Prognostic value of tumor-infiltrating CD4+ T-cell subpopulations in head and neck cancers.

PURPOSE: CD4(+) T cells play a central role in initiating and maintaining anticancer immune responses. However, regulatory CD4(+)CD25(+) T cells which express Foxp3 have also been shown to inhibit antitumor effector T cells. In view of these heterogeneous CD4(+) T-cell populations, this study was designed to determine the prognostic value of various tumor-infiltrating CD4(+) T-cell populations in head and neck squamous cell carcinoma.EXPERIMENTAL DESIGN: Eighty-four newly diagnosed untreated patients with histologically proven primary head and neck squamous cell carcinoma were included in this study. Double or triple immunofluorescence staining was done to assess and quantify the activated CD4(+)CD69(+) T cells, regulatory CD4(+)Foxp3(+) T cells, and mixed CD4(+)CD25(+) T cells comprising both activated and regulatory T cells.RESULTS: On univariate analysis, high levels of tumor-infiltrating CD4(+)CD69(+) T cells were correlated with both better locoregional control (P = 0.01) and longer survival (P = 0.01). Infiltration by regulatory Foxp3(+)CD4(+) T cells was positively associated with a better locoregional control of the tumor. Multivariate analysis showed that the only significant prognostic factors related to locoregional control were T stage (P = 0.02) and CD4(+)Foxp3(+) T-cell infiltration of the tumor (P = 0.02). In the Cox multivariate analysis, only two variables influenced overall survival probability: T stage (P = 0.036) and CD4(+)CD69(+) T-cell infiltration (P = 0.017).CONCLUSION: This study shows that tumor-infiltrating activated CD4(+)CD69(+) T cells are associated with a good prognosis in head and neck squamous cell carcinoma. In addition, regulatory Foxp3(+)CD4(+) T cells are positively correlated with locoregional control may be through down-regulation of harmful inflammatory reaction, which could favor tumor progression.     

The frequency and suppressor function of CD4+CD25highFoxp3+ T cells in the circulation of patients with squamous cell carcinoma of the head and neck.

Objective: Immune escape is a characteristic feature of head and neck squamous cell carcinoma (HNSCC). Regulatory T cells (Treg) might contribute to HNSCC progression by suppressing antitumor immunity, and their attributes in patients are of special interest. Methods: Multicolor flow cytometry was used to study the frequency and phenotype of Treg in peripheral blood lymphocytes of 35 patients with HNSCC and 15 normal controls (NC). CD4(+)CD25(high) T cells were purified by fluorescence-activated cell sorting and tested for regulatory function by coculture with carboxyfluorescein diacetate succinimidylester-labeled autologous CD4(+)CD25(-) responder cells. RESULTS: The percentages of circulating CD4(+)CD25(+) T cells were increased in HNSCC patients (5 +/- 3%) versus NC (2 +/- 1.5%). In patients, this cell subset largely contained CD4(+)CD25(high)Foxp3(+) T cells and only few CD25(low/interm) cells. In addition, the frequency of Treg positive for CD62L, CTLA-4, Fas, FasL, and Foxp3 was greater in the circulation of patients than in NC (P < 0.0001). In HNSCC patients, Treg mediated significantly higher suppression (78 +/- 7%) compared with Treg in NC (12 +/- 4%) with P < 0.0001. Surprisingly, higher Treg frequency (P < 0.0059) and levels of suppression (P < 0.0001) were observed in patients with no evident disease (NED) than in untreated patients with active disease (AD). CONCLUSIONS: The frequency of T cells with suppressor phenotype and function (Treg) was significantly greater in HNSCC patients who were NED after oncologic therapy relative to those with AD. This finding suggests that oncologic therapy favors expansion of Treg.     

Functional and phenotypic characteristics of CD4+CD25highFoxp3+ Treg clones obtained from peripheral blood of patients with cancer

Circulating human CD4(+)CD25(high)Foxp3(+) T cell populations (Treg) may contain activated CD4(+)CD25(+) T cells interfering with Treg evaluation. To gain insights into the phenotypic and functional characteristics of Treg in patients with cancer, we have analyzed CD4(+)CD25(high) populations at the clonal level. Single-cell sorted (SCS) CD4(+)CD25(high) T cells obtained from PBMC of normal controls (NC) or patients with squamous cell carcinoma of the head and neck (HNSCC) were plated at 1 cell/well in 96 well plates and expanded with anti-CD3/anti-CD28 Abs and 1,000 IU IL-2/mL in the presence or absence of rapamycin (1 nM). All generated clones were evaluated for the phenotype by flow cyometry and suppressor function in CFSE-based proliferation assays. Clones had heterogeneous CD25 expression levels. Cloning efficiency of CD4(+)CD25(high) T cells was low. CD25(high) clones expressed CTLA-4, Foxp3, CD62L, but little GITR and suppressed proliferation of autologous CD4(+)CD25(-) responder cells. Clones of activated CD4(+)CD25(interm./low) cells expressed intermediate to high levels of GITR and HLA-DR and did not suppress proliferation of responder cells. The number, suppressor phenotype and function of CD25(high) Treg clones were significantly enhanced in HNSCC patients relative to NC (p 相似文献   

Proportion of CD4+CD25+ regulatory T cell is increased in the patients with ovarian carcinoma

Objective: To study the frequency of the CD4⁺CD25⁺ regulatory T cells (Tregs) in the patients with ovarian carcinoma and its possible mechanism. Methods: The percentages of CD4⁺CD25⁺ Tregs in the peripheral blood lymphocytes (PBLs), tumor infiltrating lymphocytes (TILs) and tumor associated lymphocytes (TALs) from 13 patients with ovarian carcinoma and in the PBLs from 14 healthy women were determined by flow cytometry. The expression of CD69 on CD4⁺PBLs from the patients was detected. PBLs from healthy women were cultured in complete RPMI 1640 containing the supernatant from SKOV3 cell line with or without PHA (phytohemagglutinin) stimulation for 72 hours, then the percentage of CD4⁺CD25⁺ T cells was detected. Results: CD4⁺CD25⁺ Tregs in the PBLs from patients with ovarian carcinoma were significantly increased compared with those from the control. The percentage of CD4⁺CD25⁺ Tregs in TILs was higher than that in PBLs and TALs from the patients, but not significantly. The expression of CD69 on CD4⁺PBLs from the patients was negative. The percentages of CD4⁺CD25⁺ T cells in PBLs cultured with SKOV3 supernatant elevated significantly compared with those without supernatant whether PHA was added or not (P = 0.001 and 0.001, respectively). Conclusion: There is an increasing of the proportion of CD4⁺CD25⁺ Tregs in PBLs, TILs and TALs of the patients with ovarian carcinoma, which probably results from up-regulation of soluble factor secreted by ovarian carcinoma cells.     

乳腺癌患者外周血CD4+CD25+调节性T细胞的检测及意义

目的探讨乳腺癌患者外周血中CD4+CD25+调节性T细胞的变化及意义.方法采用流式细胞技术检测64例乳腺癌患者外周血中CD4+CD25+调节性T细胞,采用ELISA法检测外周血中转化生长因子-β1(TGF-β1)的表达水平.结果乳腺癌患者外周血中CD4+CD25+调节性T细胞占T淋巴细胞的百分比为(5.1±2.9)%,高于乳腺良性肿物患者和健康志愿者(P均<0.05).乳腺癌患者外周血中CD4+CD25+T细胞水平与肿物大小、TGF-β1呈正相关(r分别为0.511和0.253),与CD8+CD28+T细胞和NK细胞呈负相关(r分别为-0.243和-0.301).结论乳腺癌患者外周血中具有免疫抑制活性的CD4+CD25+调节性T细胞水平较高,对乳腺癌患者具有免疫抑制作用.     

Human ovarian carcinoma cells generate CD4(+)CD25(+) regulatory T cells from peripheral CD4(+)CD25(-) T cells through secreting TGF-beta

Increased CD4(+)CD25(+) regulatory T cells predicted poor prognosis in ovarian carcinoma patients. This study aimed to define whether soluble substances secreted by ovarian carcinoma could up-regulate the proportion of CD4(+)CD25(+) regulatory T cells. Similar to TGF-beta, the low MWF (<50kDa) of supernatant derived from SKOV3 could convert part of freshly isolated CD4(+)CD25(-) T cells into CD25(+) population with similar characters as natural CD4(+)CD25(+) regulatory T cells. To deplete TGF-beta in the low MWF by neutralizing anti-TGF-beta would eliminate this transformation phenomenon. These results indicate that TGF-beta secreted by ovarian carcinoma cells owns vital function in the process of converting peripheral CD4(+)CD25(-) T cells into CD4(+)CD25(+) regulatory T cells, which may provide one immunotherapeutic target for ovarian cancer.     

Regulatory CD4(+)CD25(+) T cells in tumors from patients with early-stage non-small cell lung cancer and late-stage ovarian cancer.

Immunosuppression may contribute to the progression of cancer. In this study we assessed the structural and functional status of T cells from tumor specimens obtained from patients with early stage non-small cell lung cancer and late-stage ovarian cancer. Although some groups have described structural alterations in the TCR in patients with other malignancies, we did not observe decreased expression of the CD3zeta subunit in the tumor-associated T cells. However, increased percentages of CD4(+)CD25(+) T cells were observed in the non-small cell lung cancer tumor-infiltrating lymphocytes and ovarian cancer tumor-associated lymphocytes. Furthermore, these CD4(+)CD25(+) T cells were found to secrete transforming growth factor-beta, consistent with the phenotype of regulatory T cells. Despite a generalized expression of lymphocyte activation markers in the tumor-associated T-cell populations, the CD8(+) T cells expressed low levels of CD25. To determine whether expression of CD25 could be restored on the CD8 cells, tumor-associated T cells were stimulated with anti-CD3 and anti-CD28 monoclonal antibodies. After stimulation, nearly all of the CD8 T cells expressed CD25. Furthermore, despite the low levels of interleukin 2, IFN-gamma, and tumor necrosis factor-alpha secretion by the tumor-associated and peripheral blood T cells at baseline, stimulation with anti-CD3 and anti-CD28 monoclonal antibodies significantly increased the fraction of cells producing these cytokines. Thus, tumor-associated T cells from patients with early and late-stage epithelial tumors contain increased proportions of CD4(+)CD25(+) T cells that secrete the immunosuppressive cytokine transforming growth factor-beta. Furthermore, our results are consistent with previous reports showing impaired expression of CD25 on CD8(+) T cells in cancer patients. Finally, increased lymphocyte costimulation provided by triggering the CD28 receptor is able to increase CD25 expression and cytokine secretion in tumor-associated T cells. These observations provide evidence for the contribution of regulatory T cells to immune dysfunction in cancer patients.     

Depletion of CD25(+) CD4(+) T cells and treatment with tyrosinase-related protein 2-transduced dendritic cells enhance the interferon alpha-induced, CD8(+) T-cell-dependent immune defense of B16 melanoma.

Transduction of B16 melanoma cells with IFN alpha (B16-IFN alpha) enhances CD8(+) T-cell-dependent tumor immunity in mice, resulting in delayed outgrowth in vivo. Here we provide evidence that CD4(+) T cells down-regulate the IFN alpha-induced tumor immune defense. Importantly, depletion of regulatory CD25(+) CD4(+) T cells prevented growth of B16-IFN alpha in most mice and promoted long-lasting protective tumor immunity. Rejection of B16-IFN alpha could also be achieved with therapeutic injections of dendritic cells genetically engineered to express the melanoma antigen tyrosinase-related protein 2. These results support the development of novel strategies for the immunotherapy of melanoma using IFN alpha in combination with elimination of regulatory T cells or antigen-specific immunization.     

CD25+ T cell depletion impairs murine squamous cell carcinoma development via modulation of antitumor immune responses

Squamous cell carcinoma (SCC) constitutes a microenvironment that could modulate the antitumor immune response. Also, tumor-infiltrating lymphocytes are believed to play complex regulatory roles in antitumor immunity against SCC. The presence of regulatory T cells (Tregs) has been associated with the suppression of tumor-reactive T cells. However, the underlying mechanism for this T cell dysfunction is not clear. We used a multistage model of SCC to examine the role of Treg cells during tumor development. 7,12-dimethylbenz[a]-anthracene/phorbol 12-myristate 13-acetate treatment and systemic depletion of Treg cells using an anti-CD25 monoclonal antibody (PC61) resulted in a decrease in the number and incidence of papilloma. Furthermore, CD25 depletion increased the proportion of CD8(+) and CD4(+) T cells that were isolated from tumor lesions. The levels of interleukin (IL)-1β, IL-10, IL-12, IL-13, interferon-γ, transforming growth factor-β and tumor necrosis factor-α, but not IL-17, were increased in the tumor microenvironment after Treg depletion. Therefore, our results indicated involvement of CD25(+) T cells in SCC development and in the suppression of the inflammatory immune response.     

Systemic CTLA-4 blockade ameliorates glioma-induced changes to the CD4+ T cell compartment without affecting regulatory T-cell function.

PURPOSE: Patients with malignant glioma suffer global compromise of their cellular immunity, characterized by dramatic reductions in CD4(+) T cell numbers and function. We have previously shown that increased regulatory T cell (T(reg)) fractions in these patients explain T-cell functional deficits. Our murine glioma model recapitulates these findings. Here, we investigate the effects of systemic CTLA-4 blockade in this model. EXPERIMENTAL DESIGN: A monoclonal antibody (9H10) to CTLA-4 was employed against well-established glioma. Survival and risks for experimental allergic encephalomyelitis were assessed, as were CD4(+) T cell numbers and function in the peripheral blood, spleen, and cervical lymph nodes. The specific capacities for anti-CTLA-4 to modify the functions of regulatory versus CD4(+)CD25(-) responder T cells were evaluated. RESULTS: CTLA-4 blockade confers long-term survival in 80% of treated mice, without eliciting experimental allergic encephalomyelitis. Changes to the CD4 compartment were reversed, as anti-CTLA-4 reestablishes normal CD4 counts and abrogates increases in CD4(+)CD25(+)Foxp3(+)GITR(+) regulatory T cell fraction observed in tumor-bearing mice. CD4(+) T-cell proliferative capacity is restored and the cervical lymph node antitumor response is enhanced. Treatment benefits are bestowed exclusively on the CD4(+)CD25(-) T cell population and not T(regs), as CD4(+)CD25(-) T cells from treated mice show improved proliferative responses and resistance to T(reg)-mediated suppression, whereas T(regs) from the same mice remain anergic and exhibit no restriction of their suppressive capacity. CONCLUSIONS: CTLA-4 blockade is a rational means of reversing glioma-induced changes to the CD4 compartment and enhancing antitumor immunity. These benefits were attained through the conferment of resistance to T(reg)-mediated suppression, and not through direct effects on T(regs).     

CD4+CD25+ regulatory T cells in patients with gastrointestinal malignancies: possible involvement of regulatory T cells in disease progression

BACKGROUND: Active suppression by CD4+CD25+ regulatory T cells plays an important role in the down-regulation of the response of T cells to foreign and self antigens. Experimental tumor models in mice revealed that regulatory T cells inhibit antitumor immune responses. The purpose of the current study was to demonstrate the possible involvement of CD4+CD25+ regulatory T cells in immune system impairment in patients with gastrointestinal malignancies. METHODS: The phenotypes of lymphocytes, particularly those of CD4+CD25+ T cells, were analyzed in peripheral blood in 149 patients with gastrointestinal malignancies and in ascites in 7 patients with peritoneal dissemination. In addition, cytokine production after in vitro stimulation was examined in CD4+CD25+ and CD4+CD25- T cells isolated from patients with malignant disease. RESULTS: Compared with healthy volunteers, patients with gastrointestinal malignancies had a higher proportion of CD4+CD25+ T cells in peripheral blood, due to the presence of a drastically smaller number of CD4+CD25- T cells. Among patients with gastric carcinoma, those with higher percentages of CD4+CD25+ T cells had a poorer prognosis than did those with lower percentages. CD4+CD25+ T cells also were present in greater proportions in ascites from patients who had advanced-stage disease with peritoneal dissemination. Isolated CD4+CD25+ T cells from patients with malignant disease produced interleukin (IL)-4 and IL-10 but not IL-2 or interferon-gamma; these cells also inhibited cytokine production by CD4+CD25- T cells after in vitro stimulation. CONCLUSIONS: The relative increase in CD4+CD25+ regulatory T cells may be related to immunosuppression and tumor progression in patients with gastrointestinal malignancies. This finding suggests that the use of immunomodulatory therapy to treat patients with gastrointestinal malignancies may be an effective strategy.     

Regulatory T cell-resistant CD8+ T cells induced by glucocorticoid-induced tumor necrosis factor receptor signaling

We previously found that a Salmonella typhimurium vector engineered to secrete soluble tumor antigen induces CD4(+) T cells resistant to CD4(+)CD25(+) regulatory T cells (Treg) and that glucocorticoid-induced tumor necrosis factor receptor family-related gene (GITR) signal is involved in the development of this resistance. In this study, we address the potential of incorporating GITR ligand (GITRL) as a way to augment the immunogenicity of cancer vaccines. BALB/c mice were immunized by gene gun with plasmids encoding the mutated extracellular signal-regulated kinase 2 (mERK) with or without plasmids encoding mouse GITRL. Coadministration with GITRL during primary and secondary immunization enhanced the induction of mERK-specific CD8(+) T cells. Antibody depletion and minigene analysis suggested that GITRL directly activated CTL epitope-specific CD8(+) T cells independently of CD4(+) T cells. Immunization with plasmids encoding a CTL epitope and GITRL resulted in strong tumor inhibition in a CD8(+) T cell-dependent manner. Furthermore, CTL epitope-specific CD8(+) T cells induced by immunization with plasmids encoding CTL epitope coadministered with GITRL were refractory to suppression by CD4(+)CD25(+) Tregs compared with CD8(+) T cells induced without GITR signaling. We propose that coadministration of GITR signaling agents with tumor antigens constitutes a promising novel strategy for cancer vaccine development.     

胃癌患者调节性T细胞胞内外细胞因子的检测及其意义

背景与目的:目前认为CD4 CD25 调节性T细胞与胃癌患者的免疫功能抑制密切相关,但CD4 CD25 调节性T细胞发挥免疫抑制功能的作用机制并不十分清楚.本研究通过检测胃癌患者CD4 CD25 调节性T细胞产生具有不同生物活性的细胞因子干扰素-γ(interferon-γ,IFN-γ)、白介素4(interleukin-4,IL-4)、IL-10及肿瘤生长因子-β(tumor growth factor-β,TGF-β)的分泌情况,进一步探讨这些细胞因子在胃癌患者CD4 CD25 调节性T细胞发挥免疫抑制功能的作用.方法:按常规方法制备患者外周血单个核淋巴细胞,采用免疫磁珠分选方法分离CD4 CD25 T细胞及CD4 CD25-T细胞后,用细胞内细胞因子染色法及ELISA法分别研究CD4 CD25 T细胞在胞内及胞外产生具有不同生物活性的细胞因子IFN-γ、IL-4、IL-1O及TGF-β的水平.结果:(1)与健康对照组比较,胃癌患者分泌内细胞因子IFN-γ、IL-4及IL-10的CD4 CD25 T细胞占CD4 细胞的百分比均显著增高(P＜0.05).(2)培养96 h后,上清液的各种细胞因子水平,无论是胃癌患者还是健康对照组,CD4 CD25 T细胞分泌的IL-10及TGF-β均显著高于CD4 CD25-T细胞(P＜0.05).CD4 CD25 T细胞分泌的IFN-γ显著低于CD4 CD25-T细胞(P＜0.05).结论:CD4 CD25 调节性T细胞体外免疫抑制作用的发挥可能与一些抑制性细胞因子有关,特别是细胞因子TGF-β在胃癌CD4 CD25 调节性T细胞的免疫抑制功能中起着相当重要的作用.     

CD4+CD25+调节性T细胞对晚期肺癌患者免疫抑制作用的研究

目的 探讨Treg及Th1/Th2类细胞因子在晚期肺癌肿瘤免疫抑制中的作用.方法 选取100例初治晚期肺癌患者及50例健康自愿者.采用流式细胞术检测其外周血中Treg、Th1类细胞因子(IFN-γ、IL-2、TNF-a)、Th2类细胞因子(IL-4、IL-6、IL-10)水平,同时分析CD4+CD25+Treg与Th1/Th2类细胞因子之间的相关性.结果 ①晚期肺癌患者外周血中Treg为(11.12±5.83)%,高于健康对照组(7.46±3.07)%,差异有统计学意义(P=0.003);②化疗前肺癌患者外周血中Treg为(11.12±5.83)%,明显高于化疗后(6.45±3.74)%,差异有统计学意义(P<0.001);③晚期肺癌患者与正常对照组Th1/Th2类细胞因子水平分别为:IFN-γ(8.56±3.62 vs 10.79±3.27,P=0.049)、IL-2(8.48±2.87 vs 10.22±4.03,P=0.03)、TNF-a(6.18±2.67vs8.14±2.87,P=0.007)、IFN-γ/IL-4(3.33±1.44 vs 4.09±1.00,P=0.028)、IL-4(3.17±1.19 vs 2.45±0.43,P<0.001)、IL-6(3.88±2.08 vs 2.33±0.88,P<0.001)、IL-10(3.64±1.73 vs 2.54±1.08,P=0.008),其中Th2类因子水平明显升高,差异有统计学意义(P均<0.05);④CD4+CD25+Treg与Th1类细胞因子IFN-γ、TNF-a、IL-2及IL-6无相关性(P均>0.05);与Th1/Th2(γ=-0.273,P=0.003)呈负相关;与Th2类细胞因子IL-4(γ=0.237,P=0.009)、IL-10(0.626,P<0.001)呈正相关(P均<0.05).结论 晚期肺癌患者CD4+CD25+Treg、Th2类细胞因子水平显著升高,Th1类细胞因子水平下降,它们共同导致肿瘤患者免疫抑制及肿瘤进展,监测其水平变化有助于判断肺癌患者疗效、预后,有效调控CD4+CD25+Treg及负性细胞因子水平可能是治疗肺癌的一个新策略.     

Functional characterization of EBV-encoded nuclear antigen 1-specific CD4+ helper and regulatory T cells elicited by in vitro peptide stimulation

CD4(+) helper and regulatory T (Treg) cells play important but opposing roles in regulating host immune responses against cancer and other diseases. However, very little is known about the antigen specificity of CD4(+) Treg cells. Here we describe the generation of a panel of EBV-encoded nuclear antigen 1 (EBNA1)-specific CD4(+) T-cell lines and clones that recognize naturally processed EBNA1-P(607-619) and -P(561-573) peptides in the context of HLA-DQ2 and HLA-DR11, -DR12, and -DR13 molecules, respectively. Phenotypic and functional analyses of these CD4(+) T cells revealed that they represent EBNA1-specific CD4(+) T helper as well as Treg cells. CD4(+) Treg cells do not secrete interleukin (IL)-10 and transforming growth factor beta cytokines but express CD25, the glucocorticoid-induced tumor necrosis factor receptor-related protein (GITR), and Forkhead Box P3 (Foxp3), and are capable of suppressing the proliferative responses of naive CD4(+) and CD8(+) T cells to stimulation with mitogenic anti-CD3 antibody. The suppressive activity of these CD4(+) Treg cells is mediated via cell-cell contact or in part by a cytokine-dependent manner. Importantly, these Treg cells suppress IL-2 secretion by CD4(+) effector T cells specific for either EBNA1 or a melanoma antigen, suggesting that these CD4(+) Treg cells induce immune suppression. These observations suggest that the success of peptide-based vaccines against EBV-associated cancer and other diseases may likely depend upon our ability to identify antigens/peptides that preferentially activate helper T cells and/or to design strategies to regulate the balance between CD4(+) helper and Treg cells.     

Depletion of CD4+CD25+ human regulatory T cells in vivo: kinetics of Treg depletion and alterations in immune functions in vivo and in vitro

The aim of this study was to investigate whether depletion of CD4(+)CD25(+) regulatory T cells (Treg) from melanoma patients affects immune responses against tumors. By application of recombinant IL-2-diphteria toxin fusion protein, also known as ONTAK, we were able to significantly reduce the frequency of Treg in peripheral blood, whereas other cell populations remained unaffected. The reduction of Treg started immediately after the first bolus of ONTAK with a dose of 5 microg ONTAK per kg bodyweight and lasted for 13 days with subsequent recovery thereafter. Successive ONTAK treatments further reduced the number of circulating Treg. Using the contact sensitizer DCP we show that all patients developed vast eczema after Treg depletion, whereas no or only mild eczematous reactions were detectable before ONTAK treatment. Corresponding induction of DCP-specific CD4(+) and CD8(+) T cells were detectable. Moreover, after immunization of ONTAK treated patients with tumor antigen peptides, MelanA/MART-1 and gp100, significant induction of peptide specific CD8(+) T cells could be observed in 90% of the patients treated. These cells displayed effector functions, as they were able to lyse peptide-pulsed target cells and secreted IFNgamma upon restimulation. In aggregate, our data indicate that ONTAK depletes Treg in vivo significantly, resulting in enhanced immune functions and substantial development of antigen-specific CD8(+) T cells in vaccinated individuals.     

Imatinib impairs the proliferation and function of CD4+CD25+ regulatory T cells in a dose-dependent manner

The tyrosine kinase inhibitor imatinib has been reported to inhibit CD8+ T lymphocytes. Little is known about its effects on CD4+CD25+ regulatory T cells (T(reg) cells) which might regulate the graft-vs.-leukemia (GVL) reaction after allogeneic stem cell transplantation (allo-SCT) and donor lymphocyte infusion (DLI). This is of particular interest in patients with relapse of chronic myeloid leukemia (CML) after allo-SCT, as the two therapeutical options DLI and imatinib might interact reversely. Here, we demonstrate that the proliferation of CD4+CD25+ T(reg) cells and their production of IL-10, TGF-beta1 and granzyme B as markers of activation were significantly down-regulated by imatinib in a dose-dependent manner. In addition, the expression of surface CD69, both surface and intracellular GITR, FoxP3, CD152 (CTLA) of activated CD4+CD25+ T(reg) cells were inhibited by imatinib in a dose-dependent manner. In light of these findings, clinical administration of imatinib might not result in a reduction of the GVL effect on CML patients receiving imatinib after allo-SCT and/or DLI or other CD8+ T lymphocyte based immunotherapies as the function of CD8+ cytotoxic T lymphocytes and CD4+CD25(hi) Treg cells is hampered in a similar way by imatinib.     

Simultaneous generation of CD8+ and CD4+ melanoma-reactive T cells by retroviral-mediated transfer of a single T-cell receptor

Adoptive immunotherapy of cancer requires the generation of large numbers of tumor antigen-reactive T cells for transfer into cancer patients. Genes encoding tumor antigen-specific T-cell receptors can be introduced into primary human T cells by retroviral mediated gene transfer as a potential method of providing any patient with a source of autologous tumor-reactive T cells. A T-cell receptor-specific for a class I MHC (HLA-A2)-restricted epitope of the melanoma antigen tyrosinase was isolated from a CD4(+) tumor-infiltrating lymphocyte (TIL 1383I) and introduced into normal human peripheral blood lymphocytes by retroviral transduction. T-cell receptor-transduced T cells secreted various cytokines when cocultured with tyrosinase peptide-loaded antigen-presenting cells as well as melanoma cells in an HLA-A2-restricted manner, and could also lyse target cells. Furthermore, T-cell clones isolated from these cultures showed both CD8(+) and CD4(+) transduced T cells could recognize HLA-A2(+) melanoma cells, giving us the possibility of engineering class I MHC-restricted effector and T helper cells against melanoma. The ability to confer class I MHC-restricted tumor cell recognition to CD4(+) T cells makes the TIL 1383I TCR an attractive candidate for T-cell receptor gene transfer-based immunotherapy.     

Increased frequency of CD4+ cells expressing CD161 in cancer patients.

PURPOSE: Although the function of natural killer receptors on T cells infiltrating tumors and their potential effect on antitumor immunity has been investigated, little is known about T cells expressing NKR-P1A (CD161) in cancer patients. In the present study, we examined T cells expressing CD161 in the peripheral blood, the tumor tissue and in malignant effusions of patients with several types of malignancies. EXPERIMENTAL DESIGN: Expression of CD161 in CD4(+) or CD8(+) (lacking CD56) T cells isolated from peripheral blood (n = 61), tumor specimens (n = 8), and malignant effusions (n = 37) of cancer patients was examined using four-color flow cytometry. Proliferative capacity and cytokine production of purified CD4(+)CD161(+)CD56(-) cells were studied after weak or strong stimulation, with or without costimulation, in the presence or absence of interleukin 2. The possible regulatory function of activated CD4(+)CD161(+)CD56(-) cells on T-cell alloresponses was also investigated. RESULTS: CD4(+) cells expressing CD161 were increased in cancer patients, compared with healthy individuals. This increase in the peripheral blood of cancer patients positively correlated with disease stage and was augmented at the tumor site. Phenotypic analysis revealed that CD4(+)CD161(+) cells are memory T cells, with low expression of activation markers. CD4(+)CD161(+) cells play an immunoregulatory role through cytokine production, because upon receiving costimulatory signals via CD28, they exert suppressive activity on autologous peripheral blood mononuclear cell alloresponses. CONCLUSIONS: CD4(+)CD161(+)CD56(-) cells represent a distinct memory T-cell population significantly increased in cancer patients. Depending on the type of signals provided by the tumor microenvironment, CD4(+)CD161(+) cells may regulate the immune response.