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1.
目的 克隆获得编码人补体膜辅助调节蛋白( MCP) 的cDNA,并对其在真核细胞的表达及功能进行研究。方法 应用RTPCR 方法,从U937 细胞总RNA 中扩增编码人MCP 分子的cDNA片段, 快速克隆于pGEMTEasy 载体,测定其序列。将该片段重组于pLXSN 载体,电穿孔转染NIH3T3 细胞,经FACS 检测筛选表达MCP 的阳性细胞克隆,用补体溶破试验鉴定其抑制人补体溶破的功能。结果 RTPCR 扩增得到1 144bp 的编码人MCP 分子的cDNA 片段,序列分析表明该cDNA编码的蛋白为STC+ CYT2 亚型。细胞转染筛选获得多个表达MCP 的NIH3T3 阳性细胞克隆,补体溶破试验证实其具有抑制人补体经典途径和旁路途径溶破的功能。结论 本研究为进一步探讨不同亚型结构的MCP 分子与功能的关系及其应用奠定了基础。  相似文献   

2.
CD46 (membrane cofactor protein) is a cell surface complementregulatory glycoprotein that facilitates enzymatic cleavageof complement component C3b; it is expressed by both human oocytesand acrosome-reacted spermatozoa. Murine anti-CD46 monoclonalantibody (mAb) has been reported to decrease significantly theability of human spermatozoa to penetrate hamster oocytes. Wehave investigated the effect of purified anti-CD46 mAbs on spermatozoon-oocyteinteraction in an autologous zona-free oocyte penetration test.Oocytes and/or spermatozoa were preincubated with either oftwo anti-CD46 murine mAbs, TRA.2.10 (a non-blocking mAb) andMH61 (a mAb that functionally blocks C3b-ligand binding activity),or a control isotype-matched mAb, in medium supplemented withhuman serum albumin. Preincubation of both spermatozoa and zona-freeoocytes with TRA.2.10, but not MH61, caused a significant decreasein the number of oocytes showing sperm binding and pronuclearformation (9/23) compared with controls (21/26) in this complementcomponent-depleted medium. This effect was not observed if oocytesor spermatozoa alone were preincubated. These data suggest thatCD46 has a role in human spermatozoon-oocyte interaction atthe level of the ooocyte plasma membrane, and indicate thata novel function other than direct C3b binding could be involved.  相似文献   

3.
目的:建立稳定表达绿色荧光蛋白(GFP)的人脐静脉血管内皮细胞(HUVECs),研究小干扰RNA(siRNA)对HUVECs中GFP表达的抑制作用。 方法: 用lipofectamine2000将编码GFP的质粒pN3-EGFP转入HUVECs中。用G418筛选并维持已转化pN3-EGFP的HUVEC(HUVEC-GFP)。利用T7 RNA转录试剂盒,制备可抑制GFP基因表达的siRNA(GFPsiRNA)和无关对照的RNA(control siRNA)。用oligofectamine将siRNA转入HUVEC-GFP中。继续培养48 h后,检测HUVEC-GFP中GFP蛋白和mRNA表达水平。 结果: 用G418筛选获得了HUVEC-GFP细胞株,可以观察到GFP的稳定表达。HUVEC-GFP转化siRNA后48 h,GFP的荧光强度明显下降,而对照组的荧光强度无明显下降。半定量RT-PCR检测显示,GFPsiRNA对GFP mRNA表达有较强的抑制作用,抑制率达40%,而control siRNA对GFP mRNA表达水平无明显的抑制作用。 结论: 利用体外转录合成的siRNA能有效地抑制HUVECs中GFP的表达。  相似文献   

4.
CD46 (membrane cofactor protein) is a human cell-surface regulator of activated complement and a receptor for the measles virus. A CD46 transgenic mouse line with an expression pattern similar to that of human tissues has been produced, to develop an animal model of (i) the control of complement activation by complement regulators in hyperacute rejection of xenografts, and (ii) measles virus infection. The mouse line was made using a CD46 minigene that includes promoter sequence and the first two introns of genomic CD46, which was coinjected into mouse ova with chicken lysozyme matrix attachment region DNA. A high level of CD46 expression in homozygotic transgenic mice was obtained with spleen cells having approximately 75% of the level found on human peripheral blood mononuclear cells. CD46 was detected in all tissues examined by immunohistochemistry, radioimmunoassay and Western blotting, showing that these mice were suitable for transplantation and measles virus infection studies. It also indicated that the transgene included the important regulatory elements of the CD46 promoter. Transgenic spleen cells were significantly protected in vitro from human complement activated by either the classical or alternative pathways and from alternative pathway rat complement. Furthermore, transgenic mouse hearts transplanted to rats regulated complement deposition in an in vivo model of antibody-dependent hyperacute xenograft rejection. Similar to human lymphocytes, transgenic lymphoblasts could be infected in vitro with measles virus; infected cells expressed viral proteins and produced infectious viral particles. The data demonstrate the suitability of this minigene for obtaining high-level CD46 expression sufficient for enhanced resistance of transgenic cells to complement attack and for obtaining wide tissue distribution of CD46, analogous to human tissues and, therefore, useful for comparative studies.  相似文献   

5.
Expression of the complement-regulatory proteins (CRP) CD46, CD55 and CD59 represents a strategy used by tumor cells to evade complement-dependent cell cytoxicity stimulated by monoclonal antibodies. We have isolated two single-chain variable fragments (scFv) to CD55 and CD59 from a human phage-display library and from these scFv we have produced two miniantibodies (MB), MB-55 (against CD55) and MB-59 (against CD59), containing the human hinge-CH2-CH3 domains of IgG1. The specificity of the two MB for the corresponding CRP was assessed by ELISA using purified CD46, CD55 and CD59. MB-55 and MB-59 neutralized the inhibitory activity of CD55 and CD59, respectively, restoring the complement-mediated lysis of sheep and guinea pig erythrocytes that was otherwise inhibited by the two CRP. FACS analysis revealed binding of MB-55 and MB-59 to the lymphoma cell line Karpas 422. The two MB induced a two-fold increase in the complement-dependent killing of these cells stimulated by Rituximab, a chimeric anti-CD20 monoclonal antibody. Transfection of HEK293T cells with vectors encoding MB-55 or MB-59 markedly reduced the expression of CD55 and CD59. We conclude that the human antibodies MB-55 and MB-59 may represent a therapeutic tool to increase the complement-dependent killing activity of Rituximab in the treatment of non-Hodgkin's lymphoma.  相似文献   

6.
目的:探讨重组可溶性人CD40L(rsh CD40L)对人脐静脉内皮细胞(HUVECs)的损伤作用及其在动脉粥样硬化中的作用。方法:应用rsh CD40L刺激人脐静脉内皮细胞12 h;MTS法观察HUVECs的生存活性,ELISA法测内皮细胞E-选择素(E-selectin)、细胞间黏附分子(ICAM)-1、组织因子(TF)、组织因子途径抑制物(TFPI)表达的变化,比色法测脂质过氧化物丙二醛(MDA)含量及超氧化物歧化酶(SOD)活力。结果:与正常组比较,不同浓度的rsh CD40L(0.5、1、2、3 mg/L)对内皮细胞的生存活性无明显影响;0.5 mg/L rsh CD40L即可增加内皮细胞E-selectin、s ICAM-1、TF、TFPI的分泌,差异有统计学意义(P0.01),同时增加内皮细胞MDA的含量、降低SOD活性(P0.05)。结论:0.5~3 mg/L rsh CD40L对内皮细胞生存活性无明显影响,但已经引起内皮细胞功能障碍,增加内皮细胞炎症和外源性凝血反应,诱导内皮细胞脂质过氧化物损,使其抗氧化能力下降。  相似文献   

7.
A sperm protein of molecular mass 43 kDa (the spermatozoa membrane cofactor protein, smMCP) and a seminal plasma protein of 60 kDa (ssMCP) were identified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) followed by immunoblotting with four monoclonal antibodies (mAb) against membrane cofactor protein (MCP, CD46).These proteins served as factor I cofactors for the cleavage of methylamine-treated C3 (C3ma), the activity of which was blocked by M75, an MCP cofactor-activity-blocking mAb. Thus, these semen proteins are antigenic and functional homologoues of MCP. On SDS-PAGE analysis these MCP migrated as single-band proteins which differed from the two-band forms of MCP expressed on other cells. smMCP was N-glycosylated but not O-glycosylated, while ssMCP was O-glycosylated: after deglycosylation of these proteins bands were detected at 38-40 kDa and 43 kDa on SDS-PAGE, respectively. These semen MCP are therefore, structurally different from the conventional MCP. ssMCP in both normal and “sterile” subject groups was determined by sandwich enzyme-linked immunosorbent assay. Seminal plasma in the two groups contained 250-700 ng/ml ssMCP. The difference between the two groups was marginal, although samples from normal subjects tended to show higher concentrations of ssMCP than samples from “sterile” subjects. No molecular difference was observed with ssMCP and smMCP in the two groups by SDS-PAGE/immunobloblotting analysis. Immunohistochemical analysis suggested that MCP was positive in glandular epithelial cells and the lumen of the prostate, and in most intra-lumen cells of the testis. Using antibody M177, solubilized prostate and testis were analyzed by immunoblotting and compared with other cell MCP The major band of MCP in the testis, but not in the prostate, was of 60 kDa, which aligned with ssMCP. No band of testis or prostate MCP, however, aligned with smMCP. ssMCP may be produced in the testis, while the origin of smMCP remains unknown. We hypothesize that ssMCP is important in the survival of spermatozoa, protecting them against local secretion of immunoglobulin and complement in the female genital tract, and that smMCP, which is expressed on acrosome-reacted spermatozoa, plays an essential role in the interaction of spermatozoa with oocytes.  相似文献   

8.
目的:观察不同剂量活化蛋白C(APC)对脂多糖(LPS)诱导的人脐静脉血管内皮细胞(HUVECs)凋亡的作用。方法:将培养成功的HUVECs通过LPS(1 mg/L)孵育诱导细胞凋亡模型,并给予APC(10 μg/L)或APC(50 μg/L)建立药物治疗组,同时设立正常对照细胞组和单独LPS(1 mg/L)诱导细胞凋亡组。应用电镜观察细胞超微结构;DNA ladder与TUNEL荧光染色法检测细胞凋亡情况;Annexin-Ⅴ/PI双标记行流式细胞仪测定定量观察细胞凋亡率。同时采用MTT法测定细胞存活率和Western blotting测定增殖细胞核抗原(PCNA),以观察细胞的增殖变化。结果:通过细胞形态,DNA ladder和TUNEL荧光染色发现单独LPS诱导组的细胞可见明显的凋亡现象,而通过APC治疗组的细胞凋亡改变明显减轻和细胞凋亡率下降,同时细胞存活率和PCNA表达率增高,尤其在50 μg/L时,与单独LPS诱导组细胞比较差异显著(P<0.05)。结论:APC拮抗LPS诱导的血管内皮细胞凋亡并促进细胞的增殖,发挥保护细胞的作用。  相似文献   

9.
10.
目的:探讨LPS、TNF-α、IL-1β对人脐静脉内皮细胞(HUVEC)环氧合酶2(COX-2)表达及前列腺素(PGs)的影响。方法:在分离培养的HUVEC细胞给予LPS、TNF-α、IL-1β刺激24h后,采用原位杂交、逆转录-聚合酶链反应(RT-PCR)、免疫组化检测HUVECCOX-2mRNA及蛋白的表达并观察了培养液前列腺素(PGs)的变化。结果:静息状态的HUVEC表达极少量的COX-2;受炎性刺激后,HUVEC大量表达COX-2mRNA及蛋白,同时伴有PGs的升高。结论:结果提示,静息状态下HUVEC表达极少量的COX-2,炎性刺激可诱发COX-2高表达和PGs升高,因此内皮细胞可通过COX-2的调节参与炎症反应。  相似文献   

11.
The association of human herpesvirus 6 (HHV-6) and multiple sclerosis (MS) has been supported by several immunological and molecular studies. Recently, membrane cofactor protein (CD46) has been identified as the cellular receptor for the A and B variants of HHV-6. Elevated levels of soluble CD46 (sCD46) have been reported in the serum and CSF of MS patients. The aim of this study was to investigate a possible correlation between elevated levels of soluble CD46 and the presence of serum HHV-6 DNA in MS patients. An immunoaffinity column comprised of immobilized monoclonal antibodies to CD46 was developed to isolate sCD46 from cell free body fluids of MS patients and controls. After immunoaffinity purification, DNA was extracted from anti-CD46 column eluates and subjected to PCR amplification. Of the 42 MS samples tested, 4 serum samples were HHV-6 positive, 3 of which were typed as HHV-6A. The co-purification of sCD46 and HHV-6 DNA from MS sera indicates that HHV-6 is tightly connected to its receptor, CD46, in the serum of MS patients.  相似文献   

12.
目的:探讨脱氢表雄酮(DHEA)对干扰素-γ(I NF-γ)刺激下的人脐静脉内皮细胞(HUVECs)CD40/CD40L表达的影响。方法:原代培养人脐静脉内皮细胞,给予I NF-γ刺激和不同浓度DHEA干预。采用流式细胞术检测CD40/CD40L在细胞表面的表达,通过反转录-聚合酶链反应(RT-PCR)检测CD40/CD40L mRNA的表达。结果:I NF-γ刺激HUVECs表达CD40/CD40L,DHEA下调I NF-γ诱导的HUVECs表面CD40/CD40L的表达,同时对I NF-γ刺激下的CD40/CD40L mRNA的表达有抑制作用,并且呈剂量依赖性。结论:DHEA能减轻I NF-γ刺激下的人脐静脉内皮细胞CD40/CD40L的表达。  相似文献   

13.
14.
Molecular cloning of a pig homologue of membrane cofactor protein (CD46)   总被引:2,自引:0,他引:2  
Organs of transgenic pigs that express human complement regulatory proteins are under assessment as an alternative to transplantation. A major barrier to the transplantation of pig organs is the hyperacute rejection caused by pre-existing antibodies and complement. Pig cells are very susceptible to human complement, presumably because pig cell- surface complement regulatory proteins are inefficient against it. Expression of human complement regulatory proteins, such as decay- accelerating factor and membrane cofactor proteins (MCP or CD46), by means of transgenes would confer resistance to human complement upon pig cells, thereby preventing hyperacute rejection. To express sufficient levels of human complement regulatory proteins at appropriate sites, regulatory elements of genes of pig membrane-bound complement regulatory proteins would be useful. To obtain their cDNAs, we transfected human cells with a pig cDNA library, selected cells by incubation with pig complement and rescued the plasmids. We cloned a cDNA for the pig homologue of MCP, pMCP. The cDNA encoded a predicted protein of 363 amino acids with 42% amino acid identity with human MCP. The pMCP consisted of four short consensus repeats, a Ser/Thr/Pro-rich domain, and transmembrane and cytoplasmic domains. Recombinant soluble pMCP that lacked transmembrane and cytoplasmic domains had factor I cofactor activity in C3b cleavage, indicating that it is functionally, as well as structurally homologous to MCP. FACS analysis with anti-pMCP mAb demonstrated that pMCP is expressed on all blood leukocytes, erythrocytes, and on endothelial and epithelial cell lines.   相似文献   

15.
The progressive renal disease model of chronic uninephrectomy-desoxycorticosterone-trimethylacetate (UNX-DOCA) hypertension is associated with mesangial proliferation as a major disease mechanism. A detailed structural analysis of the alterations in glomerular structure which accompany the development of sclerosis in this model has not been made. Male Munich-Wistar rats underwent UNX, received weekly injections of the aldosterone agonist DOCA and 1% sodium chloride as drinking solution and were compared with sham operated controls (CON). Thirty eight days after onset, UNX animals had an albuminuria of 183±180 mg/day versus 0.38±0.22 mg/day in CON. Kidneys were fixed by total body perfusion and renal tissue processed for light and electron-microscopy. Superficial and deep total glomerular volume increased from 2.18±0.15 (deep: 2.57±0.24) 106 m3 in CON to 3.98±0.81 (deep: 3.95±0.63) 106 m3 in UNX. In addition to overall tuft hypertrophy, structural analysis revealed severe destruction of tuft architecture with mesangial expansion and/or capillary ballooning, leading to local tuft enlargements. Podocytes overlying the expanded areas appeared unable to adapt to cover the increased tuft surfaces. They developed severe lesions in cell architecture leading to denudation of glomerular basement membrane (GBM)-areas. Naked GBM appears to represent a nidus for hyalinosis, thrombosis and synechia formation, which progresses to segmental sclerosis. In the UNX-DOCA model of chronic glomerular hypertension local mesangial expansion was frequently encountered but no evidence was found that mesangial proliferation and matrix production proceeded to sclerosis. The crucial damage to the glomerulus in this model would appear to be attributable to podocyte failure, with the resultant GBM denudation triggering synechia formation, hyalinosis and ultimately glomerulosclerosis.  相似文献   

16.
目的:观察LPS对脐静脉血管内皮细胞(HUVECs)表达组织纤溶酶原激活物(tPA)和纤溶酶原激活物抑制物1(PAI-1)的影响。 方法: 用生长良好的第2、3代HUVECs进行试验。用cell counting kit-8(CCK-8)测定LPS刺激后细胞活性变化;发色底物法测定LPS组和对照组培养液中tPA, PAI-1活性;RT-PCR检测细胞内tPA和PAI-1 mRNA水平。 结果: 与对照组相比,LPS(10 mg/L)对细胞活性没有明显差异。LPS诱导PAI-1活性在24-72 h显著升高(P<0.05),且显著上调PAI-1 mRNA,24 h达到峰值,以后渐降,72 h达到正常水平。而LPS组与对照组tPA活性与tPA mRNA无明显差异(P>0.05)。 结论: LPS(10 mg/L)可显著上调PAI-1 mRNA转录和分泌而不影响tPA mRNA,结果提示LPS可活化内皮细胞,诱发PAI-1 mRNA表达和蛋白分泌而抑制纤溶系统,这有利于微血栓的形成、血栓稳定,血液凝固和DIC发生。  相似文献   

17.
目的:研究克拉屈滨对人脐静脉内皮细胞EA.hy926生长及分泌活性的影响,探讨克拉屈滨通过抑制内皮细胞活力发挥抗肿瘤的作用机制。方法:采用CCK-8法检测不同浓度(0.4~1μmol/L)克拉屈滨对内皮细胞活力的影响;用流式细胞术检测细胞周期和细胞凋亡率;Western blot检测细胞凋亡和周期相关蛋白的表达水平;用ELISA法检测上清液肿瘤坏死因子α(tumor necrosis factor-α,TNF-α)、转化生长因子β1(transforming growth factor-β1,TGF-β1)和血管内皮生长因子(vascular endothelial growth factor,VEGF)的水平;Gries法检测上清液一氧化氮(nitric oxide,NO)含量。结果:克拉屈滨作用48 h对细胞活力有明显的抑制作用,其半数抑制浓度约为3.644μmol/L,随药物浓度升高和作用时间的延长而抑制作用增强。克拉屈滨作用48 h后,细胞周期被明显阻滞在S期,0.4μmol/L时S期细胞约43.74%,1μmol/L时S期细胞约77.23%。克拉屈滨处理后,各组内皮细胞的凋亡率没有显著差异。克拉屈滨处理后,caspase-3与Bax蛋白水平无明显差异;p21水平随着药物浓度增加而增高,而p53水平随着药物浓度增加而降低(P0.05)。克拉屈滨处理后,上清液中TGF-β1和TNF-α水平升高,VEGF含量减少(P0.05)。克拉屈滨处理后,上清液中NO含量减少(P0.05)。结论:克拉屈滨能明显抑制内皮细胞EA.hy926的活力,其主要机制与细胞周期阻滞有关。同时克拉屈滨能促进内皮细胞EA.hy926分泌TNF-α和TGF-β1,抑制其分泌VEGF和NO。  相似文献   

18.
 目的: 探讨以异种后弹力膜/基质为载体诱导人脐静脉内皮细胞向角膜内皮细胞分化的可行性及移植术后在活体的生理功能。方法:体外分离培养脐静脉内皮细胞作为诱导移植的种子细胞;取当地质检合格的猪眼球以直径6.2 mm、厚100 μm、冷冻脱水进行角膜深板层载体的制备;接种经CM-DiI荧光标记的第2~3代人脐静脉内皮细胞于载体的后弹力层面,体外培养7~10 d行细胞形态、密度、组织学和扫描电镜观察,待细胞与后弹力层面融合形成单层后,用于兔角膜移植。受眼:正常健康新西兰大白兔24只(24眼),实验组(人脐静脉内皮细胞移植组)12眼,对照组(单纯猪角膜深板层移植组)12眼,全角膜范围去除术眼内皮细胞,实施移植手术。结果:人脐静脉内皮细胞在猪后弹力膜/基质载体上贴附生长,形成紧密连接的单层,形态近似六角形,呈铺路石状分布,具有正常兔角膜内皮细胞的超微结构。术后8周实验组角膜基本透明,周边角膜略有水肿。对照组单纯猪角膜深板层移植后,移植角膜明显水肿、混浊。结论:以异种角膜后弹力膜/基质为载体培养的人脐静脉内皮细胞,行异种异体移植后,能够在活体上成活,并能维持角膜透明,具有正常角膜内皮细胞的生物学功能。深板层角膜内皮移植术是体外培养血管内皮细胞移植的一种有效术式。  相似文献   

19.
The tetraspans associate with a large number of surface molecules, including a subset of beta1 integrins and, indirectly through CD19, with the complement receptor CD21. To further characterize the tetraspan complexes we have raised and selected monoclonal antibodies (mAb) for their ability to immunoprecipitate a molecule associated with CD9. A unique mAb was identified which recognizes the complement regulator CD46 (membrane cofactor protein). CD46 associated in part with several tetranspans and with all beta1 integrins that were tested (CD29/CD49a, CD29/CD49b, CD29/CD49c, CD29/CD49e, CD29/CD49f) but not with beta4 integrins. These data, together with cross-linking experiments showing the existence in living cells of CD46/integrin complexes, suggest that CD46 associates directly with beta1 integrins and indirectly with tetraspans. CD46 also acts as a receptor for measles virus; however, mAb to various integrins and tetraspans did not modify the virus fusion entry step.  相似文献   

20.
伞枝犁头霉在体外诱导人血管内皮细胞凋亡   总被引:1,自引:1,他引:0  
目的 研究伞枝犁头霉对人脐静脉血管内皮细胞活性的影响及其机制.方法 采用锥虫蓝染色法分析不同时间段伞枝犁头霉对人血管内皮细胞存活率的影响.细胞凋亡检测试剂盒在荧光显微镜下分析伞枝犁头霉诱导人血管内皮细胞的凋亡情况.流式细胞仪定量检测伞枝犁头霉诱导人血管内皮细胞在不同时间段的凋亡情况,并观察caspase-3抑制剂对凋亡反应的影响.用Western blot法检测伞枝犁头霉引发人血管内皮细胞caspase-3在不同时间段活化情况.结果 锥虫蓝染色法显示伞枝犁头霉以时间依赖的方式抑制人血管内皮细胞的存活率.伞枝犁头霉在共培养第12小时开始抑制人血管内皮细胞存活率(P=0.001).荧光显微镜显示伞枝犁头霉诱导人血管内皮细胞发生凋亡,而并非坏死.流式细胞仪分析显示伞枝犁头霉以时间依赖的方式诱导人血管内皮细胞发生凋亡反应.凋亡细胞在共培养第12小时显著增高(P=0.0036).Caspase-3抑制剂几乎可以完全逆转伞枝犁头霉诱导的凋亡反应.Western blot法显示伞枝犁头霉引起人血管内皮细胞caspase-3活化随时间逐渐增强.结论 伞枝犁头霉在体外试验中可以诱导人血管内皮细胞发生凋亡.该凋亡信号的传导是通过caspase级联反应.  相似文献   

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