补体在单克隆抗体介导的肿瘤免疫治疗中的作用

被单克隆抗体激活的补体可以直接造成肿瘤细胞溶解或增强ADCC作用。然而肿瘤细胞表面通常有高水平表达的膜结合补体调节蛋白（mCRP）使其免受补体介导的杀伤作用。近期研究表明,阻断或克服肿瘤细胞的mCRP可显著提高单抗免疫治疗的疗效。另外,单抗辅以β-葡聚糖可以使iC3b沉积在肿瘤细胞表面并激活补体受体3（CR3）从而介导CR3依赖性细胞毒作用。这些都已成为现有单抗作用机制的有益补充。     

补体攻膜复合物与肾小球疾病

MAC是补体活化后产生的效应单位 ,补体激活可通过抑制免疫复合物网络形成 ,产生过敏毒素 ,协助免疫复合物从肾小球毛细血管内皮下转移至上皮下 ,它可直接或间接作用肾小球细胞而致损伤 ,MAC在肾小球疾病中的作用一直引起众学者的关注。本文就MAC形成、作用机制与肾小球细胞损伤的关系进行综述。1　MAC的形成抗原与抗体形成免疫复合物可激活补体经典途径 ,内毒素、G-菌、IgA可激活旁路途径 ,两条补体激活途径形成C5转化酶 C4b2a3b ,C3bBb3b ,然后裂解C5 ,并与C6、C7、C8、C9形成末端补体复合物 (terminalcomplementcomplex ,TCC)…     

红细胞CR1与疾病关系研究进展

CR1(complement receptor 1/C3bR/C4bR)是一种多形性单链膜结合蛋白,由细胞外、跨膜、细胞内三部分组成,在多种细胞表面均有表达。CR1是C3b及C4b的受体,在清除与C3b和C4b结合的免疫复合物中有重要意义。红细胞上CR1(E-CR1)参与多种自身免疫性疾病及感染性疾病的发病机理。     

C3d及荷C3d免疫复合物的测定与意义

补体在激活剂(activators)如抗原抗体复合物(IC)、C-反应蛋白、葡萄球菌A蛋白、聚合阴离子(polyanions)以及某些细菌、病毒激活下,可经传统或旁路途径活化。C3被C3转化酶(C-42,C——3bBb)裂解成C3a、C3b片段,在H因子协同下,C3b进一步被I因子裂解成C3c、C3f、C3dg,后者又被蛋白水解酶水解成C3d、C3g。血清中C3d含量可反映补体活化程度。由于补体被IC激活后,C3d可以共价键结合于IC上,因而IC上荷有C3d是该种IC可激活补体的标志。鉴于补体的活化,IC特别是激活补体的IC在组织中的沉着具有重要的病理生理意义,并在某些疾病的发病机…     

CR3/MAC-1对髓鞘吞噬作用的调节

外周神经轴突发生华勒变性时,小胶质细胞和巨噬细胞能够有效地清除髓鞘,但这一作用在中枢神经轴突损伤时不明显。中枢神经系统小胶质细胞可表达CR3／MAC-1整合素(complement-receptor-3 integrin),这种整合素具有潜在的介导髓鞘吞噬的功能。由此我们推测, CR3／MAC-1可能存在着活化和失活两种状态,分别决定髓鞘吞噬的有效和无效。CR3／MAC-1介导的髓鞘吞噬调节机制可能有:1、活化的补体系统促进CR3／MAC-1介导的髓鞘吞噬;2、抗αM单克隆抗体对CR3／MAC-1介导的髓鞘吞噬起抑制作用,而抗β2单克隆抗体则起促进作用;3、活化的补体系统可以影响单克隆抗体对CR3／MAC-1介导的髓鞘吞噬的调节作用。     

异种抗体IgM对培养豚鼠心脏微血管内皮细胞的作用

目的:了解大鼠体内天然抗体IgM在非协调性异种心脏移植超急性排斥反应中的作用。方法:以培养豚鼠心脏微血管内皮细胞为异种心脏移植的细胞实验模型,通过补体结合实验、免疫组化等方法研究大鼠抗体IgM对该细胞的作用,了解异种抗体IgM在异种移植超急性排斥反应中的作用机制。结果:在该模型中,大鼠抗体IgM可与豚鼠心脏微血管内皮细胞结合并能激活补体,产生对该细胞的损伤,而经小鼠抗大鼠IgM处理后的大鼠血清,对豚鼠心脏微血管内皮细胞的损伤作用明显减轻。结论:在该实验模型中,异种天然抗体IgM是激活补体引起超急性排斥反应的重要因素。     

免疫学知识介绍(六)

三、补体的生物学活性: 补体系统是非特异性免疫的重要因素之一,它的作用是多方面的,既参与机体的免疫应答反应和自身稳定功能,也可引起免疫病理的损害。补体系统被激活进行至最后阶段损伤靶细胞则表现出重要的生物学作用。如果靶细胞是细菌,则细菌溶解,机体可以不被感染;若靶细胞是自身细胞,则自身组织被破坏,引起自身免疫反应成为病变。除损伤靶细胞外,补体激活过程中产生的各种生物学活性物质对机体也有重要意义,具体分述如下: (一)免疫粘连和调理作用——促进吞噬: 免疫粘连是补体系统重要的生物活性之一。免疫粘连是指抗原与微量抗体结合时吸附补体C_(1423)     

多糖类药物作用的受体及信号转导机制的研究进展

β-葡聚糖通过补体3型受体(CR3)增强巨噬细胞、NK细胞、中性粒细胞的杀伤作用;多数多糖可通过Toll样受体4(TLR4)或TLR2激活和增强巨噬细胞的吞噬功能,或诱导巨噬细胞合成包括肿瘤坏死因子α(TNF-α)在内的多种细胞因子;也有报道β-葡聚糖的主要受体是树突状细胞相关C型凝集素-1(dectin-1),而且介导了巨噬细胞的生物功能。     

DFMG拮抗LPC诱导主动脉内皮细胞凋亡

目的 研究7-二氟甲氧基-5、4'-二甲氧基金雀异黄素(7-difuoromethoxy-5,4'-dimethoxy-genistein,DFMG)对溶血性磷脂酰胆碱(lysophosphatidylcholine,LPC)诱导人主动脉内皮细胞(human aorta endothelial cells,HAEC)凋亡的影响.方法 体外培养HAEC.Annexin V/PI染色流式细胞术(FCM)分析细胞凋亡率.ELISA法测定Caspase-3、8和9活性.Western blotting分析细胞色素c和死亡受体-4、-5表达.结果 LPC(10μmol/L)处理HAEC 24 h,细胞凋亡率为(31.6%±4.1%)(P＜0.001).DFMG预孵育降低LPC诱导HAEC细胞凋亡率,Caspase-3、-8和-9活化及细胞色素C和死亡受体-5表达(P＜0.05).结论 DFMG拮抗LPC诱导HAEC细胞凋亡作用与阻断LPC激活死亡受体和线粒体凋亡途径有关.     

高糖和MBL共培养的人肾小球内皮细胞替代途径补体激活发病机制探讨

目的采用高糖和甘露聚糖结合凝集素（MBL）共同培养人肾小球内皮细胞（HRGEC）,探讨糖尿病肾病是否存在替代途径补体激活发病机制。方法体外培养正常HRGEC,随机分为单纯高糖组和高糖＋MBL组,两组分别用30mmol/L D-葡萄糖培养72h后,加入等量30%MBL缺乏人血清,高糖＋MBL组另外加入10μg/mL MBL,继续培养4h。采用流式细胞技术观察细胞表面MBL-C 3bBb的沉积,采用免疫荧光染色观察补体激活产物膜攻击复合物（MAC）的沉积。结果流式细胞技术证实,高糖＋MBL组细胞表面有明显的MBL和C 3bBb共沉积,免疫荧光染色显示该组细胞表面有明显MAC沉积,单纯高糖组无上述现象。结论高糖和MBL共同存在时发生MBL补体途径激活,并启动补体的替代途径,DN发病可能与上述两条补体途径激活有关。     

Two conformational forms of target-bound iC3b that distinctively bind complement receptors 1 and 2 and two specific monoclonal antibodies

Introduction

The complement system is an essential part of the immune system of vertebrates. The central event of the complement activation cascade is the sequential proteolytic activation of C3, which is associated with profound alterations in the molecule''s structure and conformation and is responsible for triggering most of the biological effects of complement.

Material and methods

Here, we have studied the conformation of C3 fragments deposited onto an IgG-coated surface from human serum during complement activation, using a set of unique monoclonal antibodies (mAbs) that are all specific for the C3dg portion of bound iC3b.

Results

We were able to identify two conformational forms of target-bound iC3b: the first recognized by mAb 7D18.1, and the second by mAb 7D323.1. The first species of iC3b bound recombinant complement receptor 1 (CR1), while the second bound CR2. Since CR1 and CR2 are expressed by different subsets of leukocytes, this difference in receptor-binding capacity implies that there is a biological difference between the two forms of surface-bound iC3b.

Conclusion

We propose that mAbs 7D18.1 and 7D323.1 can act as surrogate markers for CR1 and CR2, respectively, and that they may be useful tools for studying the immune complexes that are generated in various autoimmune diseases.     

热休克蛋白60在多西紫杉醇治疗激素非依赖性前列腺癌过程中的差异表达

目的 分别比较热休克蛋白60(HSP60)在多西紫杉醇(Docetaxel)诱导前列腺癌PC-3细胞凋亡及耐药前后表达的差异,并探讨其意义。方法 采用20μmol/L Docetaxel诱导PC-3细胞凋亡,后采用逐渐加量的方式培养PC-3细胞Docetaxel耐药株;采用双向荧光差异凝胶电泳(DIGE)技术定量筛选未处理组PC-3细胞与凋亡PC-3细胞,及PC-3细胞敏感株与耐药株的差异蛋白,并采用基质辅助激光解吸电离飞行时间质谱(MALDI-TOF-MS)技术对其进行成分鉴定,进而检测HSP60的表达。结果 HSP60在Docetaxel诱导PC-3凋亡细胞中表达上调,在Docetaxel耐药株中表达下调。结论 HSP60在PC-3凋亡细胞中高表达,在Docetaxel耐药株中的低表达,提示其可能与PC-3细胞的凋亡及耐药有重要关系。     

Opsonic requirements for the respiratory burst of neutrophils against Giardia lamblia trophozoites

BACKGROUND: Giardia lamblia is an important cause of parasitic diarrheal disease worldwide. Occasionally, polymorphonuclear neutrophils (PMNs) may participate as effector cells against Giardia lamblia. The present study was performed in order to examine the role of specific antibody and complement components in promoting the respiratory burst (RB) of PMNs against Giardia lamblia. METHODS: PMNs from human adult volunteers were incubated with Giardia trophozoites in the presence of non-immune (NS) or hyperimmune (HS) serum (anti-Giardia titer, >1:1024). Adherence was scored visually on coverslide after staining with Giemsa. The ability of Giardia to trigger the oxidative response of PMNs was measured by the anion superoxide (O2(-)) production using a cytochrome C reduction method and by the luminol amplified chemiluminescence (CL) assay. RESULTS: Incubation with NS or HS increased Giardia adherence to PMNs from 6.9 +/- 3.2% (basal adherence of Giardia incubated in buffer) to 39 +/- 18.6% (p <0.01) and 76 +/- 19.5% (p <0.001), respectively. In absence of serum, Giardia failed to trigger an oxidative response of PMNs. Opsonization with NS or HS increased the PMN O2(-) production from 3.9 +/- 0.92 nmol/2.5 x 10(6) PMNs/10 min to 9.04 +/- 1.68 (p <0.05) and 17.9 +/- 1.32 (p <0.001), respectively. A similar enhancement of the CL response was also observed. The inactivation of complement activity by heat as well as the elimination of specific antibodies by absorption produced a significant abrogation of the oxidative response but in the case of HS heat inactivation alone did not abolish the response. Similar findings (variable abrogation of the oxidative PMN response) were observed when PMNs were incubated with monoclonal antibodies directed against complement C3, C3b or the low-affinity Fc receptors (CR1, CR3 or FcRlo). CONCLUSIONS: These results show that complement components and specific antibodies influence in the Giardia-PMN interaction. Although components of complement can contribute to the RB of PMNs, specific antibodies are critical for an optimal oxidative PMN response.     

高血糖对卵母细胞和早期胚胎细胞凋亡的影响

妊娠糖尿病妇女流产、畸胎等并发症与高糖环境下卵母细胞、早期胚胎细胞凋亡密切相关。高血糖能通过死亡受体途径诱发卵母细胞凋亡,细胞间缝隙连接蛋白Connexin-43表达减少与颗粒细胞凋亡密切相关;高血糖还能通过线粒体途径诱导早期胚胎细胞凋亡,Bax、Bcl-2、p53等基因的调控在其中扮演重要角色。葡萄糖转运子表达减少是着床前胚胎细胞凋亡的始发因素,而氧化应激则与着床后早期胚胎细胞凋亡机制相关联。     

IgA肾病中补体系统及肾小球肥大对足细胞的损伤

目的探讨IgA肾病中补体系统及肾小球体积改变对足细胞的损伤。方法采用免疫组化方法观察IgA肾病患者肾小球内WT1、C5b-9、CR1表达的改变,免疫荧光观察C3染色及laminin-C5b-9双染。采用肾小球体视学研究方法观察IgA肾病患者的系膜区/毛细血管襻点密度比、肾小球体积、肾小球毛细血管襻表面积。结果IgA肾病患者肾小球内WT1阳性细胞数明显减少。IgA肾病肾小球内存在C3的明显沉积,与WT1阳性细胞数呈明显负相关,CR1的表达减少并与WT1阳性细胞数呈正相关趋势。肾小球内明显伴有C5b-9的沉积,并证实确实攻击足细胞,C5b-9的沉积与WT1阳性细胞数和CR1均呈明显负相关。IgA肾病患者存在明显的系膜区扩张、小球体积肥大,系膜区的扩张和小球体积肥大呈明显正相关。结论IgA肾病中确实存在足细胞数目的减少。同时,补体系统及系膜区的扩张所导致的肾小球体积的增加可能参与了IgA肾病中足细胞的损伤。     

Toll样受体在胎盘中的表达研究

Toll样受体(TLRs)是近几年发现的天然免疫受体,它们能特异性地识别病原微生物的结构成分,激活天然免疫。目前已克隆鉴定出13种TLR,其中TLR1~10在胎盘中有表达,表明TLRs在胎盘的先天性免疫过程中可能起重要作用。     

CR1在红细胞免疫中的研究进展

目的总结Ⅰ型补体受体(CR1,CD35)在红细胞免疫中的研究进展。方法通过阅读有关文献,了解红细胞CR1在红细胞免疫研究中的地位。结果CR1分子有其特定的编码基因、分子结构、生物学特性,广泛参与体内免疫复合物(IC)的清除。结论CR1是红细胞执行免疫功能的主要分子基础。     

Role of CX3CL1 in the chemotactic migration of all-trans retinoic acid-treated acute promyelocytic leukemic cells toward apoptotic cells

BackgroundPhagocytic clearance of apoptotic neutrophils by tissue macrophages is a crucial component in the resolution phase of acute inflammation. However, the number of tissue macrophages is low and not likely to cope satisfactorily with the excess number of dying neutrophils. Although recent studies have reported that neutrophils are able to engulf apoptotic neutrophils, the mechanisms by which living neutrophils are attracted to apoptotic neutrophils are poorly defined. Increased amounts of CX3CL1 and microparticles (MPs) are rapidly released by apoptotic cells, and are involved in the chemoattraction of mononuclear phagocytes toward apoptotic cells. The current study investigated the role of CX3CL1 in the chemoattraction of all-trans retinoic acid (ATRA)-treated NB4 (ATRA-NB4) cells toward apoptotic cells.MethodsConditioning medium and MPs were harvested from apoptotic ATRA-NB4 cell cultures to determine their effects on living ATRA-NB4 cells by transmigration assay and adhesion assay. The cytokine levels in the conditioning medium were determined by enzyme-linked immunosorbent assay. Expression of CX3CR1 (a receptor of CX3CL1) on ATRA-NB4 cells was determined by flow cytometric analysis.ResultsATRA-NB4 cells transmigrated toward the apoptotic ATRA-NB4 cells, and this chemoattraction was partially inhibited when the CX3CR1 on ATRA-NB4 cells was blocked by its specific antibody. Both exogenous CX3CL1 and MPs released by apoptotic ATRA-NB4 cells were able to enhance the chemoattraction of ATRA-NB4 cells toward apoptotic cells or the adhesion of ATRA-NB4 cells to endothelial cells. CX3CL1 was expressed on the surface of MPs, and blocking this CX3CL1 with its specific antibody was able to partially inhibit the chemoattractive property of MPs.ConclusionCX3CL1, in either the free or MP form, is released rapidly by apoptotic ATRA-NB4 cells after induction of apoptosis to mediate the chemoattraction of living ATRA-NB4 cells toward apoptotic cells.     

补体因子H与心血管疾病的研究进展

心血管疾病严重威胁人类健康，具有高发病率、高致死率和高致残率的特点。近年来研究发现，补体因子H（complement factor H，CFH）是补体系统和炎症反应中非常重要的负性调节因子。CFH的减少或缺如可使补体旁路途径持续激活及介导的炎症反应增强，导致血管内皮细胞和心肌细胞等损伤。CFH在心血管疾病的发病中扮演着重要的角色并参与了其病理生理学机制。现系统综述CFH在心血管疾病发病中的作用及机制。     

胰腺癌细胞与其基质成纤维细胞相互影响的研究

目的：观察胰腺癌细胞系BXPC-3、SW1990能否促进其基质中正常成纤维细胞( NFs)活化成癌相关成纤维细胞( CAFs)及其活化的可能机制,以及活化后的CAFs对BXPC-3、SW1990细胞迁移能力的影响。方法采用差异贴壁法分选出野生型小鼠C57胰腺组织中的NFs,后运用非接触式共培养方法将BXPC-3、SW1990与NFs共培养,共培养后采用免疫荧光方法检测共培养前后NFs中CAFs标志性蛋白α-平滑肌肌动蛋白(α-SMA)、成纤维细胞活化蛋白( FAP)的表达变化,以确定其是否活化,并且运用qRT-PCR法检测目前较公认的胰腺癌中升高的12种 miRNAs 在共培养前后的NFs中含量变化；采用 transwell 法观察活化前后的 NFs 对BXPC-3、SW1990迁移能力的影响。结果免疫荧光检测表明,与BXPC-3、SW1990共培养后, NFs中α-SMA、FAP表达均显著升高；同时,在所选取的12种miRNAs中,与BXPC-3、SW1990共培养后,NFs中miR-155含量均有明显升高。 BX-PC-3、SW1990在CAFs基质环境中迁移能力大大提高。结论胰腺癌细胞能够促进其周围NFs活化成CAFs,其活化可能与胰腺癌中某些特定的 miRNA分泌进入到 NFs中有关,活化后的CAFs又可以反过来促进胰腺癌细胞的迁移。