋Tregs阳性率为10.5±0.7%,显著高于对照组6.6±0.5%。结论 hUCBDSC可能通过CD4＋Tregs减轻MHC半相合移植小鼠GVHD临床表现和病理变化,提高小鼠生存率。     

Graft-versus-leukemia effects from donor lymphocyte infusion after nonmyeloablative allogeneic bone marrow transplantation in mice

Background Nonmyeloablative allogeneic bone marrow transplantation has been used since the 1990s as a new hematological stem cell transplantation strategy for treating hematological diseases. The purpose of this study was to explore the graft-versus-leukemia (GVL) effects of donor lymphocyte infusions (DLIs) after nonmyeloablative allogeneic bone marrow transplantations, while assessing the declines in treatment-associated morbidity, mortality, and graft-versus-host disease (GVHD).Methods A total of 615 (H-2k) mice were injected with L615 tumor cells and received 500 cGy (60Coγ-ray) irradiation three days later, followed by an allogeneic bone marrow transplantation (allo-BMT). The allo-grafts consisted of 3×10（7） bone marrow cells and 1×10（7） spleen cells from BALB/C (H-2d) donor mice. Two days after the allo-BMT, the recipient mice were given 200 mg/kg of cyclophosphamide. Subsequently, recipient mice were infused with either donor spleen cells ［2×10（7）］ on day 14 or 21, or donor spleen cells ［5×10（7）］ pretreated with hydrocortisone and cyclosporin A (CsA) in vitro on day 14 post-BMT.Results The median survival time of mice that received DLI on day 21 and pretreated DLI on day 14 post-BMT was longer than that of controls and the day 14 DLI group (P&lt;0.01). No evidence of severe GVHD was observed in the day 21 DLI group nor in the day 14 treated DLI group. Mixed chimerism was confirmed in the day 14 DLI group, the day 14 treated DLI group, and the day 21 DLI group on the thirteenth day post-transplantation; full donor chimerism was observed two weeks after DLI.Conclusion Donor lymphocyte infusion after nonmyeloablative bone marrow transplantation may reduce transplantation-associated morbidity and mortality while strengthening graft-versus-leukemia effects.     

重组人白细胞介素18对小鼠骨髓细胞移植后急性移植物抗宿主病的影响

目的：探讨重组人白细胞介素18（rhIL-18）对小鼠异基因骨髓移植后急性移植物抗宿主病（aGVHD）的影响，为rhIL-18用于临床移植免疫提供理论基础。方法：受体鼠（BALB／c）接受9．0Gy剂量的X-射线照射之后，通过其尾静脉注射供体鼠（C57BL／6）的骨髓细胞和脾细胞，并于移植的-2～＋2d腹腔注射rhIL-18。移植后观察受体鼠的临床症状和存活状况，同时检测其肝脏、结肠和耳朵的病理变化。结果：移植后aGVHD期内，用rhIL-18治疗的受体鼠GVHD症状积分较未接受rhIL-18治疗的受体鼠低（P ＜ 0．05），肝脏和结肠的病理变化轻（P ＜ 0．05），短期存活时间延长（P ＜ 0．05），但对长期生存率无明显影响。结论：受体鼠早期接受rhIL-18治疗，可在移植后aGVHD期内降低aGVHD的病变程度，为rhIL-18在临床上预防和治疗aGVHD提供了实验依据。     

雷帕霉素联合未成熟树突状细胞诱导小鼠皮肤移植免疫耐受

目的 研究雷帕霉素联合供者骨髓来源的未成熟树突状细胞在诱导小鼠同种异基因皮肤移植免疫耐受中的协同作用.方法 健康雄性C57BL/6小鼠和BALB/C小鼠分别为供者、受者,建立同种异基因皮肤移植模型.对照组术前术后未给予任何免疫干预措施;雷帕霉素组术后第0天至第6天给予雷帕霉素灌胃;未成熟树突状细胞组将供者骨髓来源的未成熟树突状细胞于术前第7天经尾静脉输注给受者;联合组将供者骨髓来源的未成熟树突状细胞于术前第7d经尾静脉输注给受者,并在术后第0天至第6天给予雷帕霉素灌胃.结果 对照组、雷帕霉素组、未成熟树突状细胞组、联合组的皮肤移植物存活时间分别为(6.9±1.9)、(12.3±3.0)、(17.0±3.4)、(20.8±3.6)d.方差分析提示组间差异有显著性意义(P<0.05);SNK检验提示各组之间的差异均有显著意义.结论 雷帕霉素能延长小鼠皮肤移植物的存活时间;联合供者骨髓来源的未成熟树突状细胞可延长免疫耐受的持续时间.     

Transplantation tolerance mediated by regulatory T cells in mice

Background With potent suppressive effect on responder T cells, CD4+CD25+ regulatory T (Treg) cells have become the focus of attention only recently and they may play an important role in transplantation tolerance. However, the mechanism of action is not clear. This study was designed to assess the possibility of using CD4+CD25+ Treg cells to induce transplantation tolerance and to investigate their mechanism of action.Methods CD4+CD25+ Treg cells were isolated using magnetic cell separation techniques. Mixed lymphocyte reactions were used to assess the ability of Treg cells to suppress effector T cells. Before skin transplantation, various numbers of CD4+CD25+Treg cells, which have been induced using complex skin antigens from the donor, were injected into the host mice either intraperitoneally ［0.5×10(5), 1×10（5）, 2×10（5）, 3×10（5）, 4×10（5）, or 5×10（5）］ or by injection through the tail vein ［5×10（3）, 1×10（4）, 2×10（4）, 5×10（4）, 1×10（5）, 2×10（5）］. Skin grafts from two different donor types were used to assess whether the induced Treg cells were antigen-specific. The survival time of the allografts were observed. Single photon emission computed tomography was also used to determine the distribution of Treg cells before and after transplantation. Results Treg cells have suppressive effect on mixed lymphocyte reactions. Grafts survived longer in mice receiving CD4+CD25+ Treg cell injections than in control mice. There was a significant difference between groups receiving intraperitoneal injection of either 2×10（5） or 3×10（5） CD4+CD25+Treg cells and the control group (P&lt;0.05, respectively). Better results were achieved when Treg cells were injected via the tail vein than when injected intraperitoneally. The transplantation tolerance induced by CD4+CD25+ Treg cells was donor-specific. Analysis of the localization of Treg cells revealed that Treg cells mainly migrated from the liver to the allografts and the spleen.Conclusions CD4+CD25+Treg cells can induce donor-specific transplantation tolerance. Cell-to-cell contact may be the primary mechanism by which Treg cells act on effector T cells.     

人脐血CD34~+细胞在NOD/SCID小鼠体内重建体液免疫的实验研究

目的探讨人脐血CD34+造血干细胞(HSC)在NOD/SCID小鼠模型体内体液免疫功能重建的作用。方法从新鲜脐血中分离出单个核细胞(MNC),利用免疫磁珠分选法筛选CD34+造血干细胞,经尾静脉输注入经亚致死剂量照射的NOD/SCID小鼠体内,移植后4、6、8、10周分批处死存活的小鼠,取其脾脏和外周血,分别进行细胞表型分析、体液免疫分析,监测小鼠体液免疫功能重建情况。结果照射2周后,阴性对照组小鼠全部死亡,6周后移植组小鼠存活率为37.5%,空白对照组小鼠存活率为100%。移植4、6、8、10周移植组外周血人CD45+细胞表达(%)分别为4.87±1.23、9.22±2.07、12.34±2.38、8.14±2.36,CD19+B淋巴细胞表达(%)分别为1.07±0.50、2.17±0.95、3.34±0.90、1.67±0.90。移植后10周,在移植组小鼠脾脏可见CD19+B淋巴细胞分布。结论经照射后的NOD/SCID小鼠通过人脐血CD34+细胞植入可建立起人鼠嵌合免疫模型。缺少相应细胞因子刺激,CD34+细胞分化能力随时间减弱。