Regulatory CD4+ T cells in allergic asthma

Active suppression by regulatory T cells (T_regs) appears to play a key role in the downregulation of T-cell responses to foreign antigens. Several subtypes of T_regs have been described but their mechanisms of action remain unclear. Recent data demonstrate that the suppressive capacity of natural T_regs could be associated with cytotoxicity due to the release of granzymes, which are capable of apoptosis induction in target effector T lymphocytes and in antigen-presenting cells, such as dendritic cells. The mechanism of such nonspecific T_regs is discussed. Peptide immunotherapy is thought to induce regulatory cells capable of suppressing autoimmune and allergic diseases. We have recently optimized a vaccination strategy by which cytotoxic antigen-specific adaptive T_regs can be elicited towards allergens involved in allergic asthma. Such a strategy could be of value in the treatment of allergic asthma.     

D4+调节性T细胞的异质性和可塑性

CD4+调节性T细胞(Treg)是一群具备外周免疫抑制功能的辅助性T淋巴细胞,在维持机体内环境稳定、预防自身免疫病、控制移植排斥、肿瘤免疫逃逸、慢性炎症和持续感染等生理病理过程中发挥重要作用.CD4+Treg是一个异质性的群体,各亚群的分化、表型、功能均有所不同.近年研究尚且发现其存在可塑性(plasticity).作...     

The Role of CD4+CD25+ T Regulatory Cells in Autoimmune Diseases

Among the several mechanisms that play role in maintaining peripheral self-tolerance is the existence of a unique CD4+CD25+ population of naturally occurring regulatory T (Treg) cells that actively prevent both the activation and the effector function of autoreactive T cells that have escaped different mechanisms of tolerance. Many studies have shown the benefit of targeting this cell population by restoring self-tolerance. Therapies that could possibly increase the suppressive ability of T regulatory cells were proven to improve that course of autoimmune diseases.     

CD4+CD25+调节性T细胞在自身免疫病中作用的研究进展

CD4 CD25 调节性T细胞具有独特的免疫抑制功能,通过细胞接触和细胞因子机制抑制自身反应性T细胞的活化与增殖,在自身免疫病中发挥着重要作用。通过研究CD4 CD25 调节性T细胞在自身免疫病中的作用,将会揭示这类疾病的发病机制,从而为治疗自身免疫病提供一个新途径。     

Biological and Environmental Correlates of Developmental Outcome of Prematurely Born Infants in Early Adolescence

Examined the role of biological factors (birth weight and perinatalmedical complications) and psychosocial factors (maternal attitudes,paternal involvement, mother's personal state, marital adjustment,family relations, and socio-economic status) in predicting long-termoutcome of 90 Israeli adolescents born prematurely at very lowbirth weight (VLBW). As compared with 90 adolescents born full-termat normal birth weight (NBW), the VLBW children scored loweron all measures except reading comprehension. IQ, visual-motorcoordination, and hyperactive behavior were predicted by bothbiological and psychosocial variables, visual memory by biologicalvariables, and reading comprehension by psychosocial variables.The findings support chiefly the main effects model of developmentalpsychopathology (i.e., biological and psychosocial variablesare additive in predicting outcomes), but also the interactionalmodel (e.g., SES was influential in predicting visual-motorcoordination and hyperactive behavior in the VLBW group butnot in the NBW group)     

CD4+CD25+调节性T细胞对B细胞免疫应答的抑制作用

CD4 CD25 调节性T细胞(CD4 CD25 Treg细胞)主要来源于胸腺,在体内外抑制CD4 或CD8 T细胞的活化及增殖,是维持自身免疫耐受的重要机制之一。近来研究发现该调节性T细胞除了能够抑制T细胞的免疫应答外,还能够抑制B细胞免疫应答,包括抑制B细胞活化和抗体生成,从而抑制主要由抗体介导的自身免疫性疾病的发生。     

Neonatal Autoimmune Disease: Influence of CD4+ CD25+ Regulatory T Cells

Although previous studies have emphasized the tolerogenic property of murine neonatal immune system, recent studies indicate that neonatal mice are prone to autoimmune disease. This chapter will summarize the evidence for neonatal propensity to autoimmune ovarian disease (AOD) and describe the new finding that autoantibody can trigger a T cell–dependent autoimmune disease in neonatal but not adult mice. Based on depletion or addition of the CD4⁺CD25⁺ T cells, disease resistance of older mice is explicable by the emergence of CD4⁺CD25⁺ regulatory T-cell function after day 5, whereas disease susceptibility is associated with resistance to regulation by CD4⁺CD25⁺ T cells.     

Regulatory CD4+ CD25+ T cells prevent thymic dysfunction in experimental chronic colitis

Chronic colitis in T-cell deficient Tg epsilon26 mice develops due to a dysfunction of the thymus which generates colitogenic T cells after bone marrow (BM) transplantation. Regulatory CD4+ CD25+ T cells have been shown to prevent colitis in this model by normalizing the peripheral T-cell pool. We tested the hypothesis that T-cell normalization takes place in the thymus. Tg epsilon26 mice were transplanted with BM (BM-->Tg epsilon26 mice) and consequently received either CD4+ CD25+ or CD4+ CD25- cells from syngenic wild type mice. Furthermore, untransplanted Tg epsilon26 mice received CD4+ CD25+ or CD4+ CD25- cells or complete mesenteric lymph node cells. Transfer of regulatory. CD4+ CD25+ cells normalized the total number of thymocytes and the percentage and number of double positive CD4+ CD8+ cells in transplanted mice while percentage of single positive CD4+ and CD8+ thymocytes in BM-->Tg epsilon26 mice was reduced upon CD4+ CD25+ transfer. Timing of CD4+ CD25+ cell injection was important as transfer later than 7 days after BM transplantation failed to prevent abnormal thymic T-cell distribution in BM-->Tg epsilon26 mice. Isolated CD4+ CD25+ cell transfer without preceding BM transplantation failed to reconstitute thymic architecture. Differences of thymic cell composition could not be exclusively explained by presence or absence of colitis, respectively, because 19 days after BM transplantation when both groups showed no histological signs of colitis, animals transferred with CD4+ CD25+ T cells had a significantly higher percentage and number of CD4+ CD25+ thymocytes and CD4+ Foxp3+ cells than BM-->Tg epsilon26 mice. In conclusion, early CD4+ CD25+ cotransfer prevents thymic dysfunction which underlies immune-mediated bowel inflammation in BM-->Tg epsilon26 mice.     

A Novel Splice Variant of FR4 Predominantly Expressed in CD4+CD25+ Regulatory T Cells#

Folate receptor 4 (FR4) is recently found as a lymphoid tissue specific protein. In this study, we have identified an alternative splicing variant of the FR4 gene from murine splenocytes, termed FR4v, which is almost identical to FR4 cDNA sequence except with the retained 108 bp intron 3 between exon 3 and 4 of FR4 gene. FR4v mRNA encodes a larger protein than FR4 and is constitutively expressed on CD4⁺CD25⁺ regulatory T cell (Treg) membrane via a GPI anchor mechanism. Whether FR4v plays a redundant or unique functional role in Tregs should be investigated further in the future.     

Regulatory CD4+ T cells and the control of autoimmune disease

The immune system is a delicately balanced network of interacting cells. In recent years, the concept of immune regulation/suppression has been firmly established, and both natural and induced regulatory cells play vital roles in protection from autoimmune disease. Recent work has revealed the diverse nature of regulatory CD4+ T (Treg) cells and the molecules involved in their function. Innate and adaptive responses to infection are able to override the suppressive properties of such regulatory cells, whereas several reports point to deficiencies in regulatory cell function in autoimmune disease. Protocols have been developed that allow the expansion of Treg cells in vitro and their antigen-specific induction in vivo. A full understanding of Treg differentiation and function will facilitate the development of improved strategies for prevention and treatment of autoimmune diseases.     

A Role for Trichosanthin in the Expansion of CD4+CD25+ Regulatory T Cells

CD4⁺CD25⁺ regulatory T cells (Tregs) are critical for the peripheral immune tolerance. Understanding the signals for the generation of Tregs is important for the clinical immunotherapy, but only limited progress has been made on obtaining enough peripheral Tregs. The aim of this study was to evaluate the role of trichosanthin (Tk) extracted from Chinese medicinal herb Trichosanthes kirilowi on the function of Tregs in vitro and in vivo. We reported here that Tk is needed for the expansion of freshly isolated CD4⁺CD25⁺Tregs (nTregs) into Tk‐expanded CD4⁺CD25⁺Tregs (Tk‐Tregs) through up‐regulating CD25 and Foxp3 expression. The dose–response analyses indicated that 100 ng/ml Tk was the most appropriate dose. The result of real‐time PCR showed that Tk‐Tregs expressed 1.5‐fold higher levels of Foxp3 than those observed in nTregs. Tk ‐ Tregs markedly suppressed activation of effector T cells at a suppressor/responder ratio of 1:1, 1:2, 1:4, 1:8 or 1:16, and their effect was dose dependent. Moreover, Tk‐Tregs secreted more immunosuppressive cytokines interleukin (IL)‐10 and transforming growth factor (TGF)‐β1 after stimulating with antigen and antigen‐presenting cells (APC). Transwell experiments showed that not only cell‐to‐cell contact but also soluble cytokines were involved in suppressive mechanism of Tk‐Tregs. And Tk‐Tregs were more efficient in suppressing CD25^?T cell response to specific antigen than to irrelative antigen. Most importantly, it was revealed for the first time that Tk‐Tregs could prolong the survival duration of mice with acute graft‐versus‐host disease (aGVHD). In conclusion, the study suggests a possible therapeutic potential of Tk‐Tregs for clinical treatment on aGVHD.     

Regulatory CD4+CD25+ T cells and macrophages: communication between two regulators of effector T cells

Regulatory T cells (Tregs) play an essential role in the induction and maintenance of peripheral tolerance as well as prevention of autoimmunity by limiting the strength of the immune response of effector T cells. Macrophages, a heterogeneous population of phagocytes and professional antigen presenting cells (APCs), can also exert suppressive effects on effector T cells to keep the peripheral balance of immunity. The bi-directional interactions of dendritic cells (DCs) and Tregs have been cell studied. However, much less is known about the reciprocal interaction between macrophages and Tregs. In this review, we will discuss recent observations regarding the interplay of these two regulators of immunity. Received 8 December 2006; returned for revision 17 January 2008; received from final revision 9 June 2008; accepted by G. Wallace 10 July 2008     

Regulatory CD4+CD25+ T lymphocytes in peripheral blood from patients with atopic asthma

The aim of this study was to analyze whether regulatory CD4+CD25+ T lymphocytes exist and function normally in patients with atopic asthma. Our data showed that a significant increase in CD4+CD25+ cell numbers was seen in atopic asthmatics during acute exacerbation, but not in those stable asthmatics, atopic nonasthmatics, and normal subjects. The mean inhibition values of the proliferation response of CD4+CD25- cells by CD4+CD25+ cells from normal controls and asthmatics were almost the same. There was no difference in inhibitory effects on both Th1 and Th2 cytokine production of CD4+CD25- cells by CD4+CD25+ cells in the two groups. These data demonstrated that although CD4+CD25+ cells increase in atopic asthma during exacerbation, these regulatory T cells appear to function normally with regard to suppression of T-cell proliferation as well as Th1-Th2 cytokine production.     

CD4+CD25+调节性T细胞及血小板参数在重症肺炎患者中表达的意义

目的 探讨CD4+ CD25+调节性T细胞及血小板参数在重症肺炎患者中表达的意义.方法 收集2013年5月至2015年10月我院诊断为肺炎的患者,共计80例,进一步分为重症肺炎组28例和肺炎组52例.对照组为同期健康体检者,共50例.对比重症肺炎组、肺炎组和对照组入院时CD4+ CD25+调节性T细胞及血小板参数水平,并且分析重症肺炎组死亡患者与存活患者入院时CD4+ CD25+调节性T细胞及血小板参数水平.结果 ①重症肺炎组、肺炎组和对照组入院时CD4+ CD25+调节性T细胞水平、MPV及PLT结果比较有差异(P＜0.05);重症肺炎组、肺炎组和对照组入院时PDW、PCT结果比较无差异(P＞0.05).②重症肺炎组死亡患者与存活患者入院时CD4+ CD25+调节性T细胞水平、MPV及PLT结果比较有差异(P＜0.05);重症肺炎组死亡患者与存活患者入院时PDW、PCT结果比较无差异(P＞0.05).结论 CD4+ CD25+调节性T细胞、MPV及PLT可作为反应肺炎严重程度的敏感指标,并且可作为评价重症肺炎患者预后的客观指标.     

Regulatory circuits in autoimmunity: recruitment of counter-regulatory CD8+ T cells by encephalitogenic CD4+ T line cells

In this study, pretreatment of Lewis rats with a syngeneic encephalitogenic T cell line (S1) was found to be able to constantly induce resistance to the subsequent induction of transferred experimental autoimmune encephalomyelitis (tEAE). This treatment was capable of protecting recipient animals for at least 2-4 months. Here we show an enhanced suppressor T(anti-S1) cell activity, which can be readily detected in the lymphoid organs of animals which recovered from S1-induced tEAE, or from rats pretreated with attenuated (irradiated, fixative treated or water-lysed) S1 cells. Anti-S1 cells, which uniformly express the CD8 phenotype, were selectively stimulated to grow and expand into lines by confronting primed lymphoid cells with irradiated S1 cells in culture. The proliferative response of anti-S1 cells was independent of myelin basic protein and antigen-presenting cells, and the responses against unrelated encephalitogenic T cell lines were minimal. It was also found that none of the monoclonal antibodies tested (including CD8 and MHC class I antigen-specific antibodies) was able to block S1/anti-S1 interactions. These cells are functionally suppressive to the proliferation of S1 cells in vitro, are specifically cytolytic directed against the EAE-inducing S1 cells and are able to antagonize encephalitogenic capacity of S1 cells in vivo. In vivo elimination of the CD8+ T subset from Lewis rats, using a combined treatment of thymectomy and OX-8 antibody injection before the initial cell transfer, totally blocked the induction of resistance. Our experiments document that induction of functionally active suppressor T cells is responsible for the induced resistance observed in tEAE.     

重症肌无力患者外周血CD5~+B细胞和CD4~-CD8~-T细胞的变化

研究重症肌无力 (MG )患者外周血CD5 + B细胞和CD4 CD8 T细胞的变化 ,以探讨这两种细胞与MG的关系。采用流式细胞仪分析MG患者和对照组外周血中CD5 + B细胞和CD4 CD8 T细胞的频率 ,同时以ELISA方法检测这些患者的血清AchR、PsmR抗体水平。结果 :2 8例MG患者的CD5 + B细胞为 19 75 %± 10 8% ,高于对照组的 15 4 %± 9 6 7% (P <0 0 1) ;胸腺未切除MG患者的CD5 + B细胞为 2 2 31%± 7 4 7% ,显著高于对照组 (P <0 0 0 1) ;两种抗体阳性MG患者的CD5 + B细胞为 2 4 96 %± 13 1% ,显著高于对照组 (P <0 0 0 1) ;以上各组MG患者的CD4 CD8 T细胞与对照组均无显著区别 ;两种抗体阴性组的CD5 + B细胞和CD4 CD8 T细胞亦与对照组均无显著区别 ;两种抗体阴性组的CD5 + B细胞和CD4 CD8 T细胞亦与对照组无明显差异。本研究提示MG患者外周血的CD5 + B细胞频率增高 ,与胸腺切除与否以及突触前后膜抗体的阳性程度密切相关 ,而CD4 CD8 T细胞是否与MG有关还需进一步研究证实。     

CD4+/CD25+T细胞与哮喘发病关联性的实验研究

目的观察CD4 /CD25 调节T细胞及其他T细胞亚群与小鼠哮喘发病的相关性,旨在初步探讨调节T细胞参与哮喘发病的可能机制.方法应用流式细胞术检测小鼠正常对照组,哮喘模型/CD25 调节T细胞及T细胞亚群表达状况,同时应用放射免疫法测定各组TXB2和 组及治疗组CD4/CD25 的T细胞亚群显著低于正常对 、CD4 和CD4 SOD的含量.结果哮喘小鼠脾脏单个核中CD3/CD25 及CD4 均较哮喘组升高(P＜0.05).而小鼠哮喘组TXB2水平异常 照组(P＜0.01),治疗组CD4增高和SOD的减少均可被血栓素合成酶抑制剂特异性阻断.结论提示小鼠发病时免疫功能紊乱与T/CD25 参与调节性相关,而TXB2和氧自由基是哮喘发病的炎性介质,介导和参与 细胞亚群变化及CD4哮喘的发生和发展,用TXB2合成酶抑制剂不仅可抑制TXB2,同时也影响氧自由基的产生.