慢性乙型肝炎患者外周血CD4+CD25+调节性T细胞和T淋巴细胞亚群的研究

目的 观察外周血CD4 CD25 调节性T细胞(Tregs)百分比和T淋巴细胞亚群在慢性乙型肝炎(CHB)患者中的特点.方法 采集CHB患者15例和健康对照20例的外周血单个核细胞(PBMC)标本,应用三色流式分析法对PBMC中CD4 CD25 Tregs占CD4 百分比及外周血中的T淋巴细胞亚群进行分析.结果 分别比较CD4 CD25highTregs和CD4 CD25 CD127low/-Tregs占CD4 T细胞百分比,两组表型的Tregs在CHB组均高于正常对照组[(4.25%±3.22%vs1.57%±0.64%),(4.39%±2.03%vs1.86%±0.84%)](P＜0.01).CHB组外周血中的CD4 T淋巴细胞亚群的百分比(32.28%±6.26%)较正常对照组(39.39%±10.73%)下降,统计学有差别(P＜0.05).外周血中CD8 及CD4 /CD8 比值在两组间变化无统计学差异.结论 CHB患者CD4 CD25high和CD4 CD25 CD127low/-Tregs升高,外周血中的CD4 T淋巴细胞百分比下降.     

慢性心力衰竭患者CD4+CD25+调节性T细胞检测及意义

目的:探讨慢性心力衰竭(CHF)患者外周血CD4 CD25 调节性T细胞(Treg)水平及意义。方法:采用流式细胞分析法,检测42例CHF患者(CHF组)和16例正常对照者(对照组)外周血CD4 CD25 Treg/CD4 T细胞比例。结果:CHF患者外周血CD4 CD25 Treg/CD4 T细胞比例[(12.2±3.8)%]显著低于对照组[(16.3±5.2)%]。CD4 CD25 Treg/CD4 T比例在缺血性心脏病者[(12.6±4.1)%]与非缺血性心脏病者(12.0±3.7%)间差异无统计学意义,但心功能NYHA分级Ⅲ~Ⅳ级者[(10.4±3.2)%]比例明显低于Ⅰ~Ⅱ级者[(13.3±3·8)%]。结论:CHF患者外周血Treg比例减少,且与心功能有一定关系。CD4 CD25 Treg比例降低可能打破了外周免疫耐受,参与了心力衰竭的发生发展。     

CD28-T细胞亚群在类风湿关节炎患者外周血和关节液中的表达

目的 探讨CD28-T细胞亚群在类风湿关节炎(RA)患者外周血和关节液中的变化和意义。方法 随机选择RA患者45例,取新鲜抗凝外周血单个核细胞(PBMC),其中15例同时提取关节液单个核细胞( SFMC),以流式细胞技术检测CD28-T细胞数量及其表面可诱导共刺激分子(ICOS)的表达。2 组间比较用独立样本t检验。结果 ①与PBMC相比,RA患者SFMC中CD4+CD28+ ICOS+、CD4+CD28-ICOS+、CD8+ CD28+、CD8+ CD28+ ICOS+T细胞明显升高[(36±19)％与(15±8)％,t=-4.234,P＜0.01;(2.1±2.2)％与(0.6±1.4)％,t=-3.143,P＜0.01;(62±15)％与(47±18)％,t=-2.885,P＜0.01;(9±9)％与(3±3)％,t=-2.131,P＜0.05];CD8+CD28-T细胞明显降低[(38±15)％与(54±18)％,t=2.975,P＜0.01];CD8+ CD28- ICOS+、C1D4+CD28+和CD4+CD28-T细胞无明显变化（P＞0.05）。②同一RA患者SFMC与PBMC相比,CD4+CD28+ICOS+、CD8+ CD28+T细胞明显升高[(38±18)％与(16±10)％,t=-4.065,P＜0.01;(61±16)％与(41±21)％,t=-2.883,P＜0.01];CD8+ CD28-T细胞明显降低[(39±16)％与(59±21)％,t=2.949,P＜0.01]。③缓解期与活动期RA患者相比,PBMC中CD4+CD28-、CD8+ CD28-、CD28-ICOS+T细胞无明显变化（P＞0.05）。结论 RA患者关节液中CD28-T细胞亚群失衡和ICOS分子表达异常,可能是导致RA关节损伤的重要机制。     

系统性红斑狼疮患者外周血CD4+CD25+T细胞亚群的表达及临床意义

目的研究系统性红斑狼疮(SLE)患者外周血CD4~ 、CD25~ 、CD4~ CD25~ 淋巴细胞亚群的变化及临床意义。方法采用二色荧光抗体标记法,以流式细胞仪对34例SLE患者和18名正常人外周血CD4~ 、CD25~ 、CD4~ CD25~ 淋巴细胞亚群进行了检测,以CD25抗原荧光强度≥10的细胞定义为CD25~(high)细胞,分析其百分率和荧光强度,并结合临床资料进行相关分析。结果活动组SLE患者外周血CD4~ CD25~ 细胞、CD4~ CD25~(high)细胞占总淋巴细胞的百分率[(4．80±1．21)%和(0．25±0．10)%]均低于正常对照组[(8．92±3．21)%和(0．44±0．22)%],亦低于稳定组SLE患者[(11．28±2．09)%和(0．59±0．34)%](P均＜0．05),而稳定组SLE患者与正常对照组差异无统计学意义(P＞0．05)；但CD4~ CD25~ 细胞占CD4~ 细胞的比例在三组之间差异无统计学意义(P均＞0．05)；外周血CD4~ CD25~ 、CD4~ CD25h~(high)细胞数与系统性红斑狼疮疾病活动指数(SLEDAI)积分呈负相关(r=-0．74,P=0．004和r=-0．614,P=0．026),与其他临床指标如补体、抗核抗体(ANA)滴度等无相关性；活动组SLE患者外周血CD4~ 和CD25~ 细胞亦均低于正常对照组[(23±7)vs(34±7)和(7．4±1．8)vs(13．9±3．4),P＜0．05]；SLE患者CD25抗原的荧光强度高于正常对照组(P＜0．05),而CD4抗原的荧光强度差异无统计学意义(P＞0．05)。结论活动性SLE患者外周血CD4~ CD25~ 细胞数是减少的,并与CD4~ 细胞的减少有关,提示在SLE的发病及病情活动中可能起一定作用。     

尖锐湿疣患者外周血Foxp3+CD4+CD25+调节性T细胞的检测及意义

目的 了解尖锐湿疣患者外周血Foxp3+CD4+CD25+调节性T细胞的表达水平,探讨其在尖锐湿疣发生发展机制中的作用.方法 分别收集30例尖锐湿疣患者(复发15例,初发15例)及20例健康者外周抗凝静脉血,分离出外周血单个核细胞.藻红蛋白(PE)标记抗CD4单抗,异硫氰酸荧光素(FITC)标记抗CD25单抗,细胞破膜后PE标记的抗Foxp3单抗行细胞内染色,三色流式细胞术分析Foxp3+CD4+CD25+调节性T细胞比例.组间比较采用ANOVA检验.结果外周血中Foxp3+CD4+CD25+调节性T细胞水平在尖锐湿疣患者组为(3.4±1.0)%,在复发组为(4.7±1.2)%,均显著高于健康对照组的(1.2±0.5)%(P<0.01).外周血Foxp3+CD4+CD25+调节性T细胞水平在初发组为(2.1±1.0)%,高于健康对照组,但差异无统计学意义,而在复发组明显高于初发组(P<0.05).结论 尖锐湿疣患者外周血Foxp3+CD4<"+>CD25+调节性T细胞数量增加,这种细胞免疫功能失调可能与其免疫学发病机制有关.     

初发系统性红斑狼疮患者外周血CD4+调节性T细胞CD73表达

目的 研究CD73在初发活动性系统性红斑狼疮(SLE)患者外周血CD4+调节性T细胞的表达情况,探讨其在SLE发病中的作用.方法 采用流式细胞术检测29例初发未经治疗的活动期SLE患者(SLE组)和22例健康人(健康对照组)外周血CD4+CD25+CD73+T细胞百分率及CD4+CD73+、CD4+CDhi25、CD4+CD25+T细胞中叉头状转录因子3(FOXP3)蛋白表达,同时对CD73表达水平与SLE活动指标进行相关性分析.结果 SLE组患者外周血CD4+ CD25+ CD73+T细胞百分率低于健康对照组[(1.25±1. 32)%vs(2.35±1.09)%,P＜0.01].SLE组和健康正常对照组,CD73在C4+ CDhi25T细胞的表达水平[(29.05±12.53)%、(43.35±10.09)%]高于CD4+ CD25+T细胞[(17.48±6.92)%、(29.98±10.39)%,P＜0.001];FOXP3蛋白在CD4+ CD73+ T细胞[(65.36±14.40)%、(63.80±14.05)%]、CD4+ CDhi25 T细胞的表达水平[(67.30±13.04)%、(56.30±9.21)%]明显高于CD4+ CD25+ T细胞[(45.70±12.74)%、(43.98±5.17)%,P＜0.001],在CD4+ CD73-T细胞几乎不表达,而在CD4+ CD73+ T细胞、CD4+ CDhi25 T细胞中的表达差异无统计学意义(P值均大于0.05).CD73在CD4+ CD25+ T细胞的表达水平与SLE疾病活动指数、ESR、C反应蛋白、抗补体C1q、抗核小体抗体均无相关性(P＞0.05).结论 CD73可作为调节性T细胞新的表面标记,其在调节性T细胞中的异常表达可能参与SLE的发病机制.     

心肌梗死患者CD4~+CD25~+Foxp3~+ T细胞检测及意义

目的探讨心肌梗死患者外周血CD4+CD25+Foxp3+T细胞的水平及意义。方法采用流式细胞分析法,检测20例急性心肌梗死患者(AMI组)、21例陈旧性心肌梗死患者(OMI组)和36例健康体检者(对照组)外周血CD4+CD25+Foxp3+T细胞水平。结果 AMI组、OMI组的CD4+CD25+T细胞/CD4+T细胞比例分别为(7.20±1.96)%和(7.55±1.77)%均低于对照组的(8.81±1.50)%(P0.05);CD4+CD25+Foxp3+T细胞/CD4+T细胞比例AMI组为(1.42±0.38)%和OMI组为(1.46±0.55)%均比对照组(1.75±0.58)%低(P0.05)。结论 CD4+CD25+调节性T细胞比例降低可能打破了外周免疫耐受,参与了心肌梗死患者动脉粥样硬化的发生发展。     

CD4+CD+25 T细胞变化与肺癌的关系

目的 探讨外周血CD4 CD25 T细胞及其所分泌的细胞因子与肺癌的临床相关性.方法 选择68例肺癌患者和30例健康志愿者抽取静脉血,采用流式细胞术检测CD4 CD 25T细胞水平和淋巴细胞亚群,ELISA方法测定TGF-β、IL-10和IFN-γ的水平.结果 肺癌患者外周血CD 4 CD25 T细胞水平明显高于正常对照组(P<0.05),且在肿瘤晚期(Ⅳ期)尤其明显.肺癌患者外周血中TGF-β、IL-10水平高于正常对照组(P<0.05),IFN-γ水平低于正常对照组(P<0.05).结论 肺癌患者外周血CD4 CD25 T细胞水平及其抑制因子的升高与肿瘤免疫功能低下及肺癌的发生密切相关.     

原发性胆汁性肝硬化T淋巴细胞亚群分析

目的 探讨原发性胆汁性肝硬化(PBC)患者的T淋巴细胞亚群及共刺激信号表达的特点及临床意义.方法 以未经治疗的98例PBC患者为研究组,性别、年龄匹配的健康人30名作为对照组.以流式细胞仪技术检测外周血淋巴细胞亚群以及T淋巴细胞表面的共刺激信号CD28.结果 PBC与对照组T细胞亚群差异有统计学意义:PBC组CD4+T淋巴细胞升高,CD8+T淋巴细胞下降,CD4+/CD8+比值上升(P<0.05);CD4+CD28-T细胞和CD8+CD28-T细胞明显增加(P<0.05).结论 PBC存在免疫调节功能的异常,其中CD28的表达明显减少;CD8+CD28-的细胞群可能在PBC中有一定的免疫调节作用.     

肺癌患者外周血CD4+ CD25+调节性T细胞的检测及其临床意义

目的检测肺癌患者外周血CD4 CD2 5调节性T细胞的分布并探讨相关机制。方法流式细胞仪分析46例肺癌患者外周血CD4 CD25 调节性T细胞占CD4 T淋巴细胞的比例;并用ELISA方法检测同标本血中转化生长因子-1(TGF-β1)的浓度。结果46例肺癌患者外周血中CD4 CD2 5调节性T细胞占CD4 T淋巴细胞的比例为(19.1±2.3)%,与对照组(4.1±0.6)%比较差异有显著性(P<0.05)。22例鳞癌、19例腺癌、5例小细胞癌患者外周血中CD4 CD2 5调节性T细胞比例分别为(20.1±0.9)%、(18.8±0.4)%、(19.2±0.4)%,各组间比较差异无显著性(P>0.05);均显著高于对照组(4.1±0.6)%,P<0.05;20例Ⅲ、15例Ⅳ晚期肺癌患者外周血中CD4 CD2 5调节性T细胞比例为(21.4±2.1)%、(20.1±1.3%),均显著高于11例Ⅱ期患者(10.6±1.5)%,P均<0.05。肺癌组外周血清中TGF-β1的水平显著高于对照组,且随着TGF-β1浓度的增加,CD4 CD2 5调节性T细胞比例逐渐增高,两者呈正相关(r=0.0615,P<0.05)。结论肺癌患者外周血中有CD4 CD25 调节性T细胞比例增高,且与分期有关。     

Precommitment of CD4+CD8+ thymocytes to either CD4 or CD8 lineages.

CD4+ and CD8+ mature T cells arise from CD4+CD8+ precursors in the thymus. During this process, cells expressing T-cell receptors (TCRs) reactive with self major histocompatibility complex (MHC) class I or II molecules are positively selected to the CD8 or CD4 lineage, respectively. It is controversial whether lineage commitment of CD4+CD8+ thymocytes is controlled directly by TCR specificity for MHC (instructional model) or, alternatively, by processes that operate independently of TCR specificity (stochastic model). We show here that CD4+CD8+ thymocytes bearing a MHC class I-restricted transgenic TCR can be subject to two alternative developmental fates. One population of CD4+CD8+ cells is positively selected by MHC class I molecules to the CD8 lineage as expected, whereas the other CD4+CD8+ population rearranges endogenous TCR genes and is positively selected by MHC class II molecules to the CD4 lineage. Blocking TCR-MHC class II interactions in vivo does not interfere with the generation of CD4+CD8+ cells expressing endogenous TCRs but does prevent their subsequent maturation to CD4+ cells. These data support a version of the stochastic model in which CD4+CD8+ thymocytes are precommitted to the CD4 or CD8 lineage independently of TCR specificity for MHC and prior to positive selection.     

CD4 engagement by CD1d potentiates activation of CD4+ invariant NKT cells

The CD4 coreceptor is crucial in the activation of major histocompatibility complex (MHC) class II restricted CD4 (+) T lymphocytes by binding the same MHC class as the T-cell receptor (TCR) and by potentiating TCR-dependent signaling. CD4 is also expressed by invariant natural killer T cells (iNKT), which recognize natural and synthetic lipid antigens, such as alpha-galactosyl ceramide (alpha-GalCer), in association with the MHC class I-like CD1d molecule. Human iNKT cells can be divided into 2 major subsets depending on CD4 expression: CD4 (+) iNKT preferentially produce T-helper (Th)0/Th2 cytokines, whereas CD4(-) iNKT cells produce Th1 cytokines after antigenic activation. Cytokines produced by iNKT may have immunomodulatory roles in various physiopathologic contexts, but their mode of regulation by iNKT cells remains ill-defined. Using blocking reagents neutralizing CD4 binding, experimental systems where MHC class II molecules are absent and recombinant alpha-GalCer/CD1d complexes, we show that CD4 potentiates human iNKT cell activation by engaging CD1d molecules. These results indicate that the CD4 coreceptors may contribute to the fine tuning of iNKT cells reactivity.     

CD4-dependent and CD4-independent HIV-2: consequences for neutralization

BACKGROUND: HIV-2 is less pathogenic than HIV-1. In contrast to HIV-1, many isolates of HIV-2, including primary isolates, can infect cells independently of CD4. OBJECTIVE: To compare the sensitivity of CD4-dependent and CD4-independent isolates of HIV-2 to antibody-mediated neutralization. METHODS: The neutralization sensitivity of CD4-dependent and CD4-independent molecular clones of HIV-2 to a panel of HIV-2-positive serum samples was tested. Monoclonal antibodies to various epitopes across the viral envelope were used to determine whether a specific epitope conferred neutralization sensitivity. Neutralization sensitivity of primary isolates of HIV-2 able to infect in the absence of cellular CD4 was also investigated. Antibody binding to sensitive and resistant envelopes was analysed using enzyme-linked immunosorbent assay and flow cytometry. RESULTS: CD4-independent ROD B was highly sensitive to neutralization by HIV-2-positive sera compared with the CD4-dependent isolate ROD A. Induction of ROD A to infect CD4-negative cells by soluble CD4 rendered it equally sensitive to antibody neutralization. Similarly, primary X4, R5 or dual-tropic isolates of HIV-2 were significantly more susceptible to neutralization when utilizing a CD4-independent route of infection. Neutralization sensitivity was not epitope specific but several conformation-dependent antibodies accentuated this phenotype. Antibody binding to monomeric or oligomeric envelope did not correlate with neutralization sensitivity. CONCLUSIONS: HIV-2 isolates utilizing a CD4-independent route of infection are more sensitive to antibody-mediated neutralization. Cellular CD4 may protect HIV-2 from neutralization. This sensitivity to neutralization may, in part, explain the lower virus load and slower progression to disease in HIV-2-infected individuals.     

CXCR4 and CD4 mediate a rapid CD95-independent cell death in CD4+ T cells

AIDS is characterized by a progressive decrease of CD4⁺ helper T lymphocytes. Destruction of these cells may involve programmed cell death, apoptosis. It has previously been reported that apoptosis can be induced even in noninfected cells by HIV-1 gp120 and anti-gp120 antibodies. HIV-1 gp120 binds to T cells via CD4 and the chemokine coreceptor CXCR4 (fusin/LESTR). Therefore, we investigated whether CD4 and CXCR4 mediate gp120-induced apoptosis. We used human peripheral blood lymphocytes, malignant T cells, and CD4/CXCR4 transfectants, and found cell death induced by both cell surface receptors, CD4 and CXCR4. The induced cell death was rapid, independent of known caspases, and lacking oligonucleosomal DNA fragmentation. In addition, the death signals were not propagated via p56^lck and G_iα. However, the cells showed chromatin condensation, morphological shrinkage, membrane inversion, and reduced mitochondrial transmembrane potential indicative of apoptosis. Significantly, apoptosis was exclusively observed in CD4⁺ but not in CD8⁺ T cells, and apoptosis triggered via CXCR4 was inhibited by stromal cell-derived factor-1, the natural CXCR4 ligand. Thus, this mechanism of apoptosis might contribute to T cell depletion in AIDS and might have major implications for therapeutic intervention.     

Signaling through CD43 regulates CD4 T-cell trafficking

The mucin-like protein CD43 is excluded from the immune synapse, and regulates T-cell proliferation as well as T-cell migration. While the CD43 cytoplasmic domain is necessary for regulation of T-cell activation and proliferation, the mechanism via which CD43 regulates trafficking is not well defined. To investigate whether CD43 phosphorylation regulates its function in T cells, we used tandem mass spectrometry and identified Ser76 in murine CD43 as a previously unidentified site of basal phosphorylation. Interestingly, mutation of this single serine to alanine greatly diminishes T-cell trafficking to the lymph node, while CD43 exclusion and CD43-mediated regulation of T-cell proliferation remain intact. Furthermore, the CD43 extracellular domain was also required for T-cell trafficking, providing a hitherto unknown function for the extracellular domain, and suggesting that the extracellular domain may be required to transduce signals via the cytoplasmic domain. These data reveal a novel mechanism by which CD43 regulates T-cell function, and suggest that CD43 functions as a signaling molecule, sensing extracellular cues and transducing intracellular signals that modulate T-cell function.     

Naive CD4 T cells inhibit CD28-costimulated R5 HIV replication in memory CD4 T cells

Stimulation with antibodies to CD3 and CD28 coimmobilized on beads can be used to significantly expand T cells ex vivo. With CD4 T cells from HIV-infected patients, this expansion usually is accompanied by complete suppression of viral replication, presumed to be caused by down-regulation of the viral coreceptor CCR5 and up-regulation of CCR5 ligands. Here we show that this suppression occurs in total CD4 T cells acutely infected with R5 HIV, but not in purified CD62L(-) memory CD4 T cells. The lack of complete suppression in these memory cells, typically comprising 10-40% of total CD4 T cells, occurs despite high levels of CCR5 ligand secretion and down-regulation of CCR5. Significantly, adding back naive or CD62L(+) memory CD4 T cells inhibits the viral replication in the CD62L(-) cells, with the naive cells capable of completely repressing the virus. Although this inhibition was previously thought to be specific to bead-bound anti-CD3/CD28 stimulation, we show that the same suppression is obtained with sufficiently strong anti-CD3/B7.1 stimulation. Our results show that inhibitory mechanisms, expressed predominantly by strongly stimulated naive CD4 T cells and mediated independently of CCR5-binding chemokines, play a role in the inhibition of R5 HIV replication in CD4 T cells upon CD28 costimulation.