CD8+CD44(hi) but not CD4+CD44(hi) memory T cells mediate potent graft antilymphoma activity without GVHD

Allogeneic hematopoietic cell transplantation can be curative in patients with leukemia and lymphoma. However, progressive growth of malignant cells, relapse after transplantation, and graft-versus-host disease (GVHD) remain important problems. The goal of the current murine study was to select a freshly isolated donor T-cell subset for infusion that separates antilymphoma activity from GVHD, and to determine whether the selected subset could effectively prevent or treat progressive growth of a naturally occurring B-cell lymphoma (BCL(1)) without GVHD after recipients were given T cell-depleted bone marrow transplantations from major histocompatibility complex-mismatched donors. Lethal GVHD was observed when total T cells, naive CD4(+) T cells, or naive CD8(+) T cells were used. Memory CD4(+)CD44(hi) and CD8(+)CD44(hi) T cells containing both central and effector memory cells did not induce lethal GVHD, but only memory CD8(+) T cells had potent antilymphoma activity and promoted complete chimerism. Infusion of CD8(+) memory T cells after transplantation was able to eradicate the BCL(1) lymphoma even after progressive growth without inducing severe GVHD. In conclusion, the memory CD8(+) T-cell subset separated graft antilymphoma activity from GVHD more effectively than naive T cells, memory CD4(+) T cells, or memory total T cells.     

TNF downmodulates the function of human CD4+CD25hi T-regulatory cells

CD4+CD25+ T-regulatory cells (Tregs) play an essential role in maintaining immunologic homeostasis and preventing autoimmunity. However, little is known about the exogenous factors that regulate their differentiation and function. Here, we report that TNF inhibits the suppressive function of both naturally occurring CD4+CD25+ Tregs and TGFbeta1-induced CD4+CD25+ T-regulatory cells. The mechanism of this inhibition involves signaling through TNFRII that is constitutively expressed selectively on unstimulated Tregs and that is up-regulated by TNF. TNF-mediated inhibition of suppressive function is related to a decrease in FoxP3 mRNA and protein expression by the Tregs. Notably, CD4+CD25hi Tregs isolated from patients with active rheumatoid arthritis (RA) expressed reduced levels of FoxP3 mRNA and protein and poorly suppressed the proliferation and cytokine secretion of CD4+ effector T cells in vitro. Treatment with anti-TNF antibody (infliximab) increased FOXP3 mRNA and protein expression by CD4+CD25hi Tregs and restored their suppressive function. Thus, TNF has a novel action in modulating autoimmunity, by inhibiting CD4+CD25+ Treg activity.     

CD4+CD25+调节性T细胞及其与移植物抗宿主病和移植物抗白血病的关系

CD4 CD25 调节性T细胞(Treg细胞)是CD4 T细胞的一个亚群,在维持机体自身免疫耐受,诱导移植耐受等方面发挥重要作用。移植物抗宿主病(GVHD)是异基因造血干细胞移植最严重的并发症之一。在动物骨髓移植模型中证实Treg细胞可以促进移植物植入,减少GVHD的发生率和严重度,但并没有消除移植物抗白血病(GVL)的作用。在人体有关Treg细胞对GVHD的影响因研究者分析Treg细胞采用的表型不同,其结论存在不一致性。本文就新近Treg细胞生物学特性,Treg细胞与GVHD和GVL的关系的研究进展进行综述。     

供体CD+4CD+25T细胞及调控基因FOXP3在急性移植物抗宿主病中的作用

目的 探讨供体CD+4CD+25T细胞亚群、FOXP3调控基因的表达与受者移植物抗宿主病(GVHD)的相关性.方法 (1)30例异基因造血干细胞移植(allo-HSCT),采用免疫荧光标记和流式细胞术检测并比较供体粒细胞集落刺激因子(G-CSF)动员前外周血、动员后采集物CD+4CD+25T细胞亚群比例,随访异基因移植后GVHD的发生率和严重程度.(2)应用RT-PCR技术检测供体FOXP3基因表达情况,分析其与GVHD、疾病复发的相关性.结果 (1)所有患者均获造血重建,粒细胞绝对数(ANC)≥0.5×109/L的中位时间为14(12～15)d,PLT≥20×109/L为18(15～25)d.30例allo-HSCT,中位随访时间12.8(8～16)个月,Ⅰ～Ⅳ度急性GVHD分别为3、4、3、5例.慢性GVHD 6例.(2)供体G-CSF动员前外周血、动员后采集物CD+4CD+25T细胞亚群分别为(2.67±0.38)%、(5.01±1.33)%,两者相比差异无统计学意义(P＞0.05).(3)移植后无急性GVHD组、Ⅰ～Ⅱ度急性GVHD组、Ⅲ～Ⅳ度急性GVHD组供体CD+4CD+25T细胞亚群分别为(5.05±1.34)%、(4.17±1.73)%、(1.98±1.10)%.其中Ⅰ～Ⅱ度急性GVHD组与Ⅲ～Ⅳ度急性GVHD组相比差异有统计学意义(P=0.04),无急性GVHD组与Ⅲ～Ⅳ度急性GVHD组相比差异有统计学意义(P=0.002).(4)30例allo-HSCT,7例FOXP3基因表达阳性,5/7例移植后无急性GVHD,其中3例移植后复发,另2/7例移植后Ⅰ度急性GVHD,Ⅱ～Ⅳ度急性GVHD患者FOXP3均不表达.结论 (1)供体CD+4CD+25T细胞亚群比例与受者急性GVHD的发生具有一定的相关性,提高供体CD+4CD+25T细胞数量有望减低移植后急性GVHD发生率.(2)供体移植物FOXP3基因表达阳性,与移植后有无严重急性GVHD发生存在一定相关性.     

Only the CD62L+ subpopulation of CD4+CD25+ regulatory T cells protects from lethal acute GVHD

CD4+CD25+ regulatory T (Treg) cells are potent modulators of alloimmune responses. In murine models of allogeneic bone marrow transplantation, adoptive transfer of donor CD4+CD25+ Treg cells protects recipient mice from lethal acute graft-versus-host disease (aGVHD) induced by donor CD4+CD25- T cells. Here we examined the differential effect of CD62L+ and CD62L- subsets of CD4+CD25+ Treg cells on aGVHD-related mortality. Both subpopulations showed the characteristic features of CD4+CD25+ Treg cells in vitro and did not induce aGVHD in vivo. However, in cotransfer with donor CD4+CD25- T cells, only the CD62L+ subset of CD4+CD25+ Treg cells prevented severe tissue damage to the colon and protected recipients from lethal aGVHD. Early after transplantation, a higher number of donor-type Treg cells accumulated in host mesenteric lymph node (LN) and spleen when CD4+CD25+CD62L+ Treg cells were transferred compared with the CD62L- subset. Subsequently, CD4+CD25+CD62L+ Treg cells showed a significantly higher capacity than their CD62L- counterpart to inhibit the expansion of donor CD4+CD25- T cells. The ability of Treg cells to efficiently enter the priming sites of pathogenic allo-reactive T cells appears to be a prerequisite for their protective function in aGVHD.     

Role for CTLA-4 but not CD25+ T cells during Schistosoma mansoni infection of mice

Schistosoma mansoni infection of mice increases the frequency of cells that are CD4+ CD25+ in the acute (4 and 8 weeks) and chronic (16 week) stages of infection. Depletion of > 85% of CD25+ cells in the acute or chronic stages of schistosome infection caused no overt changes in morbidity or immunological responses. The absence of effect in mice with CD25+ cells depleted may be due to the preferential expression of IL-4 and IL-10, two cytokines that are protective in schistosome infection, on CD25- CD4+ cells. We also assessed infection-induced changes of other regulatory markers, GITR, CD103 and CTLA-4 on CD4+ cells. We identified a marked expansion of CTLA-4+ population on CD25- CD4+ cells in acute and chronic infection. Blocking of CTLA-4 during acute, but not chronic infection, caused significant weight loss and altered the type 2 cytokine response of mice, with increased IL-4 and IL-5 production associated with significantly more Th2 cells and eosinophils in the liver granuloma. This study illustrates the complexity of regulation of T cells in schistosome infection and highlights a specific role for CTLA-4+, but not CD25+ cells, in the regulation of Th2 responses in helminth infection.     

支气管哮喘大鼠CD4+CD25+T细胞的变化及地塞米松干预作用的研究

目的 研究支气管哮喘(简称哮喘)大鼠模型支气管肺泡灌洗液(BALF)、血液、脾脏CD4+CD25+T细胞的变化,及地塞米松对CD4+CD25+T细胞的影响.方法 50只SD大鼠随机分为5组,空白对照(A)组,哮喘(B)组,地塞米松1(C)组、地塞米松2(D)组,地塞米松3(E)组.A组第l天给予腹腔注射生理盐水l ml,第15～21天每天给予生理盐水雾化.B、C、D、E组用卵蛋白建立哮喘大鼠模型,第1天,每只大鼠腹腔注射抗原l ml(卵蛋白1 mg+灭活百日咳杆菌9×106个+氢氧化铝干粉100 mg)混悬液,第15～21天给予1%的卵蛋白雾化30 min,C、D、E组于雾化后分别给予腹腔注射地塞米松0.2 mg/kg、1 mg/kg、2 mg/kg.采用流式细胞仪检测的方法 ,观察大鼠体内BALF、外周血、脾脏CD4+CD25+T细胞的变化及使用不同剂量地塞米松后对其的影响.结果 B组BALF、外周血、脾脏CD4+CD25+T细胞表达占CD4+T细胞的百分比分别是(42.21±5.62)%、(12.69±2.70)%、(11.15±1.05)%,A组结果 分别是(18.76±5.85)%、(6.21±1.73)%、(7.85±2.13)%.B组与A组比较,差异均具有统计学意义(P＜0.01,P＜0.01,P＜0.05);C组、D组、E组BALF中CD4+CD25+T细胞占CD4+T细胞的百分比表达分别是(10.49±4.03)%、(13.28±5.12)%、(7.51±5.39)%,显著低于A组和B组,(P＜0.05,P＜0.01);外周血中,C组(6.03±1.43)%、D组(4.88±0.95)%与A组(6.21±1.73)%比较,差异无统计学意义,E组(3.49±0.62)%与C组、A组比较,差异有统计学意义(P＜0.05).脾脏中,C组(7.25±1.82)%、D组(8.63±3.18)%与A组(7.85±2.13)%比较,差异无统计学意义,E组(3.38±1.37)%与C组、D组、A组比较,差异有统计学意义(P＜0.05).结论 CD4+CD25+T细胞在哮喘大鼠体内有明显的优势表达,可能是哮喘发病的机制之一.地塞米松可以抑制CD4+CD25+T细胞的表达.BALF内CD4+CD25+T细胞的变化与外周血和脾脏的变化具有一致性,监测外周血或脾脏CD4+CD25+T细胞变化可了解肺部情况.     

支气管哮喘大鼠CD4^＋CD25^＋T细胞的变化及地塞米松干预作用的研究

目的研究支气管哮喘（简称哮喘）大鼠模型支气管肺泡灌洗液（BALF）、血液、脾脏CD4^＋CD25^＋T细胞的变化,及地塞米松对CD4^＋CD25^＋T细胞的影响。方法50只SD大鼠随机分为5组,空白对照（A）组,哮喘（B）组,地塞米松1（C）组、地塞米松2（D）组,地塞米松3（E）组。A组第1天给予腹腔注射生理盐水1ml,第15～21天每天给予生理盐水雾化。B、C、D、E组用卵蛋白建立哮喘大鼠模型,第1天,每只大鼠腹腔注射抗原1ml（卵蛋白1mg＋灭活百日咳杆菌9×10。个＋氢氧化铝干粉100mg）混悬液,第15～21天给予1％的卵蛋白雾化30min,C、D、E组于雾化后分别给予腹腔注射地塞米松0．2mg／kg、1mg／kg、2mg／kg。采用流式细胞仪检测的方法,观察大鼠体内BALF、外周血、脾脏CD4^＋CD25^＋T细胞的变化及使用不同剂量地塞米松后对其的影响。结果B组BALF、外周血、脾脏CD4^＋CD25^＋T细胞表达占CD4^＋T细胞的百分比分别是（42．21±5．62）％、（12．69±2．70）％、（11．15±1．05）％,A组结果分别是（18．76±5．85）％、（6．21±1．73）％、（7．85±2．13）％。B组与A组比较,差异均具有统计学意义（P〈0．01,P〈0．01,P〈0．05）;C组、D组、E组BALF中CD4^＋CD25^＋T细胞占CD4^＋T细胞的百分比表达分别是（10．49±4．03）oA、（13．28±5．12）％、（7．51±5．39）％,显著低于A组和B组,（P〈0．05,P〈0．01）;外周血中,C组（6．03±1．43）％、D组（4．88±0．95）％与A组（6．21±1．73）％比较,差异无统计学意义,E组（3．49士0．62）％与C组、A组比较,差异有统计学意义（P〈0．05）。脾脏中,c组（7．25±1．82）%、D组（8．63±3．18）％与A组（7．85±2．13）％比较,差异无统计学意义,E组（3．38±1．37）％与C组、D组、A组比较,差异有统计学意义（P〈0．05）。结论CD4^＋CD25^＋T细胞在哮喘大鼠体内有明显的优势表达,可能是哮喘发病的机制之一。地塞米松可以抑制CD4^＋CD25^＋T细胞的表达。BALF内CD4^＋CD25^＋T细胞的变化与外周血和脾脏的变化具有一致性,监测外周血或脾脏CD4^＋CD25^＋T细胞变化可了解肺部情况。     

Suppression of natural killer cell-mediated bone marrow cell rejection by CD4+CD25+ regulatory T cells

Naturally occurring CD4(+)CD25(+) T regulatory (Treg) cells have been shown to inhibit adaptive responses by T cells. Natural killer (NK) cells represent an important component of innate immunity in both cancer and infectious disease states. We investigated whether CD4(+)CD25(+) Treg cells could affect NK cell function in vivo by using allogeneic (full H2-disparate) bone marrow (BM) transplantation and the model of hybrid resistance, in which parental marrow grafts are rejected solely by the NK cells of irradiated (BALB/c x C57BL/6) F(1) recipients. We demonstrate that the prior removal of host Treg cells, but not CD8(+) T cells, significantly enhanced NK cell-mediated BM rejection in both models. The inhibitory role of Treg cells on NK cells was confirmed in vivo with adoptive transfer studies in which transferred CD4(+)CD25(+) cells could abrogate NK cell-mediated hybrid resistance. Anti-TGF-beta mAb treatment also increased NK cell-mediated BM graft rejection, suggesting that the NK cell suppression is exerted through TGF-beta. Thus, CD4(+)CD25(+) Treg cells can potently inhibit NK cell function in vivo, and their depletion may have therapeutic ramifications for NK cell function in BM transplantation and cancer therapy.     

CD8+ but not CD4+ T cells require cognate interactions with target tissues to mediate GVHD across only minor H antigens, whereas both CD4+ and CD8+ T cells require direct leukemic contact to mediate GVL

Whether T-cell antigen receptors (TCR) on donor T cells require direct interactions with major histocompatibility complex class I or class II (MHCI/MHCII) molecules on target cells to mediate graft-versus-host disease (GVHD) and graft-versus-leukemia (GVL) is a fundamental question in allogeneic stem-cell transplantation (alloSCT). In MHC-mismatched mouse models, these contacts were not required for GVHD. However, this conclusion may not apply to MHC-matched, multiple minor histocompatibility antigen-mismatched alloSCT, the most common type performed clinically. To address this, we used wild-type (wt)-->MHCI-/- or wt-->MHCII-/- bone marrow chimeras as recipients in GVHD experiments. For GVL experiments, we used MHCI-/- or MHCII-/- chronic-phase CML cells created by expressing the BCR-ABL cDNA in bone marrow from MHCI-/- or MHCII-/- mice. TCR/MHCI contact was obligatory for both CD8-mediated GVHD and GVL. In contrast, CD4 cells induced GVHD in wt-->MHCII-/- chimeras, whereas MHCII-/- mCP-CML was GVL-resistant. Donor CD4 cells infiltrated affected skin and bowel in wt-->MHCII-/- recipients, indicating that they mediated GVHD by acting locally. Thus, CD4 cells use distinct effector mechanisms in GVHD and GVL: direct cytolytic action is required for GVL but not for GVHD. If these noncytolytic pathways can be inhibited, then GVHD might be ameliorated while preserving GVL.     

The immune response to lentiviral-delivered transgene is modulated in vivo by transgene-expressing antigen-presenting cells but not by CD4+CD25+ regulatory T cells

Systemic delivery of lentiviral vector (LV) in immunocompetent mice leads to efficient in vivo cell transduction and expression of the encoded protein under the control of the ubiquitous promoter of human cytomegalovirus (CMV). However, antitransgene immune response results in clearance of transduced cells 4 weeks after injection. T regulatory cells (Tregs), which have been demonstrated to control immune responses in vivo, were tested for their ability to suppress antitransgene response leading to stable long-term expression. Adoptive transfer of natural CD4(+)CD25(+) Tregs (nTregs) isolated from wild type (wt) mice or from transgene tolerant transgenic (tg) mice did not suppress the antitransgene immune response after LV delivery. These data demonstrate that neither increasing the endogenous pool of natural Tregs nor transferring nTregs selected in a transgene-expressing thymus can modulate the immune response and mediate sustained transgene expression. Conversely, adoptive transfer of antigen-presenting cells (APCs) isolated from transgene-tolerant tg mice efficiently reduced the immune response leading to stable LV-encoded protein expression in vivo. Reduction of CD8(+) effector T cells was observed in LV-treated mice coinjected with transgene-expressing APCs compared with control mice. These data indicate that antitransgene immune response can be modulated by transgene-expressing APCs possibly through deletion of effector T cells.