CD+4 CD+25调节性T细胞抑制持续性丙型肝炎病毒感染患者CD+4T细胞反应

目的探讨CD+4 CD+25调节性T细胞(CD+4 CD+25Treg细胞)在持续性HCV感染患者CD+4 T细胞下调中的意义.方法流式细胞术检测慢性丙型肝炎患者外周血中CD+4 CD+25Treg细胞的数量以及细胞内因子的合成;与正常人或患者CD+4 CD-25 T细胞共同培养,检测其抑制功能;RT-PCR检测Foxp3的mRNA表达.结果 CD+4 CD+25Treg细胞约占慢性丙型肝炎患者外周血中CD+4 T细胞的(13.5±1.8)%,高于正常对照(5.3±0.8)% (P=0.004);主要合成IL-10,高表达Foxp3;CD+4 CD+25Treg细胞显著抑制CD+4 T细胞的增殖,以及合成IFNγ,并且抑制活性较正常人增高(P=0.034),这种作用不依赖IL-10和转化生长因子β.结论持续性HCV感染患者CD+4 CD+25Treg细胞表达增加,抑制活性增强,特异性抑制Th1反应.     

Increased frequency of interferon-gamma-producing peripheral blood CD4+ T cells in chronic hepatitis C virus infection

OBJECTIVES: To determine the profile of cytokine secretion by CD4+ T helper (Th) cells in chronic hepatitis C virus (HCV) infection, we used flow cytometry to determine the percentage of interferon (IFN)-gamma and interleukin (IL)-4 producing cells from CD4+ T lymphocytes in peripheral blood obtained from patients chronically infected with HCV. METHODS: Peripheral blood mononuclear cells isolated from 89 HCV infected subjects (22 asymptomatic carriers, 56 patients with chronic hepatitis, and 11 patients with liver cirrhosis) and 24 healthy controls were stained with surface CD4 and intracellular IFN-gamma and IL-4. Serum soluble IL-2 receptor (sIL-2R) levels were analyzed by ELISA. RESULTS: The frequency of IFN-gamma producing CD4+ cells in asymptomatic HCV carriers, patients with chronic hepatitis, and patients with liver cirrhosis were significantly higher than those of healthy controls (p<0.01, respectively). In contrast, the percentages of IL-4-producing CD4+ cells were very low, and there were no significant correlations with disease progression. A significant elevation in serum sIL-2R levels was found in chronic HCV infection compared to healthy controls, and serum sIL-2R levels significantly correlated with the frequency of IFN-gamma-producing cells. CONCLUSIONS: In HCV infected subjects, both serum sIL-2R and IFN-gamma are increased in chronic HCV infection no matter the stage of disease, meaning they are no different in asymptomatic carriers, patients with chronic hepatitis, and patients with liver cirrhosis, and that Th1 cytokine or Th1 cells may participate in the pathogenesis of liver damage in chronic HCV infection.     

乙型肝炎病毒感染不同阶段患者外周血CD4+CD25+调节性T细胞的测定

目的 测定HBV感染不同阶段患者外周血CD4+CD25+调节性T细胞(Treg)的频率及标记分子,并分析其与临床指标的相关性.方法 采集79例慢性乙型肝炎(CHB)、12例急性乙型肝炎(AHB)患者、26例无症状HBV携带者(ASC)和20例健康对照的外周血,流式细胞仪分析Treg频率、Treg细胞表面和胞内特征性分子的表达.普通RT-PCR和相对荧光定量PCR测定叉头/翼状转录因子3(Foxp3)在CD25+Treg细胞的表达水平.所有患者及健康对照均经ELISA检测HBV血清标记物水平,实时荧光定量PCR测定血清HBV DNA载量,并进行肝功能检测.结果 总CD4+CD25+T细胞占外周血CD4+T细胞的比率,在各患者组和健康对照组之间差异均无统计学意义(P＞0.05).HBeAg阳性CHB组CD4+CD25高表达T细胞频率(3.42%±0.81%)与HBeAg阴性CHB组(3.19%±0.67%)、ASC组(3.05%±0.64%)比较,差异无统计学意义(均P＞0.05),但明显高于健康对照组(2.72%±0.71%,P=0.034)和AHB组(2.25%±0.54%,P=0.013).CD4+CD25高表达T细胞表面高表达CD45RO、CD25分子,低表达CD45RA,细胞内高表达细胞毒性T淋巴细胞相关抗原-4(CTLA-4)和Foxp3.各患者组及健康对照组Treg中Foxp3表达水平的差异无统计学意义(P＞0.05).CHB组患者的Treg频率与血清病毒载量呈正相关(r=0.48,P=0.018).结论 Treg可能通过抑制T细胞免疫应答反应而影响病毒清除,并与CHB患者的持续感染密切相关.     

Loss of cytomegalovirus-specific CD4+ T cell responses in human immunodeficiency virus type 1-infected patients with high CD4+ T cell counts and recurrent retinitis

Clinical histories are reported for 2 patients treated with highly active antiretroviral therapy (HAART) who experienced multiple relapses of cytomegalovirus (CMV) retinitis, despite suppression of human immunodeficiency virus type 1 (HIV-1) viremia and improvement in CD4+ T cell counts (to >400 cells/microL). CMV-specific CD4+ T cell immune reconstitution was measured directly, using cytokine flow cytometry, which revealed persistent deficits in CMV-specific CD4+ T cell responses in both patients. CMV-specific T cells constituted 0.14% and 0.05% of the total CD4+ T cell count in these patients, which is significantly lower than the percentages for 34 control subjects (0.6%-46%; CD4+ T cell count range, 7-1039 cells/microL; P=.019). Deficits in pathogen-specific immune responses may persist in some individuals, despite suppression of HIV-1 replication and substantial increases in circulating CD4+ T cells after HAART, and such deficits may be associated with significant morbidity from opportunistic infections.     

Biphasic decay of latently infected CD4+ T cells in acute human immunodeficiency virus type 1 infection

Latent infection of resting CD4(+) T cells represents a major barrier to eradication of human immunodeficiency virus type 1 (HIV-1). The establishment and rate of decay of latent HIV-1 in resting CD(+) T cells from 9 acute seroconverters, 7 of whom began to receive highly active antiretroviral therapy (HAART) shortly after presentation, were studied. Before the initiation of therapy, these patients had very high frequencies of latently infected CD4(+) T cells, with a median frequency of 205 infectious units per million resting CD4(+) T cells. These values are > or =1 log higher than those seen in chronically infected patients who are not undergoing HAART. The number of latently infected cells declined dramatically after initiation of HAART but then tended to level off at a low but stable level. The biphasic decay of latent HIV in resting CD4(+) T cells in acute seroconverters supports current models of pre- and postintegration latency.     

Primary induction of human CD8+ cytotoxic T lymphocytes and interferon-gamma-producing T cells after smallpox vaccination

This study measured the ability of a standard smallpox vaccine, given by scarification (by bifurcated needle), to induce primary human vaccinia virus-specific cytotoxic and interferon (IFN)-gamma-producing T lymphocyte responses. Because protection against smallpox may be mediated in part by T cell memory responses induced by vaccination, an analysis of the induction of primary human cytotoxic T lymphocytes (CTL) and IFN-gamma-producing T cell responses was performed. Although smallpox is no longer an epidemic threat under natural conditions, vaccination is still recommended for persons working with vaccinia viruses in the laboratory and for those who may be at risk from the potential use of smallpox virus as a bioterrorism agent. The results demonstrate that smallpox vaccine given by bifurcated needle induces strong vaccinia virus-specific CD8(+) CTL and IFN-gamma-producing T cell responses and provide baseline information useful for planning the immunologic assessment of future smallpox vaccines.     

Most human thymic and peripheral-blood CD4+ CD25+ regulatory T cells express 2 T-cell receptors

Lack of allelic exclusion in the T-cell receptor (TCR) alpha locus gives rise to 2 different TCRs in 10% to 30% of all mature T cells, but the significance of such dual specificity remains controversial. Here we show that human CD4+ CD25+ regulatory T (Treg) cells express 2 distinct Valpha chains and thus 2 TCRs at least 3 times as often as other T cells. Extrapolating from flow cytometric analysis using Valpha2-, Valpha12-, and Valpha24-specific monoclonal antibodies (mAbs), we estimated that between 50% and 99% of the CD25+ Treg cells were dual specific, as compared with about 20% of their CD25- counterparts. Moreover, both TCRs were equally capable of transmitting signals upon ligation. Cells with 2 TCRs also expressed more FOXP3, the Treg-cell lineage specification factor, than cells with a single TCR. Our findings suggest that expression of 2 TCRs favors differentiation to the Treg-cell lineage in humans and raise the question of the potential functional consequences of dual specificity.     

乙型肝炎患者外周血CD4^＋T细胞Notch1蛋白的表达

目的探讨CD4^＋T细胞Notch1蛋白在乙型肝炎病人发病机制中的作用。方法采用流式细胞仪检测23例慢性乙型肝炎患者、8例急性乙型肝炎患者和10例健康对照者的外周血CD4^＋T细胞Notch1蛋白表达水平,并应用荧光定量PCR方法测定上述研究对象血中HBV-DNA滴度。结果慢性乙型肝炎组外周血CD4^＋T细胞Notch1蛋白的平均百分率为（3.17±0.65）%,与急性乙型肝炎组（1.85±0.46）%和健康对照组（2.18±0.57）%比较都有极其显著差异（P〈0.001）;急性乙型肝炎组外周血CD4^＋T细胞Notch1蛋白的百分率与健康对照组比较差异无统计学意义（P〉0.05）;慢性乙型肝炎患者外周血CD4^＋T细胞Notch1蛋白的百分率与HBV-DNA滴度呈正相关。结论Notch1蛋白在慢性乙型肝炎患者外周血中表达增高,说明其可能参与乙型肝炎病情的发展及病毒的清除。     

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.     

Close link between CD4+ and CD8+ T cell proliferation defects in patients with human immunodeficiency virus disease and relationship to extended periods of CD4+ lymphopenia

T cell proliferation failure is commonly associated with human immunodeficiency virus (HIV) infection. By examining T cell function on a single-cell basis, we found that CD4(+) T cell proliferation failure was often accompanied by CD8(+) T cell proliferation defects in patients with HIV disease. The defects are characterized by a proportional failure and reduced efficiency of precursor T cell proliferation after stimulation. In this study, patients who historically had low levels of circulating CD4(+) T cells were most likely to demonstrate cellular proliferation failure, regardless of current CD4(+) T cell counts. In contrast, neither historical nor current plasma HIV RNA levels were predictive of proliferation failure. These results suggest that mechanisms of T cell proliferation failure are more complex than can be explained by the direct effects of HIV replication and that therapeutic intervention to avoid prolonged periods of CD4(+) lymphopenia may be desirable for the preservation of immune function in patients with HIV disease.     

CD4+ T cell surface CCR5 density as a determining factor of virus load in persons infected with human immunodeficiency virus type 1

The intensity of expression of the chemokine receptor CCR5 is involved in in vitro cell infectability by human immunodeficiency virus (HIV)-1 R5 isolates. Because CCR5 expression varies among individuals, the hypothesis that this expression could determine virus load in HIV-1-infected persons was tested. The mean number of CCR5 molecules per cell was measured on peripheral blood CD4+ T lymphocytes (CCR5 density) from HIV-1-infected, asymptomatic, nontreated adults. There was a strong correlation between HIV RNA plasma level and CCR5 density (P=.009) that was independent of cell activation and was not due to an HIV-induced CCR5 up-regulation. These data are compatible with the hypothesis that CCR5 density is a key factor governing cell infectability and in vivo virus production and explain the protective effect of the Delta32CCR5 deletion, which results in low CCR5 expression. CCR5 density might be of critical predictive value in HIV infection.     

Activation pathways and human immunodeficiency virus type 1 replication are not altered in CD4+ T cells expressing the nef protein.

While recent studies in Rhesus monkeys have pointed out the importance of an intact nef gene for the development of acquired immunodeficiency syndrome (AIDS), no biological function has been so far unambiguously attributed to its product. Since Nef has been described to possess GTP-binding properties and to down-regulate CD4 cell surface expression, we looked for evidences of Nef interfering with the transduction of activating signals in human CD4+ T cells. We used a murine leukemia retroviral vector to express the HIV-1BRU nef gene in two permanent tumoral T-cell lines (CEM and Jurkat) and in two nonimmortalized, interleukin-2 (IL2)-dependent, T-cell clones. The single copy recombinant provirus integrated in the genome of these cells directed the synthesis of a 27-kD protein with a half-life greater than 5 h. The levels of expression of cell surface molecules involved in T-cell functions (CD4, CD3, CD28, CD29, IL-2 receptor) were not modified in cell populations expressing Nef. In immunocompetent T-cell clones, cell proliferation and lymphokine production in response to activating stimuli (IL-2, alloantigens, phorbol esters, or antibodies directed against CD2, CD3, CD4, CD28) remained unmodified. Moreover, the presence of Nef did not change the kinetics of human immunodeficiency virus (HIV) infection.     

CD4+CD25+ T细胞在溃疡性结肠炎中的表达及其临床意义

目的 研究溃疡性结肠炎(UC)患者外周血CD 4CD 25调节性T细胞比例的变化,探讨其在UC病理机制中的意义.方法 选择UC患者33例,对照组20例.用流式细胞仪检测外周血CD 4CD 25T细胞阳性率.用RT-PCR检测外周单个核细胞(PBMC)中Foxp3 mRNA的表达.用酶联免疫吸附试验检测血清中IL-10和TGF-β的浓度.结果 UC患者CD 4CD 25T细胞占CD 4T细胞的比例明显低于对照组(P＜0.01),并且与疾病的活动指数及血沉水平均呈显著负相关(R值分别为-0.660和-0.572,P值均＜0.01).UC患者Foxp3 mRNA的表达也明显低于对照组(P＜0.01).两组患者血清IL-10和TGF-β的浓度比较无明显差异(P＞0.05).结论 UC患者外周血CD 4CD 25 调节性T细胞明显降低,与疾病活动性相关,提示这类细胞可能在UC的病理机制中发挥作用.Foxp3表达降低可能是导致CD 4CD 25 T细胞发育障碍的重要因素.