病毒感染与自身免疫病

病毒感染与自身免疫病,Virus Infections and autoimmunity Exogenous viruses: EBV Molecular mechanism for autoimmunityEnogenous viruses : HERVAutoimmune disease: A role for new anti-viral therapies?,Outline,Virus Infections and autoimmunity (Background),自身免疫是机体失去对自身抗原的免疫耐受自身免疫病因与发病机制十分复杂: 遗传背景，但环境因素和生活方式等的也有重要作用。研究表明：病毒和细菌等感染与自身免疫病的发生、发展密切关系。一些病毒感染可导致机体失去对自身抗原免疫耐受，因而诱发、促进或加重自身免疫病。已证明某些病毒感染与一些自身免疫病密切相关，并发现病毒与宿主细胞的某些基因或其蛋白分子之间存在着结构类似性，因而可发生交叉免疫反应性。这种分子模拟假说获动物实验的支持。,少数T细胞克隆逃 避阴性选择 进入外周,识别自身抗原,通过激活诱导细胞死亡（AICD) (FasL-Fas-凋亡）,部分T细胞克隆 逃避AICD,识别自身抗原,自身免疫病(AID),T细胞发育过程自身耐受形成及逃避机制,B细胞发育过程自身耐受形成及逃避机制,克隆清除 结合 克隆无能 克隆忽视,不结合 克隆发育成熟,激活,自身免疫病,自身免疫病,激活,B细胞,骨髓细胞表面抗原,HostMHCLoss of ToleranceImmune system defectsSusceptibility GenesEndogenous VirusesAutoimmune disease,Environment and autoimmunity,Chemical substances,Microbial Agents,drugs,UVB light,Vaccinestyphoid, influenza, meningococcal, tetanus toxoid, measles, mumps, and rubella,Diet/Nutrition,新西兰小鼠(NzB),自发产生抗DNA抗红细胞抗体,溶血性贫血狼疮性肾炎,自然发生,新西兰小鼠(NZW),不发生系统性红斑狼疮(SLE),NZB X NZW(F1) 杂交小鼠,抗DNA和其他核抗体与人类SLE类似,感染病毒,感染病毒,自身抗体效价更高自身免疫病的发生更早,发生自身免疫病,These observations lend further support that both genetic and environmental factors play a role in autoimmune disease.,Exogenous viruses,Exogenous microbial agents, such as bacteria or viruses, interact with and sometimes might override the human immune system to cause infectious diseases, cancers and autoimmunity.,Exogenous viral agents have also been implicated as potential triggers or pathogenic agents of autoimmune conditions. Viruses which have been linked to the pathogenesis of SLE include ： Epstein-Barr Virus (EBV) Cytomegalovirus (CMV), parvovirus (细小) B19 Human Papilloma Virus (HPV), Human Herpes Virus (HHV-6), HHV-7, HHV-8, Dengue virus HIV human T cell lymphotropic virus (HTLV,人类嗜T细胞病毒 ),EBV as a potential viral agent in SLE,In SLE, EBV has been highlighted as a potential pathogenic agent through serological studies of patients that have shown antibodies to early antigens, capsid and latent membrane proteins in much higher frequency as compared to controlsin pediatric SLE, 99% of patients are anti-EBV Ab+ compared to 70% of controlsIn people with SLE, the number of EBV infected B cells is elevated 10 to 100 times over the levels in controls, and the amount of free virus in serum is also elevated.molecular analysis of complementary EBV transcripts appears to substantiate these observationIncreased virus levels are associated with disease flares LMP1 mRNA is the most frequently detected latent EBV product in the blood of SLE patientsa meta-analysis of serological studies revealed that antibodies to capsid and early antigen proteins were particularly prominent.EBV is recognized as a strong polyclonal B cell activator and therefore could stimulate a substantial number of potentially autoreactive B cells.,EBV 结构和蛋白,（Epstein-Barr virus，EBV）,Epstein和Barr：1964年首次成功地在Burkitt非洲儿童淋巴瘤细胞中发现,靶细胞： B细胞、鼻咽上皮细胞、胃上皮感染类型： 潜伏感染 核抗原（EBNA），潜伏膜蛋白（LMP） 增殖感染 早期蛋白（EA）， 病毒衣壳抗原（VCA） 膜抗原（MA）,受体：CD21分子,增殖性感染表达的抗原,当EBV进入宿主细胞后，首先表达反式激活蛋白ZERBA，进而激活EBV早期基因，产生增殖性感染。 EBV早期抗原(early antigen, EA) ：增殖早期诱导的非结构蛋白，分为 EA-R：存在于细胞浆中 EA-D：存在于细胞浆和细胞核内，并具有EBV特异的DNA多聚酶活性。 EA：表示EBV增殖活跃，是感染细胞进入溶解性周期的标志。 非洲儿童恶性淋巴瘤患者抗EA-R抗体阳性，鼻咽癌患者抗EA-D抗体阳性。EBV衣壳抗原(viral capsid antigen, VCA) : 病毒增殖晚期合成的结构蛋白，存在于细胞浆和细胞核内。 VCA: 与病毒DNA组成EBV的核衣壳，在核膜出芽时获得包膜装配成完整病毒体。 VCA-IgM: 出现早，消失快，VCA-IgG:出现晚，持续时间长。EBV膜抗原(membrance antigen, MA) 存在于细胞表面，为包膜糖蛋白，其中 糖蛋白gp320/220能诱导产生中和抗体。 MA-IgM: 用于早期诊断，MA-IgG: 可体内持续存在。,潜伏性感染表达的抗原,EBV在记忆B细胞及某些上皮细胞中可表现为潜伏感染，仅部分表达基因发生转录， 选择性表达EBV潜伏感染期蛋白。 EBV核抗原（EB nuclear antigen, EBNA）: DNA结合蛋白，所有EBV感染 和转化的B细胞核内均可检出该抗原。 (EBNA1, -2, -3A, -3B, and -3C) EBNA-1: 与EBV基因组以环状附加体(episome)形式持续存在，对细 胞处理和抗原提呈功能具有抑制作用，从而逃避宿主细胞的 CTL杀伤作用，因此与维持EBV基因组在感染细胞内潜伏有关； EBNA-2和EBNA-3为转录因子: 可调控多种病毒蛋白和宿主细胞蛋白的表 达，与诱导B细胞转化有关。潜伏感染膜蛋白(latent membrance protein, LMP) : 存在于潜伏感染B细胞表面，有LMP-1和LMP-2 (LMP2A,LMP2B)两种。 LMP-1: 功能类似活化的生长因子受体，能与细胞抑癌蛋白（肿瘤坏死因子受体相关 因子，TRAF）相互作用，抑制细胞凋亡，诱导B细胞转化，是一种致癌蛋白； LMP-2: 细胞酪氨酸激酶的底物，具有阻止潜伏病毒激活的作用。,Gp350-CD21,BMRF2-1整合素,gp110-?,Immunological Mechanisms for Autoimmunity,Molecular MimicryBystander Activation and Epitope Spreading Polyspecific B-cell Activation Accumulation of EBV-specific CD8+ T-cells in Sites of Inflammation Transactivation of Human Endogenous Retroviruses （反式激活）,Molecular mimicry,Sequence or structural similarities between microbial and self-antigens are believed to cause cross-reactivity of T-cells, B-cells and antibodies,EBNA-1,In SLE, autoantibodies against epitopes on SmBB and SmD have been shown to cross-react with different domains of EBNA-1 EBNA-1 motif PPPGRRP (aa 398404) - Rabbits immunized - lupus-like autoimmune disease EBNA-1 full length protein -mice immunized -anti-dsDNA and anti-Sm antibodiesRo (aa 169180) -autoantibodies - SLE EBNA-1 (aa 5872)-,cross-reaction,李玲玲，朱珊丽，李文姝，薛向阳，张丽芳* EBV核蛋白-1B细胞表位的预测及其同源性分析 生物医学工程学杂志 2011，28（2）：371-375,LMP1,LMP1 expression has been implicated in making important contributions to a variety of human malignancies, as well as to autoimmune diseases.LMP1 alters B-cell biology and the molecular mechanisms by which it exerts these effects by LMP1-mediated signaling pathways,Fig. 1. Activation of cell signalling pathways by LMP1. The carboxyl terminus of LMP1 contains three signalling domains, termed CTAR1, CTAR2 and CTAR3, which recruit TNFR-associated signalling adapter proteins (TRAF, TRADD, RIP), BS69 and Janus kinase (JAK)-3 proteins. These activate the NF-B, JNK/SAPK, PI3-K/Akt, ERK-MAPK, PLC/PKC and JAK/STAT signalling pathways, which collectively induce the expression of numerous downstream effectors that impact on a variety of cellular processes such as proliferation, survival, motility and invasion. 187-386: 200个氨基酸残基为C端胞浆区，含活性区域1-3（CTAR1，2，3）,IFNIL-6IL-10,IFN- play an important rolein SLE pathogenesis. (development of the inflammatory),in the,Bystander Activation（旁路激活）,Bystander activation ：lymphocytes are stimulated by cytokines or superantigens, or antigen-dependent in the setting of tissue destruction and presentation of self-antigens by APC to autoreactive T- or B-cells,（T细胞表位不同，无Th活化信号）,Epitope Spreading（表位扩展）,抗原刺激免疫系统，首先针对免疫优势表位产生免疫应答，如果抗原没有及时清除，免疫应答持续时，机体可相继针对隐蔽表位产生应答-表位扩展。,Polyspecific B-cell Activation,（非特异性激活）,Accumulation of EBV-specific CD8+ T-cells in Sites of Inflammation,EBV specific CD8+ T-cells are enriched in or near the diseased organs of patients with RA and MS . EBV-specific CD8+ T-cells have also been reported to accumulate in synovial fluid (滑液)from patients with psoriatic arthritis, osteoarthritis and Reiters syndrome局部炎症部位EBV特异性CTL细胞的集聚，加剧了局部的炎症反应,Transactivation of Human Endogenous Retroviruses,EBV 诱导内源性逆转录病毒-产生 HERV-K18HERV-K18编码-超抗原-激活- T细胞 HERV-K18表达产物-在RA的外周血和关节液中出现 ，但SLE尚未报道。 已经证明EBV 在体外可激活-HERV-W（MS相关逆转录病毒（MSRV），在MS患者的星形胶质细胞，B细胞和单核细胞中存在MSRVMSRV 体内外均可激活T-cells 并诱导产生 cytokines.,Enogenous viruses : Human Endogenous Retroviruses （HERV）,HERV是几百万年前整合到人类基因组中，并以孟德尔方式遗传至今的逆转录病毒的残余物，约占了人类基因组DNA的8HERV可以通过转座作用而增加其在基因组中的拷贝数，因此有些家族的成员数达上千个，现已发现的HERV家族至少有31个。HERV数量虽多，但大部分由于突变、缺失等的积累，已经没有编码能力。HERV各家族基因结构基本相同，但许多功能都不明确，过去大多数研究人员将内源性逆转录病毒视为垃圾DNA。,Human Endogenous Retroviruses （HERV）,随着研究的深人，人们发现少部分HERV保留了产生逆转录病毒产物和病毒颗粒的能力HERV与人类的进化关系密切，是哺乳动物生殖所必需的，并且影响哺乳动物胎盘发育，是妊娠所不可或缺的基因。同时和胎盘共同构建了一个防止微生物感染胎盘的屏障。HERV还参与人体多种自身免疫性疾病和肿瘤的发生和发展过程。 HERV抗体在睾丸肿瘤、乳癌和黑素瘤中很常见。,几百万年前，HERV感染人类的生殖细胞，从而成为宿主遗传基因组的一部分。遗传给宿主的子孙后代。,整合在人类基因组中的内源性逆转录病毒无法从宿主的DNA上转录。,Schematic representation of HERV-K10. Insert: electron micrograph (magnification: 15,000) of HERV-K particles budding from a teratocarcinoma（畸胎瘤） cell line TERA-1.,HERVs,Class I HERVs: HRES-1， (HERV-R) ERV-3 HERV-E 4-1Class II HERVs: HERV-K10， HERV-K18Class III :,HRES-1,two Gag-related products : 28-kD nuclear autoantigen (p28) ： HRES-1/p28 24-kD small GTP-ase (termed HRES-1/Rab4)higher titres of autoantibodies to HRES-1/p28 nuclear protein or synthetic peptides in patients with SLEMolecular mimicry may be responsible in generating cross-reactive ： HRES-1/p28 and the 70-kD spliceome protein U1 snRNP.In lupus patients：CD4 + T cells appear to over-express HRES-1/Rab4， which regulates the CD4.Thus, Gag-related products could play a significant role in modulating B and T cell reactivity in SLE,Figure 3 (a) Molecular models of a homologous epitopes located on SmD1 and HRES-1. (b) Amino acid sequence homology between HRES-1 gag and SLE autoantigens.,ERV-3，HERV-E 4-1,ERV-3 Env and several SLE autoantigens, Ribosomal-P,Ro/SS-A-ribo nuclear protein and Beta-2-glycoprotein：共同抗原Beta-2-glycoprotein is associated with anti-phospholipid syndrome（抗磷脂综合征）, whilst Ribosomal-P （核糖体磷脂）antibodies are strongly associated with SLE, as demonstrated in a mouse model.Peripheral blood mononuclear cells derived from SLE patients generate mRNA gag transcripts of HERV-E 4-1,HERV K10,Serum antibodies from SLE patients have also demonstrated to an envelope derived peptide of HERV K10Herpes viruses such as EBV and CMV have been shown to influence HERV-K10 activity and upregulate HERV transcriptionEBV gene products, EBNA-1, Latent Membrane Protein (LMP1) and LMP2A, significantly enhance HERV-K10 transcripts.,HERV与系统性红斑狼疮的关系,在系统性红斑狼疮患者的器官和血清中发现了HERV成分的抗原及相应 的抗体， 电镜观察系统性红斑狼疮患者的组织，发现了逆转录病毒颗粒HRES-1, ERV-3, HERV-E 4-1, HERV-K10 and HERV-K18 have also been implicated in SLE.在体外实验中HERV逆转录病毒成分可以诱导出系统性红斑狼疮样的免疫异常合成的HERV E 4-1来源的多肽P15E (env序列编码的跨膜蛋白)，能 够诱导许多免疫异常，如CD4+ T细胞的活化和失能，细胞因子的产生(如IL-6、IL-16)和细胞因子相关的多克隆B细胞活化。近来有研究者报道，在系统性红斑狼疮患者中HERV E 4-1序列比正 常对照组转录明显增加，大约有50 的患者血清中发现能与其转录产物结合的抗体，而对照组是零 。,HERV与类风湿性关节炎的关系,与健康对照人群或者骨关节炎患者相比，类风湿性关节炎患者的HERV-K10 mRNA表达增加，提示HERVK10可能与这种自身免疫性疾病的致病性有关研究结果显示，68 的类风湿性关节炎患者的外周血中单核细胞中HERV-K10 mRNA表达水平增加，骨关节炎患者为l7 ，对照组为185。在类风湿性关节炎患者中HERV增加可能与宿主蛋白的分子模拟相关，或由环境因素触发激活了HERVs。含活化HERV的宿主细胞移行到滑膜并产生促炎细胞因子，诱导RA疾病的发生。,HERV与多发性硬化症的关系,1997年，发现多发性硬化症(MS)患者细胞培养过程中产生了 第一个HERV逆转录病毒颗粒：Ms相关逆转录病毒(multiple sclesis associated retrovirus，MSRV)- HERV-W 家族。用免疫组化法对HERV-W家族检测：在健康人脑的神经细胞中有HERV-W 的Gag蛋白的生理