Combined TCRG and TCRA TREC analysis reveals increased peripheral T-lymphocyte but constant intra-thymic proliferative history upon ageing

T-cell receptor (TCR) repertoire diversity, thymic output, clonal size and peripheral T-lymphocyte numbers largely depend on intra-thymic and post-thymic T-lymphocyte proliferation. However, quantitative insight into thymocyte and T-lymphocyte proliferation is still lacking. We developed a new TCRG-based TCR excision circle (TREC) assay, the Vγ-Jγ TREC assay, which we used together with an adjusted δREC-ψJα TREC assay to quantify the proliferative history of human thymocyte and T-lymphocyte subpopulations from children and adults. This revealed that thymocytes undergo ～6–8 intra-thymic cell divisions from the double negative (DN) 3 developmental stage onwards, which appeared independent of age. Thus thymocyte proliferation after the DN3 developmental stages is stable and therefore not contributing to the reduced thymic output upon ageing. Cord blood naive T lymphocytes had already undergone ～2–3 post-thymic cell divisions, which increased to ～6–7 cell divisions in naive T lymphocytes of middle-aged adults, indicating the importance of homeostatic naive T-lymphocyte proliferation from a young age onwards in the maintenance of peripheral T-lymphocyte numbers. In conclusion, our data provide quantitative insight into the proliferative history of thymocyte and T-lymphocyte subpopulations and alterations herein upon ageing. This novel TREC assay approach could prove valuable in immune status monitoring in a variety of conditions.     

SEB活化的人外周血T细胞CD25,CD69的表达

本文用超抗原葡萄球菌肠毒素B(SEB)诱导外周血淋巴细胞增殖。结果显示出微量超抗原能诱导外周血淋巴细胞的增殖,大量的增殖反应发生在SEB刺激后的第5天,增殖的细胞是CD4~+T细胞,它们由刺激前的27％增加到42％。外周血活化的T细胞不依赖外源性IL-2:大量内源性IL-2的存在抑制T细胞的增殖反应。伴随CD4~+T细胞的增殖,CD25和CD69分子表达明显增加。提示SEB能改变外周血T细胞表面的分子表达。     

Identification of canine lymphocyte populations by immunofluorescence surface marker analysis

A T-cell-specific rabbit anti-dog thymocyte antiserum was prepared and used in an indirect fluorescent antibody technique to identify T lymphocytes. The antiserum was rendered specific by absorptions with normal dog red blood cells, lyophilized serum, and bone marrow cells. By the indirect immunofluorescence assay, 73.6 +/- 1.2 (SEM)% of the peripheral blood lymphocytes were identified as T lymphocytes. By direct immunofluorescence assay of surface membrane immunoglobulin-positive lymphocytes, 18.2 +/- 0.8% of the peripheral blood lymphocytes were identified as B lymphocytes. The two assays used in conjunction can thus identify over 90% of the peripheral blood lymphocytes as either T or B lymphocytes, with the remaining 8.2 +/- 1.0% as null cells.     

淫羊藿多糖致小鼠胸腺缩小的免疫药理机理研究

淫羊藿多糖(EPS)刺激外周T 细胞功能的同时,引起胸腺缩小。我们发现EFS10～50mg/kg 范围内.胸腺缩小伴随着胸腺内L3T4~+和Lyt2~+细胞数减少,对有丝分裂原的刺激反应降低;但此时胸腺细胞增殖和产生IL-2能力提高。单次大剂量(100mg/kg)皮下注射.能够引起小鼠胸腺细胞释放增加,P<0.01。由此我们认为,EPS 促进胸腺释放成熟细胞是其导致胸腺缩小的机理之一,也是其增强机体细胞免疫功能的重要机制。     

Resistance of Staphylococcal enterotoxin B- induced proliferation and apoptosis to the effects of dexamethasone in mouse lymphocyte cultures.

Staphylococcal enterotoxin B (SEB) is a superantigen causing lymphocyte proliferation and apoptosis. Glucocorticoids are immunosuppressants and are released immediately following SEB intoxication in mice. Whether glucocorticoids affect lymphocyte proliferation and apoptosis in SEB-intoxicated mice is still unknown. To study this question, we examined the effects of dexamethasone (DEX), a synthetic glucocorticoid, on SEB-stimulated lymphocyte cultures from mouse thymus and peripheral lymphoid tissues (PLT). SEB, as well as concanavalin A (Con A), induced lymphocyte proliferation which peaked on day 4 and declined significantly on day 7. As expected, in Con A-stimulated cultures, DEX completely suppressed the proliferation of lymphocytes from both the thymus and PLT. However, in SEB-stimulated cultures, while DEX completely suppressed thymocyte proliferation, it did not suppress PLT cell proliferation even at a high concentration of 10(-7) M. The proliferating cells were Vbeta8(+) T cells of both the CD4(+) and CD8(+) subsets. DEX caused apoptosis. SEB also caused apoptosis, which was manifested by a maximal DNA subdiploidy on day 4 and by a maximal DNA fragmentation on day 7. Both events appeared not to be affected by DEX. The failure of DEX to affect the proliferation and apoptosis was consistent with high levels of cytokines (IL-1alpha, IL-2, IL-4, IL-6 and IFN-gamma) produced in the SEB-stimulated cultures, suggesting that the cytokines act in concert to circumvent the effects of DEX.     

Flow cytometric analysis of genetic damage, effect on cell cycle progression, and apoptosis by thiophanate-methyl in human lymphocytes

Flow cytometric technique was used to study the effects of the fungicide Thiophanate-methyl on cell proliferation, micronucleus induction, and apoptosis in human peripheral blood lymphocytes treated in vitro. In particular, a combined approach of flow cytometry and fluorescence in situ hybridization (FISH) with a pancentromeric alpha-satellite probe was used to evaluate the mechanism of micronucleus induction by Thiophanate-methyl. Flow sorted micronuclei (MN) induced in human lymphocytes by Thiophanate-methyl were analyzed by FISH and the results were compared with results from FISH analysis on MN in binucleated cells. It could be shown that most MN induced by Thiophanate-methyl did not reveal any centromeric signal, thus demonstrating clastogenic action of this fungicide. Moreover, it was found that as a function of the concentration of Thiophanate-methyl, cellular proliferation was delayed and the frequency of apoptotic cells was increased.     

JNK,but not MAPK,activation is associated with Fas-mediated apoptosis in human T cells

Fas is a cell surface molecule that is expressed on a wide array of cell types and triggers apoptosis. While in most situations Fas ligation activates programmed cell death, on resting T lymphocytes it can co-stimulate proliferation with the T cell receptor (TCR)/CD3 complex. This incongruity suggests that Fas may elicit signaling events that overlap with those used by proliferation cues. We observe that in the human T cell line Jurkat and in human peripheral blood lymphocytes, Fas stimulation does not signal by the Ras/Raf-1/mitogen-activated protein kinase (MAPK) pathway or by increased intracellular calcium. Rather, Fas ligation strongly activates Jun kinase (JNK). This activity, as well as Fas-induced apoptosis, is blocked by increased levels of cAMP. The balance between proliferation and apoptosis by Fas triggering of T lymphocytes may therefore reflect a signaling ratio between TCR activation of the Ras/Raf-1/MAPK pathway versus JNK activation by Fas.     

Effect of interleukins on the proliferation and survival of B cell chronic lymphocytic leukaemia cells.

AIMS--To investigate the effects of interleukin (IL) 1, 2, 4, and 5 on the proliferation and survival of peripheral blood B cells from patients with B chronic lymphocytic leukaemia (B-CLL) and compare them with the effects on normal peripheral blood B cells. METHODS--The proliferation and survival of pokeweed mitogen (PWM) activated B cells from B-CLL (n = 12) and normal peripheral blood (n = 5) were studied in vitro in response to IL-1, IL-2 IL-4, and IL-5. Survival of cells in cultures with or without added interleukins was studied by microscopic examination of cells and DNA agarose gel electrophoresis. RESULTS--Proliferation was observed in both B-CLL and normal peripheral blood cells on culture with IL-2 alone and also in some, but not all, B-CLL and normal peripheral blood cells with IL-1 and IL-4. However, there was greater variability in B-CLL cell responses than in normal peripheral blood cells. Il-5 did not affect normal peripheral blood cell proliferation but it increased proliferation in two B-CLL cases. Synergistic effects of these cytokines were not detected. IL-4 inhibited normal peripheral blood and B-CLL cell proliferation after the addition of IL-2. Inhibition of B-CLL cell responses to IL-2 was also observed with IL-5 and Il-1. Survival of B-CLL cells in cultures was enhanced with IL-4 not by an increase in proliferation but by reduced apoptosis. No such effect was seen in normal peripheral blood cells. IL-2 had a less noticeable antiapoptotic effect; IL-5 enhanced apoptosis in B-CLL cells. CONCLUSIONS--B-CLL and normal peripheral blood cells proliferated equally well in response to IL-2. IL-4 had a much lower effect on B-CLL cell proliferation, but had noticeable antiapoptotic activity. IL-5 enhanced cell death by apoptosis.     

Lymphocyte Proliferative Response to Viral Antigen in Pigs Infected with Transmissible Gastroenteritis Virus

Development and sequence of lymphocytes reactive to viral antigen in Peyer's patches, mesenteric lymph nodes, spleen, and peripheral blood of pigs orally inoculated with transmissible gastroenteritis virus were investigated by a lymphocyte proliferative assay. Lymphocytes reactive to the viral antigen were first detected in all the tissues of pigs tested on postinoculation day 7. Thereafter, they increased in proliferative reactivity and reached a maximal amount on postinoculation days 10 to 14. Antigen-reactive cells were persistently demonstrated in Peyer's patches and mesenteric lymph nodes for at least 110 days after inoculation, although lymphocytes decreased a little in reactivity to the viral antigen with the lapse of time. On the other hand, splenic and peripheral blood cells were found to have only transient proliferative reactivity. No antigen-reactive cells were detected in spleen or peripheral blood after postinoculation days 20 to 30. Lymphocytes decreased remarkably in reactivity to the viral antigen and phytohemagglutinin when treated with anti-porcine thymocyte serum and complement. Their reactivity to lipopolysaccharides was hardly affected by the treatment. Cells harvested on postinoculation days 45 to 60, however, responded a little to the viral antigen even after they were treated with anti-porcine thymocyte serum and complement. Lymphocytes reactive to the viral antigen and phytohemagglutinin belonged mainly to the erythrocyte rosette-forming cell fraction, whereas those reactive to lipopolysaccharides were mostly found in the rosette-nonforming cell fraction.     

骨髓间充质干细胞对异体外周血B淋巴细胞的免疫调节作用

目的 探讨骨髓间充质干细胞(mesenchymal stem cells, MSC)在体外对异体外周血B淋巴细胞的免疫调节作用.方法 用密度梯度离心法从骨髓中分离、培养MSC,从外周血中分离单个核细胞,L-亮氨酸甲酯去除单核细胞,以2-氨乙基硫脲溴化物(AET)处理绵羊红细胞(SRBC)的花环形成法,去除T淋巴细胞获得纯化的B淋巴细胞.用羊抗人IgM单克隆抗体(anti-IgM)刺激与或未与MSC或其培养上清共培养3d的B淋巴细胞,应用MTT法测8淋巴细胞的增殖,ELISA法测培养上清中免疫球蛋白IgG、lgM的产生,应用流式细胞术分别检测与MSC共培养24、48h后B淋巴细胞的凋亡.结果 MSC及其培养上清抑制由anti-IgM诱导的B淋巴细胞的增殖和分泌IgG、IgM,且随着MSC细胞数量及其培养上清浓度的增加,这种抑制越明显.流式细胞术结果显示,与MSC共培养不同时间的B淋巴细胞的凋亡变化无统计学意义,MSC抑制B淋巴细胞的增殖存在暂时性和可逆性.结论 MSC对异体外周血8淋巴细胞存在免疫调节作用,并且这种调控机制是复杂的,不仅与MSC细胞数量有关,还与细胞间的相互作用和MSC分泌的细胞因子有关.     

PMA协同IM刺激新生儿脐血淋巴细胞增殖及钙离子浓度的变化

本文比较新生儿脐带血和成人外周血淋巴细胞对抗CD3单克隆抗体、PMA和IM刺激的增殖反应及细胞内钙离子浓度的变化 ,了解新生儿出生时淋巴细胞功能缺陷可能的环节。结果表明应用抗CD3单克隆抗体或PMA协同IM刺激 ,脐带血淋巴细胞增殖反应及细胞内钙离子浓度明显增强 ,PMA协同IM刺激 ,脐带血淋巴细胞的增殖反应更接近于成人。由于PMA协同IM刺激可部分改善新生儿脐带血淋巴细胞增殖反应的缺陷 ,提示细胞信号传导的上游缺陷可能为新生儿出生时淋巴细胞功能低下的原因之一。     

Apoptosis of T lymphocytes isolated from peripheral blood of patients with acute exacerbation of chronic obstructive pulmonary disease

Purpose

Chronic obstructive pulmonary disease (COPD) is characterized by chronic inflammation of the airways and progressive destruction of lung parenchyma. Apoptosis is critical for the maintenance of normal tissue homeostasis and is in equilibrium with proliferation and differentiation. This study was undertaken to investigate relationship between apoptosis of peripheral blood lymphocytes during exacerbation of COPD and inflammatory response that characterizes this condition.

Materials and Methods

Seventeen patients with COPD exacerbation, 21 stable COPD, and 12 control subjects were included. T lymphocytes were isolated from peripheral blood using MACS. Apoptosis of T lymphocytes was assessed with FACS using annexin V and 7-aminoactinomycin. Serum levels of interleukin (IL)-6, IL-8 and tumor necrosis factor (TNF)-α were determined by an immunoassay technique.

Results

There was significantly increased percentage of apoptotic lymphocytes, CD 4⁺, and CD 8⁺ T cells in the peripheral blood of patients with exacerbation of COPD compared with stable COPD. Serum levels of IL-6, IL-8, and TNF-α were significantly increased in patients with exacerbation of COPD compared with stable COPD. Only TNF-α presented a positive correlation with apoptotic lymphocytes in patients with exacerbation of COPD.

Conclusion

Increased apoptotic lymphocytes may be associated with upregulation of TNF-α in the peripheral blood of patients with acute exacerbation of COPD.     

PHA-induced cell proliferation rescues human peripheral blood lymphocytes from X-ray-induced apoptosis

Human peripheral blood G(0) lymphocytes were X-irradiated and allowed to recover for different periods both in the presence and absence of phytohemagglutinin (PHA). For each experimental condition the induction of apoptosis was investigated by nuclear morphology and formation of both DNA laddering and high molecular weight DNA fragments by pulsed field gel electrophoresis. The results showed that PHA cell growth stimulation could rescue peripheral blood lymphocytes (PBLs) from X-ray-induced apoptotic cell death. Instead, most X-irradiated lymphocytes held in G(0) phase, once they were committed to apoptosis, inexorably executed the process. These data indicate that the proliferative status of PBLs can influence apoptotic cell death: PHA-stimulated PBLs appear to be more radioresistant as a result of a less efficient apoptotic process. Therefore, in current tests for mutagenicity or cytotoxicity and in biodosimetrical studies the possible role of apoptosis has to be considered.     

APO—1／Fas及其配体介导超抗原SEB诱导的淋巴细胞凋亡

为了探讨超抗原诱导的淋巴细胞凋亡机制．本实验采用超抗原金黄色葡萄球菌肠毒素B（SEB）处理人外周血单个核细胞,采用流式细胞术检测细胞DNA断裂的百分率;同时动态观察了细胞表面APO-1、FasL的表达及细胞内Bcl－2蛋白的表达。结果表明,SEB不但可引起人外周血淋巴细胞凋亡,而且可诱导淋巴细胞表达APO-1和FasL。细胞凋亡的百分率与细胞表面APO-1和FasL的表达呈正相关（r＝0．71,r＝0．98）,与细胞内Bcl－2表达呈负相关（r＝－0．72）。由此可见,APO－1／Fas及其配体参与了超抗原SEB诱导的淋巴细胞凋亡。     

Effect of protein kinase C on proliferation and apoptosis of T lymphocytes in idiopathic thrombocytopenic purpura children

It is well-documented that T lymphocyte proliferation and apoptosis are abnormal in idiopathic thrombocytopenic purpura （ITP） children. However, the underlying regulation mechanisms especially in terms of signal transduction remain unknown. In this paper, we reported the changes of protein kinase C （PKC） activity in peripheral blood T lymphocytes and the effect of PKC on T lymphocyte proliferation and apoptosis. We demonstrated that in ITP children, the activator （PMA） and inhibitor （H-7） of PKC affected on T lymphocyte proliferation and apoptosis dramatically, but they altered little in healthy children. PKC activity was significantly enhanced in ITP children together with an increased expression of FasL on CD3^＋ T, CD4^＋T and CD8^＋T cells, resulting in a positive correlation between PKC activity and the expression of FasL on T cells. While the PKC activity and the platelet count were negatively correlated. Taken together, our findings suggest that the PKC activation may enhance T lymphocytes activity, suppress T cell apoptosis and be involve in thrombocytes damage as a mechanism related to immune pathogenesis of ITP. Cellular ＆ Molecular Immunology. 2005; 2（3）： 197-203.     

Enhanced glucocorticoid receptor signaling in T cells impacts thymocyte apoptosis and adaptive immune responses

To study the effect of enhanced glucocorticoid signaling on T cells, we generated transgenic rats overexpressing a mutant glucocorticoid receptor with increased ligand affinity in the thymus. We found that this caused massive thymocyte apoptosis at physiological hormone levels, which could be reversed by adrenalectomy. Due to homeostatic proliferation, a considerable number of mature T lymphocytes accumulated in the periphery, responding normally to costimulation but exhibiting a perturbed T-cell repertoire. Furthermore, the transgenic rats showed increased resistance to experimental autoimmune encephalomyelitis, which manifests in a delayed onset and milder disease course, impaired leukocyte infiltration into the central nervous system and a distinct cytokine profile. In contrast, the ability of the transgenic rats to mount an allergic airway response to ovalbumin was not compromised, although isotype switching of antigen-specific immunoglobulins was altered. Collectively, our findings suggest that endogenous glucocorticoids impact T-cell development and favor the selection of Th2- over Th1-dominated adaptive immune responses.     

Advanced age in horses affects divisional history of T cells and inflammatory cytokine production

A number of model systems have been employed to investigate age-associated changes in immune function. The purpose of the current study was to characterize senescent T cells and to investigate the inflamm-aging phenomenon both in vitro and in vivo using the old horse as a model. We examined whether decreased T cell proliferation induced by Con A is caused by increased apoptosis. We also utilized intracellular CFSE to analyze changes within each round of cell proliferation, in particular cytokine production. Intracellular staining with flow cytometry, RT-PCR, and ELISA were used to measure pro-inflammatory cytokines both in vitro and in vivo. While lymphocytes from old horses exhibit decreased proliferation, this is not the result of increased apoptosis. Instead, a larger percentage of the T cells remain in the parent generation and produce significant amounts of IFNgamma. Likewise, old horses have increased frequency of CD8-IFNgamma+ T cells and TNFalpha producing cells. We also show that old horses have elevated levels of IL-1beta, IL-15, IL-18 and TNFalpha gene expression in peripheral blood and significant levels of TNFalpha protein in serum, all characteristics of inflamm-aging.     

Elevated apoptosis of peripheral T lymphocytes in diabetic BB rats

Thymocytes and peripheral lymphocytes of BioBreeding (BB) diabetes-prone (BBDP) and diabetes-resistant (BBDR) rat were analysed by fluorescence-activated cell sorter (FACS). The number of CD4- CD8-, CD4+ CD8-, CD4- CD8+ and CD4+ CD8+ subsets was not different between BBDP and BBDR rat thymocytes, whereas spleen and lymph nodes in BBDP rats undergo severe T-cell lymphopenia. Notably, mature CD4- CD8+ [T-cell receptor (TCR)-alphabeta+ and CD5+] cells are certainly present in the BBDP rat thymus, unlike some previous reports, suggesting that the differentiation of CD4- CD8+ from CD4+ CD8+ cells occurs normally in the BBDP rat thymus. As a cause of peripheral T-cell lymphopenia we suspected apoptosis of recent thymic emigrants. By FACS analysis with fluorescein isothiocyanate-labelled annexin V, elevated apoptosis was evident in BBDP rat peripheral lymphocytes. Furthermore, terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labelling (TUNEL) staining in BBDP rat splenic sections revealed that a number of TUNEL-positive cells were observed in the T-lymphocyte-rich area. From these results, we postulate that an abnormally elevated apoptosis of peripheral T lymphocytes, but not impaired thymocyte differentiation, is a cause of the peripheral T-cell lymphopenia in BBDP rats.     

SLE患者淋巴细胞凋亡和p53蛋白表达的相关性研究

研究SLE患者外周血淋巴细胞在体外培养下细胞凋亡和p5 3蛋白表达与SLE疾病活动相关性。AnnexinV联合PI染色定量法及免疫荧光染色法 ,分析了 4 4例SLE患者和 30例正常人外周血淋巴细胞在体外培养后凋亡发生率 ,凋亡相关基因p5 3蛋白的表达以及淋巴细胞凋亡发生与疾病活动的相关性。在体外培养作用下 ,活动期SLE患者淋巴细胞凋亡发生率较正常人显著增高 (P <0 0 1 ) ,而静止期则明显升高 (P <0 0 5 ) ,疾病活动指数与体外淋巴细胞凋亡率呈正相关 (P <0 0 1 )。p5 3蛋白表达在活动期SLE患者较正常人显著性下降 (P <0 0 1 ) ,静止期明显降低 (P <0 0 5 )。p5 3蛋白的表达与疾病活动指数SLEDAI,抗dsDNA抗体和C3补体之间有明显的相关性 (P <0 0 1 )。SLE患者外周淋巴细胞在体外培养凋亡率较正常人显著增高 ,表明SLE存在体内凋亡或凋亡相关性免疫机制失调