肿瘤免疫071103

immunology,肿瘤免疫Cancer and the immune system,邱双健,复旦大学中山医院肝癌研究所、肝外科,1901年以来，免疫学领域研究中有19项获得Nobel奖 例如: 人类血型的发现 (1930) 移植免疫 (1991),immunology,The immune system,Immune system,解剖屏障( 皮肤、粘膜等) 生理屏障 (温度, pH) 吞噬屏障 (细胞吞噬外来分子) 炎症屏障 (红、肿、热、痛),抗原特异性多样性 免疫记忆自身/非自身抗原识别,immunology,T cells,两种类型:Helper T cells (Th): activates other cellsCytotoxic T cells (Tc): can kill other cellsT 细胞识别抗原需有MHC分子的参与,immunology,Presentation of antigens to T cells,Proteins (peptides) from inside the cell are presented by MHC I molecules to Tc cells.Proteins (peptides) from the outside of cells are presented by MHC II molecules to Th cells.MHC I on almost all cellsMHC II on specialized antigen-presenting cells,immunology,T 细胞的抗肿瘤作用,双重激活信号第一信号：APC细胞的递呈及TCR复合物的形成第二信号：APC共刺激因子（B7、粘附分子等）参与第一信号中，T细胞活化受MHC分子限制 - MHC-类分子递呈内源性抗原，激活CD8+T 细胞 - MHC-类分子递呈外源性抗原，激活CD4+T细胞,immunology,T 细胞的抗肿瘤作用,活化的CD8+T细胞（CTL）是主要的效应细胞CTL分泌释放多种细胞因子及酶表达FasL，于Fas结合，诱导肿瘤细胞凋亡活化的CD4+T细胞通过分泌细胞因子来激活和增强CTL、NK、巨噬细胞的杀瘤效应少数CD4+T细胞也具有直接杀伤肿瘤细胞作用,immunology,Th,Tc,病毒感染细胞、肿瘤细胞,抗原递呈细胞,MHC II + peptide,MHC I + peptide,immunology,NK细胞的抗肿瘤作用,NK细胞不需致敏即可杀伤多种肿瘤细胞及病毒感染细胞对肿瘤细胞的杀伤不要表现为直接溶解细胞和分泌细胞因子两方面一些肿瘤细胞对NK细胞杀伤的敏感性与存在于肿瘤的MHC分子的变化有关,immunology,巨噬细胞的抗肿瘤作用,作为效应细胞通过非特异性吞噬作用杀伤细胞通过分泌多种细胞毒效应分子直接或间接抑瘤或杀瘤：No、IL-1、TNF、IFN等作为抗原递呈细胞，激发特异性T细胞免疫,immunology,NKT 细胞的抗肿瘤作用,既表达T细胞的表型标记（CD3、TCR)又表达NK细胞的表型标记（CD56)NKT细胞识别的是类似于类MHC的单态性抗原近年的研究表明NKT细胞是肿瘤免疫的执行者，在机体免疫自稳和肿瘤免疫方面有重要意义,immunology,树突状细胞的作用,很少量DC可以激发强大的T细胞反应可以激活静息T细胞，这种作用与DC-SIGN分子有关体内可以致敏CD4+T辅助细胞和CD8+T杀伤细胞,immunology,Cancer,The second ranking cause of death after heart disease in the Western world. most organs and tissues in an organism are in balance (death and renewal) cancer cells have no control in growth mechanisms, can expand to a large size producing a tumor,immunology,Tumor growth and metastasis,immunology,免疫缺陷与癌症的发生密切相关,肿瘤刺激机体的免疫应答,动物可对肿瘤产生免疫免疫力可转移给其他动物在患有一些恶性肿瘤的人体，已经能检测到肿瘤特异性抗体和细胞,抗肿瘤免疫机制,Immune system,补体的溶细胞效应 CDC效应抗体依赖的细胞介导的细胞毒效应 ADCC效应抗体的免疫调理作用抗体对肿瘤细胞的封闭作用抗体干扰肿瘤细胞的黏附作用,T细胞的抗肿瘤作用 主要是细胞毒性T淋巴细胞NK细胞的抗肿瘤作用巨噬细胞的抗肿瘤作用 作为效应细胞通过非特异性吞噬作用 通过分泌多种细胞毒效应分子起作用 作为抗原递呈细胞NKT细胞 同时有T、NK细胞表型树突状细胞,immunology,肿瘤抗原,两种类型:肿瘤相关抗原（TAA、TATAs) 正常组织也有不同程度表达肿瘤特异性抗原（TSA、TSTAs) 仅仅表达于肿瘤细胞,immunology,肿瘤抗原的现代分类,immunology,寻找肿瘤特异性抗原,肿瘤细胞cDNA文库转染表达相应HLA分子的靶细胞肿瘤细胞表面分子或纯化的HLA分子洗脱肽反向免疫法寻找肿瘤细胞特异的高表达分子重组cDNA表达文库的血清学鉴定技术等蛋白组学高通量筛选技术,immunology,肿瘤免疫逃逸机制,被动机制肿瘤细胞表面MHC分子表达及抗原处理异常缺乏抗原性表位缺乏共刺激因子Fas/FasL系统的异常表达,immunology,肿瘤免疫逃逸机制,主动机制肿瘤组织产生免疫抑制因子T细胞的异常 消除肿瘤特异性T细胞 诱导免疫抑制功能T细胞产生 引起T细胞的耐受 引起TAA特异性的T细胞无能 抑制DC的分化、成熟 TCR及IL-2受体通路异常 CD4+/CD8+倒置和Th1/Th2飘移肿瘤抗原被封闭其他方面：膜结合补体调节蛋白、黏附分子缺失、癌基因过度表达等T调节细胞（CD4、CD25共表达T细胞）的增加,immunology,肿瘤的免疫治疗,主动免疫治疗,被动免疫治疗,肿瘤特异性抗原的应用,制备单克隆抗体用于诊断用于治疗在体内刺激特异性免疫应答特异性主动治疗特异性被动治疗,肿瘤特异性抗原制备的单克隆抗体的应用,单克隆抗体可作为诊断的工具,非特异性免疫治疗,激活巨噬细胞和NK细胞,IFN-, IFN-, IFN-, IL-2, TNF- ,细胞因子,产生干扰素,吡喃, 多聚I:C,合成分子,激活巨噬细胞和 NK 细胞 (通过细胞因子),卡介苗, 短小棒状杆菌,胞壁酰二肽,细菌产品,肿瘤免疫治疗进展,肿瘤疫苗研究细胞因子基因修饰的疫苗转染共刺激因子的肿瘤疫苗抗原特异性疫苗细胞因子在肿瘤免疫治疗中的应用增强抗肿瘤潜能的研究DC疫苗在肿瘤免疫治疗中的应用肿瘤抗原修饰的DC疫苗其它细胞因子等修饰的DC疫苗,immunology,肿瘤疫苗的研究,早期试图用死亡的肿瘤细胞或裂解产物来激发特异的免疫反应目前主要集中在基因工程疫苗的研究 细胞因子基因修饰的瘤苗 转染共刺激因子的瘤苗,immunology,抗原特异性疫苗,多肽疫苗几乎都是MHC分子限制性的抗原肽，有成功报道，但有可以导致免疫耐受重组病毒免疫常用痘病毒或腺病毒载体，表达相关的肿瘤抗原重组细菌疫苗多用沙门杆菌、卡介苗等核酸疫苗使用编码肿瘤抗原的裸DNA作疫苗,immunology,DC疫苗的研究,肿瘤抗原修饰的DC疫苗其他因子修饰的DC疫苗：细胞因子、趋化因子等DC疫苗已进入临床实验阶段，初步的研究表明：DC免疫不会引起明显的急性毒性反应；不会产生有明显临床意义的自身免疫性疾病,immunology,细胞因子用于免疫治疗,增强抗肿瘤免疫潜能的研究,重视TNF家族的免疫调节作用热休克蛋白作为抗原载体重视CD4+T细胞的抗肿瘤作用重视DC疫苗的体内效能发挥重视各种方法的联合应用,immunology,重视与其他治疗手段综合、序贯应用,将最新进展转化为临床实践可操作的手段任何免疫治疗都必须与其他治疗手段如手术、放疗、化疗相结合精心优化治疗方案，设计行之有效的肝癌综合治疗策略，降低肝癌转移复发,问题与展望,肿瘤细胞免疫逃避机制未充分了解重视肿瘤微环境对T细胞的抑制作用实验研究向临床实践的转换,immunology,Cancer Despite Immunosurveillance: Immunoselection and Imunosubversion,Shuang-Jian Qiu, MD., PhD.,Zitvogel L, et al. Nature Rev Immunol 2006;6:715-727,Outline,IntroductionCancer immunosurveillanceIntrinsic and extrinstic barriers to carcinogenesisThe six cell-intrinsic hallmarks of cancerThe seventh hallmark of cancerConcluding remarks,Seven hallmarkers of cancer,Cell-intrinsicProvide their own growth signals;Ignore growth-inhibitory signals;Avoid cell death;Replicate without limits;Sustain angiogenesis;Invade tissue;Cell-extrinsicAvoid immunosurveillance.,The immune system can recognize and destroy precursors of cancer before clincally apparent.Initially proposed by Paul Ehlrich a century ago Formally introduced by Burnet and Thomas in the 1950s Criticised by Prehn and others”Immunostimulation theory”considered dead By 1978 Since 1994 key findings rekindle interest in cancer immunosurveillance A broader term, immunoediting, emerged,Immunosurveillance historical perspectives,CD8+ CTLs,recognize and kill stromal and/or tumor cellssecrete the anti-angiogenic cytokine IFN,Defined cancer immunosurveillance (a),convert M1 macrophages into M2 macrophagesrelease IFN, which inhibits angiogenesisproduce IL-4 and block neo-angiogenesis,CD4+ T cells,Defined cancer immunosurveillance (b),Defined cancer immunosurveillance (c),kill tumor cells in TRAIL and perforin-dependent mannera major source of IFNcross-present tumor antigens to T cells,IFN-producing killerdendritic cells (IKDCs),activated by DC in diverse mechanisms,NK cells,Defined cancer immunosurveillance (d),Defined cancer immunosurveillance (e),recognize glycolipids bound to CD1d at the surface of APCsecrete IFN in a CD40- and IL-12-dependent mannerlyse tumor cells though TRAIL or perforin-dependent pathway,NKT cells,Defined cancer immunosurveillance (e),Defined cancer immunosurveillance (f),Tumor cells or APCs activate T cellsproduce cytokineskill tumor cells in an NKG2D-dependent manner, T cells,Defined cancer immunosurveillance (f),Defined cancer immunosurveillance (g),inducing complement-mediated lysis ADC by NK cells and macrophages,Tumor-specific Abs,Defined cancer immunosurveillance (g),Avoidance of immunosurveillance,ImmunoselectionOutgrowth of poorly/non-immunogenic tumor cell variants;Also known as immunoediting;ImmunosubversionSuppress immune responses actively.Cell-extrinsic mechanismsCooperate with the six cell-intrinsic characteristics mechanistically.,Immunoselection,Genomic instability gives rise to genetic diversity in tumors. Natural selection of tumor variants occurs by differential propagation of tumor subclonesThis also applies to tumor growth after effective immunotherapy,three Es of cancer immunoediting,Cancer immunoediting encompasses three process.(a) Elimination corresponds to immunosurveillance.(b) Equilibrium represents the process by which the immune system iteratively selects and/or promotes the generation of tumor cell variants with increasing capacities to survive immune attack. (c) Escape is the process wherein the immunologically sculpted tumor expands in an uncontrolled manner in the immunocompetent host.,Crosstalk of cancer-intrinsic factors and host immune system in multi-step carcinogenesis,Six cell-intrinsic hallmarkers of cancer,Immune system,Intrinsic and extrinsic barriers to carcinogenesis,DNA damageIntrinsic activate the ATMCHK1p53 pathway;lead to cell-cycle arrest or apoptosis.Extrinsic (immune-mediated) Activate the expression of ligands for NKG2D by tumor cells;Render the tumor cells immunogenic and susceptible to killing by NKG2D-expressing NK, NKT, T cells.,Type I IFN and p53Type I IFN have an important role in immunosurveillance;Type I IFN upregulates the p53-mediated response of tumor cells;Loss of p53 increases susceptibility to type-I-IFN-induced, TRAIL-dependent apoptosis.,Intrinsic and extrinsic barriers to carcinogenesis,Self-sufficiency in growth signals,IL-4,IL-6,IL-10IntrinsicAutocrine signals by tumor cells;Extrinsic (immune-mediated)Promote differentiation into TH2 cells;Inhibit crosstalk between innate and adaptive immune response;Stimulate a B7-H4-expressing T-cell suppressing macrophage population.,Impact of Cancer intrinsic Characteristics on IS (a),TGF-IntrinsicTumors disables components of TGF-mediated signal pathway;TGF- favours the epithelial to mesenchymal transition of tumor cells.Extrinsic (immune-mediated)Inhibits antigen presentation;Inhibits T cell proliferation;Inhibits NK cell cytotoxity;Activate regulatory T cell.,Insensitivity to antigrowth signals,Impact of Cancer intrinsic Characteristics on IS (b),BCL-2,MUC1,SurvivinIntrinsicUpregulated anti-apoptotic proteins.Extrinsic (immune-mediated)They are tumor associated or specific antigens; MUC1 inhibits DC differentiation, maturation and induces a regulatory phenotype;Survivin promotes T cell apoptosis through inducing CD95L expressing by tumor cells;,Evasion of apoptosis,Impact of Cancer intrinsic Characteristics on IS (c),APAF1(apoptotic-protease-activating factor 1),IAPs(inhibitor-of-apoptosis proteins)IntrinsicInactivation of APAF1Overexpress IAPsExtrinsic (immune-mediated)Lack of caspase activation affect the immunogenecity of cell deathReduce the immunogenecity of apoptosis,Evasion of apoptosis,Impact of Cancer intrinsic Characteristics on IS (d),Mutated p53,TERT(Telomerase reverse transcriptase)IntrinsicMaintain of the ends of chromosomes;Ensure replicative potential.Extrinsic (immune-mediated)Tumor antigens.,Limitless replicative potential,Impact of Cancer intrinsic Characteristics on IS (d),VEGF,COX2IntrinsicHigher expression by tumor cells;Mediate a proangiogenic swithExtrinsic (immune-mediated)Inhibit T-cell activation and cytotoxity;Promotes TH2-cell responseInhibit NF-kB activation in DCs.,Sustained agiogenesis,Impact of Cancer intrinsic Characteristics on IS (e),MMPs(matrix metalloproteinase)IntrinsicSecreted by tumor cells and stromal cells;Promote tumor-induced angiogenesis, invasion and establishment of metastatic foci.Extrinsic (immune-mediated)Induce cleavage of CD25;Activate TGF-;Promote shedding of ICAM1 and ICAM2.,Tissue invasion and metastasis,Impact of Cancer intrinsic Characteristics on IS (f),NECL2(nectin like 2)a tumor- suppressor gene encoded protein;Mediates epithelial cell junctions through nectin like proteins.IntrinsicInactivated in tumor cells;Allows the disorganization of epithelial-cell layers. productionExtrinsic (immune-mediated)Inhibits NK cell cytotoxity;Inhibits CD8+ T cell IFN production;,Tissue invasion and metastasis,Impact of Cancer intrinsic Characteristics on IS (f),The seventh hallmark of cancer,Tumors evade or paralyse immune system,Tumor variants lose antigen-processing machinery, tumor antigens and sensitivity to immune effectors such as interferons (IFNs),Mech. tumor escape from immune system (a),Tumor-derived factors recruit myeloid suppressor cells (MSCs) and prevent their differentiation into mature DCsMSCs inhibit tumour-specific T cells through arginase-1 (ARG1) or nitric-oxide synthase 2 (NOS2),Mech. tumor escape from immune system (b),Interaction between CD80 or CD86 and CTLA4 induces IFN and immunosuppressive factor IDO by DCsThis results in a reduction in the amount of tryptophan and in the generation of kynurenines, which kill T cells.,Mech. tumor escape from immune system (c),pDCs activated by IL-3 and CD40L promote the differ. into TH2 cells and IL-10-producing CD8+ TregThis state of anergy (with respect to tumour-cell lysis) is mediated by IL-10,directly or indirectly,Mech. tumor escape from immune system (d),Repetitive stimulation of naive T cells with immature DCs results in T-cell anergy, together with IL-10 production and IL-10-independent, cell-contact-dependent regulatory activity,Mech. tumor escape from immune system (e),B7-H1 (and B7-H4) expressed by tumors and it directly promotes T-cell apoptosis through PD1-dependent or