肿瘤抗原诱导的骨髓基质细胞活化后凋亡

目的　活化后凋亡（ａｃｔｉｖａｔｉｏｎｉｎｄｕｃｅｄ ａｐｏｐｔｏｓｉｓ） 被认为是免疫应答负向调控（ｄｏｗｎｒｅｇｕｌａｔｉｏｎ） 的一种重要方式,抗原提呈细胞在完成了抗原提呈功能后是否也经历一个自身活化后凋亡的过程,目前尚无定论。方法　以巨噬细胞型骨髓基质细胞（ｍａｃｒｏｐｈａｇｅ ｌｉｋｅ ｓｔｒｏｍａｌ ｃｅｌｌｓ） 为模型,探讨抗原提呈细胞是否具有自身活化后凋亡的现象。结果　经 Ｇ Ｍ Ｃ Ｓ Ｆ 诱导的 Ｂ Ｍ Ｓ Ｃ 高表达多种膜表面分子,包括 Ｍ Ｈ ＣⅠ、 Ｍ Ｈ ＣⅡ、 Ｂ７２ 、 Ｖ Ｃ Ａ Ｍ１ 、 Ｃ Ｄ１４ 等,显著表达巨噬细胞的标志 Ｆ４／８０ 和树突状细胞的标志 Ｎ Ｌ Ｄ Ｃ１４５ ;对同种异体淋巴细胞的促增殖能力显著增强,表明 Ｂ Ｍ Ｓ Ｃ 具有抗原提呈细胞的分子和细胞基础与功能活化特征。进一步研究发现, Ｂ Ｍ Ｓ Ｃ 经 Ｆ Ｂ Ｌ３ 肿瘤抗原刺激后１８ 小时,上述多种免疫分子表达明显下调,而 Ｆａｓ Ｌ 分子明显升高,透射电镜显示其具有明显的凋亡特征。结论　骨髓基质细胞经肿瘤抗原诱导后存在凋亡现象,其具体机制和免疫调节意义有待进一步探讨。     

糖皮质激素受体β对糖皮质激素受体α功能的影响及其意义

目的 :通过研究糖皮质激素受体 β对糖皮质激素受体α功能的影响 ,探讨糖皮质激素受体 β可能存在的生物学意义。方法 :( 1 )用瞬时转染技术将ＧＲβ和报告基因ｃａｔ共转染ＨＯＳ - 860 3细胞 ,激素处理后 ,研究ＧＲβ对糖皮质激素诱导ＧＲα外源性靶基因ｃａｔ表达的影响 ;( 2 )ＧＲβ真核表达载体的构建及ＧＲβ在ＨＯＳ - 860 3细胞中的稳定过度表达 ;( 3)用定量ＲＴ -ＰＣＲ和Ｗｅｓｔｅｒｎ印迹法检测糖皮质激素对ＨＯＳ -860 3细胞ｐ2 1表达的诱导及ＧＲβ的稳定表达对ＧＲα内源性靶基因ｐ2 1表达的影响 ;( 4 )用ＭＰＴ法检测ＧＲβ…     

LIGHT 一个新的非CD28依赖的T细胞共刺激分子

ＬＩＧＨＴ(ｆｏｒｈｏｍｏｌｏｇｏｕｓｔｏｌｙｍｐｈｏｔｏｘｉｎｓ ,ｅｘｈｉｂｉｔｓｉｎ ｄｕｃｉｂｌｅｅｘｐｒｅｓｓｉｏｎ ,ａｎｄｃｏｍｐｅｔｅｓｗｉｔｈＨＳＶｇｌｙｃｏｐｒｏｔｅｉｎＤｆｏｒＨＶＥＭ ,ａｒｅｃｅｐｔｏｒｅｘｐｒｅｓｓｅｄｂｙＴｌｙｍｐｈｏｃｙｔｅｓ) 〔1〕是1998年发现的ＴＮＦ超家族成员 ,又称为ＨＶＥＭ Ｌ(ｈｅｒｐｅｓｖｉｒｕｓｅｎｔｒｙｍｅｄｉａｔｏｒ ｌｉｇａｎｄ) 〔2〕 是肿瘤坏死因子超家族的第 14个成员 (ＴＮＦＳＦ14)。由于ＬＩＧＨＴ同时具有诱导肿瘤细胞凋亡和共刺激Ｔ细胞活化的…     

P33^ING1基因生物学功能及研究进展

Ｇａｒｋａｖｔｓｅｖ等〔1〕采用ｃＤＮＡ消减杂交方法 (ｓｕｂｓｔｒａｃｔｉｖｅｈｙｂｒｉｄｉｚａｔｉｏｎ)建立了一种从富含所需序列的ｃＤＮＡ文库中构建较简便ＧＳＥｓ(ｇｅｎｅｔｉｃｓｕｐｐｒｅｓｓｏｒｅｌｅｍｅｎｔｓ)文库的方法 ,并结合体内选择技术 (ｉｎｖｉｖｏｓｅｌｅｃｔｉｏｎａｓｓａｙ) ,成功地克隆了一个新的肿瘤抑制基因 ,命名为ＩＮＧ1(ｉｎｈｉｂｉｔｏｒｏｆｇｒｏｗｔｈ)。研究发现 ,Ｐ33ＩＮＧ1的过表达可有效抑制细胞生长 ,促进无生长因子条件下的细胞凋亡 ,在抑制细胞生长过程中 ,Ｐ33ＩＮＧ1与ｐ5 3相互…     

丙型肝炎病毒核心区蛋白对HepG2细胞凋亡的影响

已有越来越多的证据表明肝细胞和外周血淋巴细胞凋亡在丙型肝炎的发生和慢性化过程中起着重要作用。ＨＣＶ核心区 (ＨＣＶ Ｃ)具有较强的免疫调节功能 ,但ＨＣＶ Ｃ蛋白究竟是促进细胞凋亡还是抑制细胞凋亡目前还有争论。目前尚未见有关ＴＲＡＩＬ(ＴＮＦｒｅｌａｔｅｄａｐｏｐｔｏｓｉｓｉｎｄｕｃｉｎｇｌｉｇａｎｄ)所介导细胞凋亡在丙型肝炎致病过程中所起作用的研究报道。本实验主要研究ＨＣＶ Ｃ蛋白对ＨｅｐＧ2细胞凋亡的影响。通过基因重组技术构建包括ＨＣＶ Ｃ的重组真核表达质粒 ,将重组真核表达质粒经脂质体介导稳定转染肝癌细…     

病毒致细胞程序性死亡分子机制的研究

细胞凋亡 (Ａｐｏｐｔｏｓｉｓ)又称为细胞程序性死亡 ,是细胞自主死亡的过程 ,在组织发生、免疫系统克隆选择、机体内环境稳定等诸多方面有着广泛的生物学意义[1] ,在某些疾病 ,如肿瘤、艾滋病等发病机制中也具有重要意义。参与细胞凋亡基因很多 ,主要有ｂｃ1 2、ｃ ｍｙｃ、ｐ5 3、ｃｅｄ 3、Ｆａｓ/Ａｐｏ 1等。近年研究发现 ,病毒感染是调节细胞凋亡的重要因素 ,病毒感染后不仅可通过自身基因的表达激活或抑制细胞凋亡的发生 ,也可与细胞凋亡调节基因一起共同参与凋亡的调控[2 ] 。下面拟就细胞凋亡的主要相关基因、病毒诱导或抑制细胞…     

TGFβ1 诱导 THP-1 细胞分化为巨噬细胞时原癌基因表达的变化

对重组转化生长因子β１（ＴＧＦ－β１）诱导前单核白血病细胞系ＴＨＰ－１细胞向巨噬细胞分化过程中核内原癌基因表达的动态变化进行了研究。结果发现，在诱导分化过程中不同的原癌基因表达变化不仅具有时序性，调节方式也呈多样性。ｃ－ｆｏｓ、ｃ－ｊｕｎｍＲＮＡ表达变化在时间上有一致性，诱导分化早期（２４小时）贴壁细胞的表达量明显增加，延长ｒｈＴＧＰ－β１作用时间至４８～７２小时时，这种上调作用消失，回复到对照组ＴＨＰ－１细胞原有的或低于原有的表达水平。ｃ－ｍｙｃ在细胞分化过程中表达逐渐降低，作用７２小时时表达量不足对照组细胞的１０％。而ｃ－ｓｉｓ在ｒｈＴＧＰ－β１作用７２小时内未发现其表达被调节。提示ｃ－ｆｏｓ、ｃ－ｊｕｎ基因在分化早期的表达上调，以及ｃ－ｍｙｃ基因在分化中期的表达被强烈抑制可能分别在分化进程中发挥重要作用。     

一种检测肿瘤细胞凋亡的新方法

细胞凋亡 (ａｐｏｐｔｏｓｉｓ)检测方法有多种 ,但大多操作复杂且需贵重试剂或仪器。我们根据ＭＴＴ试验及台盼蓝试验的原理 ,设计了一种由二者计算细胞凋亡率的简单方法 ,并以此方法分析了白血病细胞株ＨＬ - 60受抗癌药物ＶＰ - 1 6诱导时的凋亡情况。材　料　和　方　法一、细胞培养ＨＬ - 60细胞株 (本院血液病研究室提供 ) ,常规 1 640 (Ｇｂｉｃｏ)培养 ,隔天换液 ,取对数生长期的细胞实验。二、细胞处理调整细胞浓度至 1 0 9/Ｌ ,加入ＶＰ - 1 6(Ｓｉｇｍａ)至所需浓度 1 2ｈ后收获细胞备用 ,药物浓度依次为 0、5、1 0、2 0、40ｍｇ…     

乙型流感病毒诱导HeLa细胞凋亡并伴随P16蛋白高效表达

近年的研究发现 ,甲、乙、丙型流感病毒感染宿主细胞时均可不同程度地诱导细胞凋亡 ,细胞凋亡是流感病毒杀死宿主细胞的主要方式。目前 ,甲型流感病毒诱导宿主细胞凋亡基因的调控及蛋白表达的研究结果已有报道 ,而乙、丙型流感病毒诱导细胞凋亡调节机制的结果尚未见报道。本文以乙型流感病毒 (Ｂ/沪防 93 1株 )感染ＨｅＬａ细胞 ,通过Ｈｏｅｃｈｓｔ 332 5 8荧光染色、琼脂糖凝胶电泳分析检测细胞凋亡 ,并用免疫组化技术测定Ｐ16基因蛋白表达 ,以ＭＰＩＡＳ 5 0 0计算机多媒体图象分析系统作蛋白表达图象分析 ,用阳性染色Ａ值 (吸光度 ,原为…     

p53,Bcl—2,Caspases在一氧化氮诱导凋亡的信号传递机制中作用的 …

一氧化氮可以诱导多种细胞产生凋亡,但其机制尚未阐明。近年来的研究发现,ＮＯ诱导细胞凋亡过程中,抑癌基因Ｐ５３表达增加、原癌基因Ｂｃｌ－２表达下降,以及ｃａｓｐａｓｅ－３半胱氨酸蛋白酶活性增强。本文对这三者及一些相关因素之间的相互联系简要介绍。     

Virulent influenza A viruses induce apoptosis in chickens

Virulent avian influenza A viruses produce lethal disease in chickens. Since cell death can be caused by either necrosis or apoptosis, we investigated the types of cell death that occur in natural hosts, chickens, infected with virulent avian viruses. Using biochemical methods, we demonstrate that virulent avian influenza viruses induce apoptosis of vascular endothelial cells in liver, kidney, and brain. Viral antigens were also detected in these organs, suggesting that viral replication induces apoptosis in infected chickens. These results indicate that apoptosis does occur in virulent avian influenza virus infection in a natural host, and may contribute to the lethality of the virus.     

Natural and induced apoptosis during lymphocyte development in the axolotl.

Lymphocytes apoptosis was characterized in a urodele amphibian, the axolotl, by morphology using electron microscopy and by flow cytometry after propidium iodide staining, as well as by biochemical criteria with the detection of DNA ladders after glucocorticoid treatment. The morphological and biochemical features observed in treated axolotls are in accordance with the criteria of apoptosis found in different models of mammalian lymphocyte programmed cell death. The onset of natural apoptosis was then detected by DNA fragmentation in thymus and in spleen during lymphocyte development and ontogenesis. A typical DNA ladder characteristic of apoptosis is detectable in the thymus as early as 5 months; apoptosis increases and peaks at 8 months, and is no longer detected by 10 months or thereafter. The ability of a superantigen, Staphylococcus aureus enterotoxin B (SEB), to induce T lymphocyte apoptosis in larvae was investigated as well. In vivo exposure of young axolotl larvae to SEB induces, as in mammals, thymocyte apoptosis as indicated by the enhancement of DNA fragmentation. These last results, natural programmed cell death and SEB induced apoptosis during thymic ontogeny, are discussed in correlation with what is known during mammalian thymic selection and apoptosis.     

Natural killer T cells and X-linked lymphoproliferative syndrome

PURPOSE OF REVIEW: Recent progress in elucidating the physiopathology of X-linked lymphoproliferative syndrome (XLP) has raised novel and important issues regarding the biology of natural killer T cells. Here I will review this information and discuss the issues involved. RECENT FINDINGS: XLP is a rare inherited immunodeficiency characterized by a high susceptibility to severe infection by the Epstein-Barr virus. Mutations in the gene SH2D1A (or alternatively SAP) underlie 80% of familial XLP (XLP-1) cases. Recently the remaining 20% of familial XLP (XLP-2) cases were shown to harbor mutations in the gene XIAP (X-linked inhibitor of apoptosis protein). Both SAP and XIAP deficiencies are associated with a defect in the development and/or homeostasis of natural killer T cells. SUMMARY: It can be hypothesized that the susceptibility to Epstein-Barr virus in XLP might result from the defect of natural killer T cells. The role of these cells in viral infection is unclear, but several herpes viruses have developed strategies to escape natural killer T cells. The discovery that SAP and XIAP deficiency leads to a defect in natural killer T cells has also shed light on novel signaling pathways required for natural killer T cell development and/or homeostasis.     

Apoptosis of colorectal adenocarcinoma (COLO 201) by tumour necrosis factor-alpha (TNF-α) and/or interferon-gamma (IFN-γ), resulting from down-modulation of Bcl-2 expression

Fas antigen is constitutively expressed in the normal colon epithelium, but considerably diminished in most colorectal carcinomas. In the present study, we examine the relationship between Fas antigen expression and apoptosis using the colorectal carcinoma cell line COLO 201, on which a low grade of Fas antigen is expressed. Anti-Fas antibody had no effect on the induction of apoptosis of COLO 201. However, TNF-α and/or IFN-γ, independently and additively, up-regulated Fas antigen expression on COLO 201 and induced apoptosis in a dose-dependent manner. Both cytokines also increased the COLO 201 sensitivity to anti-Fas antibody, resulting from the down-modulation of Bcl-2 and the up-regulation of Bax. These findings indicate that cytokine(s) plus anti-Fas antibody (which mimics natural Fas ligand) are more effective in inducing apoptosis of COLO 201 than cytokine(s) alone. These findings suggest that immunotherapy in combination with cytokine(s) and lymphokine-activated killer (LAK) cells will become a more effective therapy for cancer than cytokine(s) or LAK cells alone, since the Fas ligand is expressed on activated T cells, natural killer cells and macrophages.     

Effects of interferon-gamma and tumour necrosis factor-alpha on CD95/Fas ligand-mediated apoptosis in human blood eosinophils

Many cells, including eosinophils, express CD95 (Fas), a surface receptor that mediates apoptosis when ligated by specific antibodies or its natural ligand, Fas ligand (FasL). As apoptosis may play an important role in the regulation of tissue eosinophilia, factors that modulate eosinophil sensitivity to apoptosis are of great interest. It has previously been shown that interferon-gamma (IFN-gamma) and tumour necrosis factor-alpha (TNF-alpha) together increase CD95 surface expression on eosinophils. However, the functional consequences of this increase in CD95 expression have not been demonstrated in detail. We therefore investigated whether the increase in CD95 expression mediated by IFN-gamma/TNF-alpha indeed translates into increased, FasL-mediated apoptosis of eosinophils. For this purpose, purified eosinophils from normal donors were incubated with different concentrations of FasL and induction of apoptosis was assessed by annexin-V/propidium iodide assay. Unlike Jurkat cells, which became apoptotic within 2 h after incubation with FasL, an increase in eosinophil apoptosis could first be dedicated after 6 h incubation with FasL. Prestimulation with IFN-gamma/TNF-alpha for 24 h significantly enhanced FasL-induced apoptosis in eosinophils. This increase in CD95/FasL-mediated apoptosis was correlated with an IFN-gamma/TNF-alpha-mediated increase in CD95 expression. From these findings we conclude that the combination of IFN-gamma and TNF-alpha enhances CD95 expression, which results in an increase in FasL-mediated apoptosis of eosinophils in vitro.     

Cyclosporin A regulates human NK cell apoptosis induced by soluble HLA-I or by target cells

Human natural killer (NK) cells are effectors of innate immunity, capable of killing transformed or virus-infected cells and producing pro-inflammatory cytokines. Soluble molecules of HLA-I (sHLA-I), which are significantly increased in the serum of patients affected by auto-immune or infectious or neoplastic diseases, induce NK cell apoptosis interacting with its ligands, such as CD8 or the activating isoforms of members of inhibitory superfamily receptors (IRS). This cell death is accompanied by the release of large amounts of interferon-gamma. NK cells can kill autologous target cells, including antigen presenting cells or infected or tumor cells, by engaging the natural cytotoxicity receptors (NCR) NKp30, or NKp44 and NKp46. Again, the binding between NCR on NK cells and their putative ligands on targets leads to NK cell apoptosis. FasL produced and secreted by NK cells is responsible for the NK cell apoptosis induced by either HLA-I receptors or NCR. Interestingly, cyclosporin A (CsA) blocks NK cell death consequent to interaction with target cells or with sHLA-I, without affecting the activation of cytolysis. This would indicate that CsA can maintain NK cell-dependent innate immunity by prolonging NK cell survival in an hostile environment in the presence of sHLA-I or target cells.     

Apoptosis as a mechanism of natural resistance to HIV-1 infection in an exposed but uninfected population.

BACKGROUND: Apoptosis, also known as programmed cell death, has been reported not only as a pathogenic mechanism, but also as a mechanism of resistance and control of a variety of infections. Particularly during HIV-1 infection, apoptosis is the main mechanism by which infected and uninfected CD4+ lymphocytes are eliminated. However, apoptosis as a mechanism of natural resistance to HIV infection has this far not been explored. OBJECTIVE: To determine whether apoptosis could explain, at least in part, the natural resistance to HIV infection observed in some exposed but uninfected individuals (ESN). RESULTS: Our data shows that peripheral blood monocytes in the ESN group has a predisposition to undergo spontaneous apoptosis, as well as apoptosis induced by HIV infection in vitro, compared with monocyte population from the control group at low risk of HIV infection. CONCLUSIONS: These findings suggest that, in some ESN individuals, monocytes could play an important role in the control of HIV infection by undergoing apoptosis. However, since the variability among individuals is large, studies with larger cohorts focusing in monocyte apoptosis as pathogenic mechanisms are required.     

Role of lung surfactant in phagocytic clearance of apoptotic cells by macrophages in rats

Two of the common features of inflammatory lung diseases are the increased production of pulmonary surfactant and the induction of lung cell apoptosis. However, the relationship between these two events has not been addressed. To investigate the role of surfactant in pulmonary inflammation and apoptosis, we instilled natural lung surfactant (Survanta) (1.6-12.5 mg) into the rat lungs and determined the number of alveolar macrophages (AMs) and apoptotic lung cells. High-dose treatments of Survanta (>6.25 mg/rat) caused an increase in macrophage cell influx and lung cell apoptosis at 4 weeks post-treatment. In vitro studies using lavaged macrophages showed Survanta did not cause apoptosis. We then examined the role of Survanta on ability of macrophages phagocytizing apoptotic cells. This study demonstrated that macrophages were able to eliminate apoptotic cells more efficiently in the absence of surfactant than in its presence. In vivo, high doses of Survanta decreased the ability to clear exogenously instilled apoptotic cells or bacteria. Taken together, our results suggest that excessive accumulation of lung surfactant by Survanta treatment can impair or overwhelm the phagocytic clearance function of AMs and that this impairment may lead to increased presence of apoptotic cells in the lung and bacterial survival.     

Neuronal apoptosis in neurodegeneration

Apoptosis mediates the precise and programmed natural death of neurons and is a physiologically important process in neurogenesis during maturation of the central nervous system. However, premature apoptosis and/or an aberration in apoptosis regulation is implicated in the pathogenesis of neurodegeneration, a multifaceted process that leads to various chronic disease states, such as Alzheimer's (AD), Parkinson's (PD), Huntington's (HD) diseases, amyotrophic lateral sclerosis (ALS), spinal muscular atrophy (SMA), and diabetic encephalopathy. The current review focuses on two major areas (a) the fundamentals of apoptosis, which includes elements of the apoptotic machinery, apoptosis inducers, and emerging concepts in apoptosis research, and (b) apoptotic involvement in neurodegenerative disorders, neuroprotective treatment strategies/modalities, and the mechanisms of, and signaling in, neuronal apoptosis. Current and new experimental models for apoptosis research in neurodegenerative diseases are also discussed.     

Cytotoxic natural antibodies against human tumours: an option for anti-cancer immunotherapy?

Healthy individuals may contain in their peripheral blood antibodies which are able to destroy human tumour cells mediated either by complement-dependent cytotoxicity or by apoptosis. The largest proportion of these antibodies is of IgM isotype and directed against distinct tumour associated carbohydrate epitopes. Although the origin of these antibodies is not clear they seem to belong to the class of natural antibodies because they are not affinity matured and are encoded by distinct germ-line restricted gene families. It is most likely that this class of natural antibodies has in vivo an anti-tumour protective effect which may contribute to so-called tumour surveillance. On the other hand malignant tumour cells exert mechanisms to counteract such an antibody attack. These comprise soluble factors as well as cell surface expressed membrane complement regulatory proteins (mCRP). Further studies are needed to elucidate molecular mechanisms leading to either tumour destruction induced by natural antibodies or to overcome the protective strategies of the tumour against antibody attack.