CD4+ CD25+ regulatory T cells control the induction of antigen-specific CD4+ helper T cell responses in cancer patients

A proportion of cancer patients naturally develop CD4+ T-helper type 1 (Th1) cell responses to NY-ESO-1 that correlate with anti-NY-ESO-1 serum antibodies. To address the role of T-cell regulation in the control of spontaneous tumor immunity, we analyzed NY-ESO-1-specific Th1 cell induction before or after depletion of CD4+CD25+ T cells in vitro. While Th1 cells were generated in the presence of CD25+ T cells in cancer patients seropositive for NY-ESO-1, seronegative cancer patients and healthy donors required CD25+ T-cell depletion for in vitro induction of NY-ESO-1-specific Th1 cells. In vitro, newly generated NY-ESO-1-specific Th1 cells were derived from naive precursors, whereas preexisting memory populations were detectable exclusively in patients with NY-ESO-1 antibody. Memory populations were less sensitive than naive populations to CD4+CD25+ regulatory T cells. We propose that CD4+CD25+ regulatory T cells are involved in the generation and regulation of NY-ESO-1-specific antitumor immunity.     

Integrin inhibition through Lyn-dependent cross talk from CXCR4 chemokine receptors in normal human CD34+ marrow cells

We studied the effects of Lyn ablation on CXCR4 receptor-mediated migration and adhesion of hematopoietic precursors. Down-regulation of Lyn expression with siRNA greatly reduced CXCR4-dependent hematopoietic cell movement, and increased cell adherence to stroma. This increase was associated with the up-regulated expression of activation-dependent epitopes of the beta(2) integrin LFA-1 and was prevented by antibodies that selectively block cell adhesion mediated by ICAM-1. Attachment to surfaces coated with ICAM-1 was also enhanced in Lyn-depleted hematopoietic cells, as compared with Lyn-expressing cells. Functional rescue experiments with Lyn siRNA targeting the 3' UTR indicated that the observed effects can be attributed directly to specific inhibition of Lyn. Our results show that in chemokine-stimulated hematopoietic cells Lyn kinase is a positive regulator of cell movement while negatively regulating adhesion to stromal cells by inhibiting the ICAM-1-binding activity of beta(2) integrins. These results provide a molecular mechanism for cross talk between the chemokine receptor CXCR4 and beta(2) integrins. This cross talk may allow chemokine receptors to modulate the arrest of rolling hematopoietic precursors on the surface of bone marrow stromal cells.     

IL-15 as a mediator of CD4+ help for CD8+ T cell longevity and avoidance of TRAIL-mediated apoptosis

CD4+ helper T cells contribute to the induction and maintenance of antigen-specific CD8+ T cells. Their absence results in short-lived antigen-specific CD8+ T cells and defective secondary CD8+ T cell responses because of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-mediated apoptosis. Here, we show that IL-15 codelivered with vaccines can overcome CD4+ T cell deficiency for promoting longevity of antigen-specific CD8+ T cells and avoidance of TRAIL-mediated apoptosis. In both priming and secondary responses, IL-15 down-regulates proapoptotic Bax, an intermediate in TRAIL-mediated apoptosis, and increases anti-apoptotic Bcl-X(L) in CD8+ T cells. Thus, IL-15 is sufficient to mimic CD4+ T cell help. Antigen-specific CD4+ T cells induce dendritic cells (DCs) to produce IL-15. IL-15 is also necessary for optimal help, because helper cells do not deliver effective help through IL-15-/- DCs. Therefore, IL-15 codelivered with vaccines can overcome CD4+ helper T cell deficiency for induction of functionally efficient CD8+ T cells and maintenance of CD8+ cytotoxic T lymphocytes (CTLs), and IL-15 is probably one of the natural mediators of help. These findings suggest new vaccine strategies against infections and cancers, especially in individuals with CD4-deficiency.     

Suppression of myasthenogenic responses of a T cell line by a dual altered peptide ligand by induction of CD4+CD25+ regulatory cells

Myasthenia gravis is a T cell-dependent, antibody-mediated autoimmune disease. A dual altered peptide ligand (APL) that is composed of the tandemly arranged two single amino acid analogs of two myasthenogenic peptides, p195-212 and p259-271, was demonstrated to down-regulate in vitro and in vivo myasthenia gravis-associated autoreactive responses. The aims of this study were to demonstrate the suppressive properties and to elucidate the mechanism of action of the dual APL on a T cell line specific to the myasthenogenic peptide p195-212. We demonstrate here that incubation of cells of the line with the dual APL resulted in the inhibition of proliferation and secretion of IL-2 and IFN-gamma triggered by p195-212. In contrast, secretion of TGF-beta and IL-10 was upregulated. The dual APL induced the generation of CD4+CD25+ cells that were characterized by the expression of CD45Rb(low), cytotoxic T lymphocyte-associated antigen-4, TGF-beta, CD62L, Foxp3, and neuropilin. In addition, the dual APL-treated cells were capable of inhibiting the proliferation response of the line when the two sets of cells were cocultured. The role of CD4+CD25+ cells was further confirmed by demonstrating that the suppression was abrogated by blocking/neutralization of CD25. Thus, the dual APL acts by inducing the formation of CD4+CD25+ regulatory cells. By using a T cell line, we could show that the immunosuppressive CD4+CD25+ cells were indeed induced by the dual APL and are not part of the naturally occurring regulatory cells.     

CD4+CD25+ regulatory T cells control induction of autoimmune hemolytic anemia

Autoimmune hemolytic anemia (AIHA) is the result of increased destruction of red blood cells (RBCs) due to the production of autoantibodies, and it can be life-threatening. To study the mechanisms that trigger AIHA, we used the Marshall-Clarke and Playfair model of murine AIHA, in which mice repeatedly immunized with rat RBCs develop erythrocyte autoantibodies as well as rat-specific alloantibodies. We analyzed the role of CD25(+) T-regulatory subsets in controlling AIHA in C57/Bl6 mice using antibody depletion studies. Treatment with anti-CD25 antibody but not isotype control prior to immunization with rat RBCs increased the incidence of AIHA from 30% to 90%. Adoptive transfer of purified splenic population of CD4(+)CD25(+) but not CD4(+)CD25(-) cells from immunized mice into naive recipients prevented the induction of autoantibody production. Altogether, our data establish a critical role for CD4(+)CD25(+) cells for control of AIHA, which may help to establish therapeutic strategies for treatment of AIHA.     

CD4+ CD25+ T cells responding to serologically defined autoantigens suppress antitumor immune responses

A variety of tumor-derived antigens have been defined by IgG antibodies in tumor bearers' sera with serological identification of antigens by recombinant expression cloning (SEREX), a serological expression cloning method. The majority of these antigens show no structural abnormality and seem to be wild-type autoantigens. Coimmunization with DNA encoding these autoantigens and tumor-specific cytotoxic T lymphocytes epitopes heightened CD8+ T cell responses and increased resistance to tumor challenge in a CD4+ T cell-dependent manner. In contrast, immunization with these SEREX-defined autoantigens alone leads to heightened susceptibility to tumor challenge. This suppressive effect of immunization is mediated by CD4+ CD25+ T cells. In mice immunized with one of the SEREX-defined autoantigens, Dna J-like 2, the number of alpha-GalCer/CD1d tetramer+ CD3+ T cells [representing natural killer T (NKT) cells] was reduced in the pulmonary compartment, whereas no evident change in the number of other T cell subsets was observed. Experiments with Jalpha281-/- mice lacking most NKT cells indicate that NKT cells are primarily responsible for metastasis suppression and that their activity is inhibited by immunization with Dna J-like 2. We propose that SEREX identifies a pool of autoantigens that maintains and regulates immunological homeostasis via CD4+ CD25+ regulatory T cells.     

Tolerance induction by third-party "off-the-shelf" CD4+CD25+ Treg cells

OBJECTIVE: Recent reports have shown that donor or host CD4(+)CD25(+) Treg cells can be used to control GVHD or graft rejection following allogeneic BMT in mice. In the present study we investigated the potential of third-party Treg cells compared to donor-type cells to facilitate BM allografting. METHODS: Graft rejection is assessed in a mouse model of T cell-mediated BM allograft rejection. Lethally irradiated C3H mice are transplanted at day 2 after irradiation with T cell-depleted Balb/Nude BM. Graft rejection is induced by purified host-type T cells infused one day prior to BMT. Cells tested for their facilitating activity are added to the T cell-depleted BM allograft. RESULTS: Na?ve or ex vivo-expanded third-party Treg cells can effectively enhance engraftment of T cell-depleted BM allografts, exhibiting reactivity in vitro and in vivo similar to that found for donor-type Treg cells. CONCLUSION: The use of third-party Treg cells in contrast to donor-type cells could allow advanced preparation of a large bank of Treg cells (off-the-shelf), with all the appropriate quality controls required for cell therapy.     

Human CD4+CD25+ regulatory T cells: proteome analysis identifies galectin-10 as a novel marker essential for their anergy and suppressive function

CD4(+)CD25(+)Foxp3(+) regulatory T cells (CD25(+) Treg cells) direct the maintenance of immunological self-tolerance by active suppression of autoaggressive T-cell populations. However, the molecules mediating the anergic state and regulatory function of CD25(+) Treg cells are still elusive. Using differential proteomics, we identified galectin-10, a member of the lectin family, as constitutively expressed in human CD25(+) Treg cells, while they are nearly absent in resting and activated CD4(+) T cells. These data were confirmed on the mRNA and protein levels. Single-cell staining and flow cytometry showed a strictly intracellular expression of galectin-10 in CD25(+) Treg cells. Specific inhibition of galectin-10 restored the proliferative capacity of CD25(+) Treg cells and abrogated their suppressive function. Notably, first identified here as expressed in human T lymphocytes, galectin-10 is essential for the functional properties of CD25(+) Treg cells.     

CD4+ CD25+ 调节性T细胞与自身免疫性甲状腺疾病

CD4+ CD25+ 调节性T细胞为新近发现的一群功能成熟的T细胞亚群.其特征性表达叉头盒蛋白3(Foxp3)分子,专职免疫无能和免疫抑制,在维持外周免疫耐受,防止自身免疫性疾病发病中起着极为关键的作用.CD4+ CD25+ 调节性T细胞在自身免疫性甲状腺疾病(AITD)发病中的作用引起了人们的关注.动物实验发现CD4+ CD25+ 调节性T细胞存在与否决定了实验动物是否发生实验性自身免疫性甲状腺炎(EAT)和Graves病.人体研究发现CD4+ CD25+ 调节性T细胞数目和功能异常与人AITD发生密切相关.这些研究结果提示,CD4+ CD25+ 调节性T细胞可能在AITD发病中起重要作用.     

CD4+CD25+Treg细胞及其在肝病领域的研究近况

人体内天然存在一类以持续高表达IL-2Rα链(CD25)为特征的功能独特的T淋巴细胞亚群——CD4 CD25 调节性T淋巴细胞(CD4 CD25 Treg)。它能够分泌IL-4、IL-10和TGFβ,对效应T淋巴细胞具有抑制作用,还参与了自身免疫性疾病、移植免疫,肿瘤免疫等。一、CD4 CD25 Treg细胞的研究概况1.CD4 CD25 Treg细胞的产生及发育:研究发现,胸     

Local and systemic induction of CD4+CD25+ regulatory T-cell population by non-Hodgkin lymphoma

Regulatory T (Treg) cells contribute to immune evasion by malignancies. To investigate their importance in non-Hodgkin lymphoma (NHL), we enumerated Treg cells in peripheral blood mononuclear cells (PBMCs) and involved tissues from 30 patients. CD25(+)FoxP3(+)CD127(low)CD4(+) Treg cells were increased markedly in PBMCs (median = 20.4% CD4 T cells, n = 20) versus healthy controls (median = 3.2%, n = 13, P < .001) regardless of lymphoma subtype, and correlated with disease stage and serum lactate dehydrogenase (R(s) = 0.79, P < .001). T-cell hyporesponsiveness was reversed by depleting CD25(+) cells, or by adding anti-CTLA-4, supporting the view that Treg cells explain the systemic immunosuppression seen in NHL. A high proportion of Treg cells was also present in involved tissues (median = 38.8% CD4 T cells, n = 15) versus reactive nodes (median = 11.6%, n = 2, P = .02). When autologous CD25(-) PBMC fractions were incubated with tumor cells from patients (n = 6) in vitro, there was consistent strong induction and then expansion of cells with the CD4(+)CD25(+)FoxP3(+) phenotype of classic "natural" Treg cells. This population was confirmed to be suppressive in function. Direct cell-cell interaction of tumor cells with CD25(-) PBMCs was important in Treg induction, although there was heterogeneity in the mechanisms responsible. We conclude that NHL cells are powerful inducers of Treg cells, which may represent a new therapeutic target.     

Priming of CD4+ T cells and development of CD4+ T cell memory; lessons for malaria

CD4 T cells play a central role in the immune response to malaria. They are required to help B cells produce the antibody that is essential for parasite clearance. They also produce cytokines that amplify the phagocytic and parasitocidal response of the innate immune system, as well as dampening this response later on to limit immunopathology. Therefore, understanding the mechanisms by which T helper cells are activated and the requirements for development of specific, and effective, T cell memory and immunity is essential in the quest for a malaria vaccine. In this paper on the CD4 session of the Immunology of Malaria Infections meeting, we summarize discussions of CD4 cell priming and memory in malaria and in vaccination and outline critical future lines of investigation. B. Stockinger and M.K. Jenkins proposed cutting edge experimental systems to study basic T cell biology in malaria. Critical parameters in T cell activation include the cell types involved, the route of infection and the timing and location and cell types involved in antigen presentation. A new generation of vaccines that induce CD4 T cell activation and memory are being developed with new adjuvants. Studies of T cell memory focus on differentiation and factors involved in maintenance of antigen specific T cells and control of the size of that population. To improve detection of T cell memory in the field, efforts will have to be made to distinguish antigen-specific responses from cytokine driven responses.     

McCoy cell line as a possible model containing CD4+ receptors for the study of HIV-1 replication

Several studies have recently shown the use of recombinant rabies virus as potential vector-viral vaccine for HIV-1. The sequence homology between gp 120 and rabies virus glycoprotein has been reported. The McCoy cell line has therefore been used to show CD4+ or CD4+ like receptors. Samples of HIV-1 were isolated, when plasma of HIV-1 positive patients was inoculated in the McCoy cell line. The virus infection was then studied during successive virus passages. The proteins released in the extra cellular medium were checked for protein activity, by exposure to SDS Electrophoresis and blotting to nitro-cellulose filter, then reacting with sera of HIV positive and negative patients. Successive passages were performed, and showed viral replication, membrane permeabilization, the syncytium formation, and the cellular lysis (cytopathic effect). Flow cytometry analysis shows clear evidence that CD4+ receptors are present in this cell line, which enhances the likelihood of easy isolation and replication of HIV. The results observed allow the use of this cell line as a possible model for isolating HIV, as well as for carrying out studies of the dynamics of viral infection in several situations, including exposure to drugs in pharmacological studies, and possibly studies and analyses of the immune response in vaccine therapies.     

成人隐匿性自身免疫性糖尿病患者CD4+CD25+T细胞亚群的变化

目的探讨成人隐匿性自身免疫性糖尿病(LADA)患者外周血免疫调节性CD4 CD25 T细胞亚群的变化及其意义。方法以流式细胞仪检测32例LADA、16例T1DM、25例T2DM及27例正常对照外周血CD4 CD25 、CD3 CD8 T细胞。结果①LADA组外周血CD4 CD25 T细胞低于而CD3 CD8 T细胞高于T1DM组、T2DM组和正常对照组;②LADA患者CD3 CD8 T细胞比例与起病年龄、FC-P、2hC-P呈负相关。结论LADA患者免疫调节性CD4 CD25 T细胞减少,不能有效维持对胰岛自身抗原的耐受;细胞毒性CD3 CD8 T细胞增多从而破坏胰岛β细胞,导致自身免疫性糖尿病的发生和发展。     

A technique for accurate use of CD4+ cell counts

Despite uncertainty over their reliability, CD4+ cell counts are used extensively in both clinical and research settings to document progression in HIV infection. We examined, therefore, whether the performance of a simple statistical test would facilitate greater accuracy in the use of this marker. CD4+ cell count data were collected from a cohort of deceased (N = 60) and living HIV-positive gay men (N = 100). Pearson's product moment correlation coefficients were calculated for each individual in order to examine the association between CD4+ counts and time since diagnosis. Correlations of 0.7 or greater were obtained in approximately 50 percent of cases in each cohort. For these individuals, CD4+ cell counts were deemed to be a reliable indicator of rate of progression. The results suggest that the proposed technique ensures greater precision in the use of CD4+ cell counts and that the technique cna be used in individuals with either complete (deceased patients) or partial (living patients) CD4+ data.     

IL-5 promotes induction of antigen-specific CD4+CD25+ T regulatory cells that suppress autoimmunity

Immune responses to foreign and self-Ags can be controlled by regulatory T cells (Tregs) expressing CD4 and IL-2Rα chain (CD25). Defects in Tregs lead to autoimmunity, whereas induction of Ag-specific CD4+CD25+ Tregs restores tolerance. Ag-specific CD4+CD25+ FOXP3+Tregs activated by the T helper type 2 (Th2) cytokine, IL-4, and specific alloantigen promote allograft tolerance. These Tregs expressed the specific IL-5Rα and in the presence of IL-5 proliferate to specific but not third-party Ag. These findings suggest that recombinant IL-5 (rIL-5) therapy may promote Ag-specific Tregs to mediate tolerance. This study showed normal CD4+CD25+ Tregs cultured with IL-4 and an autoantigen expressed Il-5rα. Treatment of experimental autoimmune neuritis with rIL-5 markedly reduced clinical paralysis, weight loss, demyelination, and infiltration of CD4+ (Th1 and Th17) CD8+ T cells and macrophages in nerves. Clinical improvement was associated with expansion of CD4+CD25+FOXP3+ Tregs that expressed Il-5rα and proliferated only to specific autoantigen that was enhanced by rIL-5. Depletion of CD25+ Tregs or blocking of IL-4 abolished the benefits of rIL-5. Thus, rIL-5 promoted Ag-specific Tregs, activated by autoantigen and IL-4, to control autoimmunity. These findings may explain how Th2 responses, especially to parasitic infestation, induce immune tolerance. rIL-5 therapy may be able to induce Ag-specific tolerance in autoimmunity.     

CD4+ T细胞克隆对自体非霍奇金淋巴瘤具有特异的肿瘤杀伤作用

目的:研究CD4 T细胞的抗肿瘤能力。方法:利用1例滤泡B淋巴细胞淋巴瘤患者的外周血淋巴细胞,将缺乏人类白细胞抗原Ⅰ(HLA-Ⅰ)的恶性CH1细胞株作为惟一的刺激源,以梯度稀释法,得到3种自体的、细胞毒性的、具有肿瘤杀伤特异性的CD4 T细胞克隆。结果:3种T细胞克隆可以杀伤来自于新鲜恶性B细胞的自体HLA-Ⅰ分子缺乏的淋巴瘤细胞株,但却对EB病毒(EBV)阳性的正常B细胞或K562细胞无杀伤溶解作用。3种肿瘤特异杀伤的CD4 T细胞均为TCR Vβ17-Dβ1-Jβ1.2,并具有同样的CDR3。结论:研究表明,CD4 T细胞克隆能够被扩增,其能够特异性地杀伤从自体淋巴瘤细胞衍生的细胞株。通过产生CD4 T细胞来杀伤肿瘤细胞及其相应的过继转移,特别是在肿瘤逃避CD8 T细胞介导的免疫杀伤作用时,CD4 T细胞能起到替代作用。     

Potent induction of long-term CD8+ T cell memory by short-term IL-4 exposure during T cell receptor stimulation

An important goal of vaccination is to achieve long-term survival of functional memory T cells. Using a MHC-compatible adoptive transfer system, we show here that a short, 3-day IL-4 but not IL-2 or IL-12 exposure during in vitro T cell receptor stimulation of naive CD8(+) T cells induced long-lasting in vivo memory. Such long-term memory CD8(+) T cells expressed antigen-specific cytotoxicity and the potential for IFN-gamma and IL-4 production. Our results support the concept that functional T cell longevity can be regulated by cytokines during initial antigen encounter and provide a rational foundation for vaccine development. They also may have implications in formulating optimal therapeutic regimens of ex vivo expanded autologous cancer- and HIV-specific CD8(+) T cells. In addition, the availability of large numbers of memory CD8(+) T cells generated through our high-efficiency system should facilitate progress in the molecular dissection of CD8(+) T cell memory development.