生长抑素抑制内皮素刺激的家兔血管平滑肌细胞增殖

为探讨生长抑素（ＳＳＴ）对内皮素（ＥＴ）刺激细胞增殖的作用其机理，本工作在培养的兔主动脉血管平滑肌细胞（ＶＳＭＣ）上发现，１０＾－８ｍｏｌ／ＬＥＴ刺激细胞增殖（＾３Ｈ＝ＴｄＲ参入增多）和丝裂素活化蛋白激酶（ＭＡＰＫ）激活，１０＾－８ｍｏｌ／ＬＳＳＴ单独作用可抑制细胞增玩具增殖但不曩ＭＡＰＫ活性。ＳＳＴ不仅呈浓度依赖性地抑制ＥＴ刺激的ＶＳＭＣ增殖（Ｐ〈０．０１），而且亦抑制ＥＴ刺激的细胞ＭＡＰＫ激     

胸腺因子D对LAK细胞活性诱导的影响

本文报道利用ＭＴＴ法和４小时５１Ｃｒ释放法，在有或无ＩＬ－２存在的情况下，研究了ＴＦＤ对正常人ＰＢＭＣ体外增殖、ＬＡＫ活性诱导的影响。结果表明：单纯ＴＦＤ不能促进静止的淋巴细胞增殖，也不能诱导出高活性的ＬＡＫ细胞，但可促使经ＩＬ－２活化的淋巴细胞进一步增殖如先用ＩＬ－２活化淋巴细胞２４小时，再加入ＴＦＤ联合诱导，第４天时，ＬＡＫ活性可达８１．３±６．５％，明显高于单用ＩＬ－２组（Ｐ＜０．０１）。     

创伤后活化T细胞内cAMP代谢,蛋白激酶A活性的变化及意义

研究了创伤小鼠活化Ｔ细胞内ｃＡＭＰ代谢、蛋白激酶Ａ（ＰＫＡ）活性的变化及同Ｔ细胞功能的关系。结果显示，创伤后活化Ｔ细胞内ｃＡＭＰ含量增加，这一变化同创伤后Ｔ细胞白介素２（ＩＬ－２）生成减少，ＩＬ－２受体（ＩＬ－２Ｒ）表达受抑，Ｔ淋巴细胞转化（ＴＬＴ）降低密切相关。创伤后活化Ｔ细胞内腺苷酸环化酶（ＡＣ）、ＰＡＫ活性增加，ｃＡＭＰ－磷酸二酯酶（ｃＡＭＰ－ＰＤＥ）活性降低。ＰＫＡ抑制剂Ｈ－８在体外可明显     

CD80（B7）和CD86（B70）为T细胞的增殖、细胞因子的产生和CTL的生成提供相似的共刺激信号（文摘）

ＣＤ８０（Ｂ７）和ＣＤ８６（Ｂ７０）为Ｔ细胞的增殖、细胞因子的产生和ＣＴＬ的生成提供相似的共刺激信号（文摘）［英ＬｅｗｉｓＬ．Ｌａｎｉｅｒ…／／ＪＩｍｍｕｎｏｌ１９９５；１５４：９７］ＣＤ８０（Ｂ７）表达在活化的Ｂ细胞、Ｔ细胞、巨噬细胞和Ｄ细胞上；Ｃ...     

McAb共激活T细胞介导肝癌细胞前后的膜分子与TCRVβ基因的表达

Ｔ淋巴细胞活化是一个涉及多种膜表面分子和受体以及一系列相关多肽的复杂过程，为了使Ｔ细胞发挥更好的识别和杀伤癌细胞的功能，采用抗ＣＤ３、ＣＤ２８、ＣＤ８０（Ｂ７１）、ＣＤ２、ＣＤ５８ＭｃＡｂ分别刺激健康人ＰＢＬｓ后作用肝癌细胞，对作用前后ＰＢＬｓ用ＦＡＣＳ进行表型分析，结果发现：作用后ＣＤ３和ＣＤ８分子表达比作用前明显增高，而ＣＤ４分子无显著变化，同时基因家族采用ＲＴＰＣＲＳｏｕｔｈｅｒｎ印迹分析ＴＣＲＶβ基因１～２０亚家族表达水平与特征，健康人ＰＢＬｓ分别加入ＩＬ２、ＰＨＡ、抗ＣＤ３和ＣＤ３＋ＣＤ２８、ＣＤ２８＋ＣＤ８０、ＣＤ２＋ＣＤ５８作用肝癌细胞（ＢＥＬ７４０２）前表达水平平均约为５％，作用ＢＥＬ７４０２后表达水平约为１３％～２５％，其特征为Ｖβ７增高，这提示在癌抗原的参与下ＭｃＡｂ共刺激的Ｔ细胞活化，ＴＣＲ接受ＡＰＣ相应抗原的刺激，具有该ＴＣＲ的淋巴细胞迅速增殖而成为针对抗原的Ｔ细胞克隆，发挥其识别和杀伤癌细胞的作用，这将为肿瘤生物治疗的研究提供分子免疫学依据。     

系统性红斑狼疮患者CD28表达及其意义

ＣＤ２８是Ｔ细胞激活中重要的共刺激分子。为了解Ｂ７－Ｃ礤刺激途径在系统性红斑狼疮（ＳＬＥ）中的作用，我们对３０例期ＳＬＥ２外周血Ｔ细胞ＣＤ２８的表达进行了检测，并分析了其激活后凋亡情况。结果表明，ＳＬＥ组的ＣＤ２８Ｔ细胞低于正常对照组，在抗ＣＤ３单抗刺激后ＣＤ２８细胞凋亡率增加。这提示ＳＬＥ中Ｂ７－ＣＤ２８共刺激途径介导的ＡＩＣＤ可能导致ＳＬＥ中的Ｔ细胞淋巴细胞贫血症。     

肾上腺髓质素对内皮素促家兔气道平滑肌细胞增殖的抑制作用

在体外培养的家兔气道平滑肌细胞（ＡＳＭＣ）上，观察肾上腺髓质素（ＡＭ）对内皮素（ＥＴ）促ＡＳＭＣ增殖的影响及丝裂素活化蛋白激酶（ＭＡＰＫ）活性的变化。以探讨ＡＭ对ＡＳＭＣ增殖的调控。结果显示１０－８ｍｏｌ／ＬＥＴ－１显著刺激ＡＳＭＣ３Ｈ－ＴｄＲ参入及ＭＡＰＫ激活（Ｐ＜０．０１）。ＡＭ（１３－５２）呈剂量依赖地抑制ＥＴ－１的上述作用（Ｐ＜０．０５，Ｐ＜０．０１）。单独应用ＡＭ（１３－５２）对ＡＳＭＣ３Ｈ－ＴｄＲ参入及ＭＡＰＫ活性无明显影响。表明ＡＭ（１３－５２）可抑制ＡＳＭＣ对ＥＴ－１的增殖反应，其机理可能涉及ＭＡＰＫ活性的抑制。     

多发性骨髓瘤细胞XG—7诱导CD8和TCRαβ阳性的T细胞增殖分？…

采用经密度梯度离心获得的正常健康人外周血淋细胞（ＰＢＬ）与多发性骨髓瘤细胞ＸＧ－７进行混合肿瘤淋巴细胞脱养。＾３Ｈ－ＴｄＲ掺入实验证实ＸＧ－７细胞可刺激ＰＢＬ增殖;间接免疫荧光检测显示增殖的ＰＢＬ中,ＣＤ４＾＋／ＣＤ８＾＋细胞比例偏移,ＣＤ８＾＋Ｔ细胞增加。激活的ＣＤ８＾＋Ｔ细胞在含ＩＬ－２的培养体系中得到迅速扩增,占细胞总数的９６％以上。流式细胞仪检测显示,扩增的Ｔ细胞表达ＣＤ３,ＣＤ８和ＴＣＲ     

蛋白酪氨酸激酶及TCR激活途径

存在于淋巴细胞中的多种蛋白酪氨酸激酶（ＰＴＫ）与淋巴细胞表面分子有结构联系，刺激Ｔ淋巴细胞表面特异的抗原受体（ＴＣＲ）可以活化ＰＴＫ。活化的ＰＴＫ又与多种胞内效应分子作用，并通过它们介导级联反应，开启磷酸肌醇途径、激活Ｒａｓ及有丝分裂原活化蛋白激酶（ＭＡＰＫ），进而活化核内因子，最终诱导Ｔ淋巴细胞的活化与增殖。     

McAb共激活T细胞介导肝癌细胞前后的膜分子与TCR Vβ基因的 …

Ｔ淋巴细胞活化是一个涉及多种膜表面分子和受体以及一系列相关多肽的复杂过程，为了使Ｔ细胞发挥更好的识别和杀伤癌细胞的功能，采用抗ＣＤ３、ＣＤ２８、ＣＤ８０（Ｂ７．１）、ＣＤ２、ＣＤ５８ＭｃＡｂ分别刺激健康人ＰＢＬｓ后作用肝癌细胞，对作用前后ＰＢＬｓ用ＦＡＣＳ进行表型分析，结果发现：作用后ＣＤ３和ＣＤ８分子表达比作用前明显增高，而ＣＤ４分子无显著变化，同时基因家族采用ＲＴ－ＰＣＲ－Ｓｏｕｔｈｅｒｎ印迹     

Inhibition of the protein kinase C pathway promotes anti-CD95-induced apoptosis in Jurkat T cells

The role of the basal activity of the serine/threonine protein kinase, protein kinase C (PKC) in the regulation of anti-CD95-induced apoptosis in Jurkat T cells was investigated. The PKC-specific inhibitor GF 109203X and the proposed cPKC-specific inhibitor Go 6976, in a concentration-dependent manner, increased the percentage of cells undergoing apoptosis induced by anti-CD95 mAb as demonstrated by propidium iodide (PI) staining, TUNEL assay and DNA fragmentation by gel electrophoresis. Furthermore, Go 6976 and GF 109203X abrogated phorbol myristate acetate-induced inhibition of anti-CD95-induced apoptosis. To examine the molecular mechanism by which PKC modulates anti-CD95-induced apoptosis, the effects of Go 6976 on known effector and regulatory molecules of cell death were studied. Increased recruitment of cells undergoing apoptosis was associated with enhanced anti-CD95-induced proteolytic cleavage of the most receptor-proximal cysteine protease caspase-8, subsequent cleavage and activation of the machinery protease caspase-3, and cleavage of the caspase substrates DNA-dependent protein kinase catalytic subunit, poly-(ADP-ribose) polymerase and lamin B1. CD95 and FADD protein levels in Jurkat T cells were not altered by Go 6976 treatment. In addition, Go 6976 did not alter protein levels and subcellular distribution of the anti-apoptotic molecules Bcl-2 and Bcl-xL. These data suggest indirectly that basal PKC activity acts at an early stage in the anti-CD95-induced caspase pathway to attenuate subsequent activation of downstream effector molecules and associated apoptosis in Jurkat T cells.      

Comparison of interleukin 2 and 12-O-tetradecanoyl-phorbol 13-acetate as signals for protein kinase C activation in purified human T lymphocytes

Interleukin 2 (IL2) and 12-O-tetradecanoylphorbol 13-acetate (TPA) have been compared for their ability to induce translocation of protein kinase C (PKC) in T lymphocytes prestimulated with anti-CD3 monoclonal antibody (mAb), either in the presence or absence of monocytes. TPA alone did not promote purified T cell growth, but it was able to induce a transient, within 30 min, translocation of PKC activity. The profiles of PKC association with the membrane of the T cells under TPA stimulation were quite similar when either the anti-CD3 mAb or the fixed monocytes, or both, were added to the T cells. The decrease of cytosolic PKC under TPA stimulation was less pronounced for the purified T cells stimulated with anti-CD3 mAb, fixed monocytes alone or both than for unstimulated purified T cells. Even in the absence of monocytes, the addition of exogenous IL2 to the anti-CD3 mAb-treated T cells resulted in PKC translocation, with a transient increase in the PKC activity found in both the particulate and cytosolic fractions. When exogenous IL2 was added to the proliferating T cells, the association of PKC with the membrane was prolonged and the activity did not reach a plateau during the first 2 h after the IL2 stimulation. In parallel, the level of PKC associated with the membrane was higher in proliferating cells than in resting cells even 4 days after stimulation. These results suggest that activation of PKC by IL2 might be different from the direct activation of PKC by TPA and that a specific activation pathway, at least kinetically distinct from the classical phosphatidyl inositol diphosphate degradation by phospholipase C, might be involved during IL2 stimulation of T lymphocytes through high-affinity IL2 receptors.     

抗CD28＋B7．1单抗共刺激T细胞诱导肝癌细胞凋亡的第二信使系统研究

目的：探讨T淋巴细胞活化、增殖、诱导肝癌细胞凋亡过程中第二信使系统的调控机制。方法：用CD28＋B7．1（CD80）单克隆抗体共刺激T淋巴细胞诱导肝癌细胞（BLE－7402）凋亡,测定不同诱导时间T细胞内cAMP,cGMP和Ca^2 的浓度改变及肝癌细胞凋亡情况。结果：活化的T淋巴细胞中,cAMP浓度在初期短暂升高,继而快速下降,作用于肝癌细胞后逐步回升至1－2倍,而细胞内cGMP的浓度急剧升高6－7倍,Ca^2 浓度也显著增加2－3倍,且均在第4天达最高值,与癌细胞的凋亡呈正相关,结论：T淋巴细胞内第二信使系统cAMP、cGMP和Ca^2 的水平与细胞的活化增殖、杀伤效应密切相关。     

T cell receptor/CD3 and CD28 use distinct intracellular signaling pathways.

Ligation of the T cell membrane antigen CD28 strongly enhances cytokine secretion in human T lymphocytes that are activated via T cell receptor (TcR)/CD3 or CD2 molecules. This study was undertaken to investigate whether, as has been indicated for activation via TcR/CD3, stimulation via CD28 is dependent on the activation of protein kinase C (PKC). Two inhibitors of PKC, 1-alkyl 2-methyl-glycerol and staurosporine, caused a dose-dependent inhibition of T cell proliferation induced by anti-CD3 monoclonal antibodies (mAb). The induction of interleukin (IL) 2 secretion was found to be more sensitive to the effects of the PKC inhibitors than the up-regulation of IL 2 receptor expression. In marked contrast, the anti-CD28 mAb-mediated enhancement of T cell proliferation and IL 2 secretion were insensitive to the action of either compound. We conclude that two independent signaling pathways may be operational in human T cells. The first used by TcR/CD3 depends on the activation of PKC, whereas the second is employed by CD28 and functions independently of PKC.     

SH2A 基因对细胞信号转导的影响及其亚细胞定位

目的 研究Src同源域2(src homology 2，SH2)A基因在细胞信号转导中的作用并进行亚细胞定位。方法 通过RT—PCR方法扩增SH2A cDNA编码序列，构建真核重组表达载体pcDNA3．1-SH2A，利用脂质体转染肝癌Bel7402细胞、COS7细胞，检测蛋白酶C(protein kinaseC，PKC)、酪氨酸蛋白激酶(tyrosine protein kinase，TPK)、丝裂原激活蛋白激酶(mitogen activated protein kinase，MAPK)活性的改变；另构建pEGEP—SH2A，转染同前，荧光显微镜观察荧光定位。结果 测序结果显示真核重组表达载体pcDNA3．1-SH2A及pEGFP—SH2A中均含有SH2AcDNA编码序列；肝癌Bel7402细胞、COS7细胞转染pcDNA3．1-SH2A后，胞浆PKC的活性下降了40％左右，MAPK和TPK活性未见明显改变。荧光显微镜观察发现SH2A基因在细胞质中表达。结论 SH2A基因编码蛋白在PKC信号转导通路中起抑制作用；SH2A基因编码蛋白定位于细胞质。     

Antibody valence and induced signal transduction: the role of antibody valence in anti-CD3-induced signal transduction in isolated normal T cells

This report provides direct evidence that protein kinase C (PKC) is activated in isolated, rigorously accessory cell (AC)-depleted T cells when the T cell antigen recognition complex is stimulated by divalent anti-CD3 monoclonal antibody. Anti-CD3 monoclonal antibody-stimulated PKC activation alone does not, however, directly stimulate T cell proliferation in the absence of AC. A rise in cytosolic calcium is the second signal believed to be of paramount importance in T cell activation. While mitogenic concentrations of some divalent anti-CD3 antibodies do not cause a rise in cytosolic calcium, polyvalent anti-CD3 does evoke increased intracellular Ca2+ in rigorously AC-depleted resting human T cells.     

Anti-alpha 4 integrin antibody induces apoptosis in murine thymocytes and staphylococcal enterotoxin B-activated lymph node T cells.

We have shown that an antibody (9C10) to the alpha 4 integrin induces apoptosis in murine immature CD4+ CD8+ thymocytes and in activated (but not resting) mature lymph node T cells. In both cases, apoptosis is blocked by the highly selective protein kinase C (PKC) inhibitor Ro31.8425, suggesting that 9C10 induces signalling through the alpha 4 integrin resulting in PKC activation leading to apoptosis. Overall, our results indicate the potential role of the alpha 4 integrin-mediated interactions in apoptosis induction during T-cell development and following mature T-cell activation.     

Rescue from anti-IgM-induced programmed cell death by the B cell surface proteins CD20 and CD40.

Programmed cell death (PCD), or apoptosis, is characterized by several morphologic alterations and eventual cleavage of nuclear DNA into oligonucleo-some-length fragments. We defined a human B cell line, Ramos, that responds with PCD following ligation of surface IgM. Of the DNA in Ramos cells 3%-10% was fragmented as early as 4 h after IgM ligation. Propidium iodide staining demonstrated that 20%-40% of Ramos cells became apoptotic by 18 h and further established that cells transiting into the S phase of the cell cycle were susceptible to PCD. Addition of several agents to the Ramos cells abrogated anti-IgM-induced PCD, including the phorbol 12-myristate 13-acetate (PMA). In contrast to the effect of PMA, the 4 alpha PMA isomer of PMA neither activated protein kinase C (PKC) nor rescued the cells from anti-IgM-induced PCD, confirming a role for PKC in negating apoptosis. To explore the effect of physiologic signals on anti-IgM-induced PCD, antibodies against the CD20 or CD40 molecules were added in concert with anti-IgM. Both CD20 and CD40 synergize with anti-IgM to augment proliferation but neither molecule activates PKC in Ramos cells. Both anti-CD20 and anti-CD40 reduced the number of cells undergoing anti-IgM-induced PCD. Unlike the effect of anti-CD40, addition of anti-CD20 to anti-IgM-stimulated cells negated PCD only in a subset of cells. Maximal rescue occurred following the addition of anti-CD40 and occurred by 4 h and at least up to 20 h of culture. These data show that (a) PCD can be initiated in B cells entering the S phase of the cell cycle, (b) PCD can be triggered by engagement of surface IgM in the absence of ancillary signals or PKC activation, and (c) rescue from PCD can occur by several mechanisms, either PKC dependent or PKC independent.     

T cell activation by a Trypanosoma brucei brucei-deriyed lymphocyte triggering factor is dependent on tyrosine protein kinases but not on protein kinase C and A

Trypanosoma brucei brucei releases a lymphocyte-triggering factor (TLTF) that activates CD8⁺ T cells. We here study second messenger mechanisms in this activation, i. e. the effects of protein kinase C (PKC), protein kinase A (PKA) and tyrosine kinases (TPK) inhibitors on TLTF-induced interferon-γ (IFN-γ) secretion and proliferation in lymphoid cell cultures. The effects were compared to those obtained by phytohemagglutinin (PHA) stimulation. Rat spleen mononuclear cells (MNC) and spleen MNC from a mutant mouse strain possessing CD8⁺ T cells but lacking CD4⁺ T cells were used as responder cells. Although both the PKC and the PKA inhibitors suppressed PHA-induced IFN-γ secretion and proliferation of rat MNC and mouse CD8⁺CD4^? MNC, they had no effect on the same TLTF-induced responses. The TPK inhibitor genistein, however, strongly suppressed TLTF-induced activation of both types of responder cells to IFN-γ secretion and the TLTF-induced proliferation of mouse CD8⁺CD4^? MNC. The suppressive effects of the drugs could be overcome by ionomycin and tetradecanoylphorbol acetate, which show that the effects were not due to drug nonspecific cellular toxicity of the drugs. We conclude that TLTF activates CD8⁺ T cells through pathways other than the PKC- or PKA-dependent signal transduction, and that TPK may be involved in the triggering.