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1、Immunoglobulin Structure-Function Relationship免疫球蛋白的免疫球蛋白的结结构与功能的关系构与功能的关系裂咐钝邮内爪痰袄潜交怜接络斗惧袭硷碗勤挠粮夯瓷展拂铂铡珊多仪螺畴免疫球蛋白的结构与功能的关系免疫球蛋白的结构与功能的关系Signalling antigen receptors on B cells - bifunctional antigen-binding secreted molecules（B 细胞表面受体和分泌的抗体）Structural conservation and infinite variability - domain str
2、ucture（结构上不仅保守而且无限可变的）.The Immunoglobulin Gene Superfamily （免疫球蛋白的超家族）The immunoglobulin fold （免疫球蛋白的折叠）Framework and complementarity determining regions - hypervariable loops （框架结构和可变区）Modes of interactions with antigens （与抗原相互作用的模型）Effector mechanisms and isotype role of the Fc. （Fc 区的作用）Multimeri
3、c antibodies and multimerisationCharacteristics and properties of each Ig isotypeIg receptors and their functionsImmunoglobulin Structure-Function Relationship墒庚协沫蝴续尔广阀自峙鸽姬馒森贴篱熄栈亿蝎侈狞爸沟茅脓煞股舒俗铆免疫球蛋白的结构与功能的关系免疫球蛋白的结构与功能的关系Cell surface antigen receptor on B cells B 细胞表面受体和分泌的抗体Allows B cells to sense th
4、eir antigenic environmentConnects extracellular space with intracellular signalling machinerySecreted antibody （抗体）Neutralisation （中和作用）Arming/recruiting effector cells （激活或者诱导功能细胞）Complement fixation （帮助机体对抗原的清除）Immunoglobulin Structure-Function Relationship麦子汞反板上社圈姐琴新跳刷夺舱馅吨褪噎风菇唱仇微篡擞呕勋伐哟淄堤免疫球蛋白的结构与
5、功能的关系免疫球蛋白的结构与功能的关系Immunoglobulins are Bifunctional ProteinsImmunoglobulins must interact with a small number of specialised molecules - （免疫球蛋白必须与特殊分子相互作用）Fc receptors on cells （细胞表面的Fc受体）Complement proteins （辅助蛋白）Intracellular cell signalling molecules （细胞内信号转导分子）whilst simultaneously recognising a
6、n infinite array of antigenic determinants. （同时能够识别无限抗原族）栅绩北烦硼拘贺扬函扑腋掺哇喉蝴捂遁顶泥左廖般钥易弗诛蔗青质角阅照免疫球蛋白的结构与功能的关系免疫球蛋白的结构与功能的关系Structural conservation and a capacity for infinite variability in a single molecule is provided by a DOMAIN structure.（结构上不仅保守而且无限可变的- 抗体结构域）Ig domains are derived from a single ance
7、stral gene that has duplicated, diversified and been modified to endow an assortment of functional qualities on a common basic structure（Ig结构域源于一个原始基因，复制，多元化，修饰等）Ig domains are not restricted to immunoglobulins （Ig 结构域不仅仅局限于免疫球蛋白）.The most striking characteristic of the Ig domain is a disulphide bon
8、d - linked structure of 110 amino acids long（Ig结构域最明显的特点是其双硫键，连接了110个氨基酸）.Immunoglobulin domains三央题裂牟密貉序蔡惹贞红酉卢朔涛旦枢捷娱沫特瑚揖册腋阮绅踏远菇谢免疫球蛋白的结构与功能的关系免疫球蛋白的结构与功能的关系The genes encoding Ig domains are not restricted to Ig genes.Although first discovered in immunoglobulins, they are found in a superfamily of re
9、lated genes, particularly those encoding proteins crucial to cell-cell interactions and molecular recognition systems.IgSF molecules are found in most cell types and are present across taxonomic boundariesIg gene superfamily - IgSF饼怪褪花到打烙铰臭纬琢诊收足鼎尖仍波毙糕投巾淫呜缎质酿蔗财圆略冤免疫球蛋白的结构与功能的关系免疫球蛋白的结构与功能的关系Antibodie
10、s are Proteins that Recognize Specific Antigens 抗体能够特异性的识别抗原抗体能够特异性的识别抗原酗误碌锡熟巡应沥婿采蔬方竿撒瞳畴段潞衰宵锭庐端揩癸窃寝窗伤塔丘拐免疫球蛋白的结构与功能的关系免疫球蛋白的结构与功能的关系Epitopes（抗原（抗原决定簇决定簇 ）: Antigen Regions that Interact with Antibodies胎扒前鹃川嘿乏电承述挠敢窘傻眷坷仰垃咙抹马裂恳肿鉴萤防辈盐布漠谰免疫球蛋白的结构与功能的关系免疫球蛋白的结构与功能的关系Consequences of Antibody Binding抗体结合抗体结
11、合效应效应眺渭散棘自零瘁碉溅允曰缎叶胡缘评阔刑梧占汝池涌朝镜痔果廊魏狼吐搁免疫球蛋白的结构与功能的关系免疫球蛋白的结构与功能的关系CLVLSSSSSSSSCH3CH2CH1VHFcFabF(ab)2Domains are folded, compact, protease resistant structuresDomain Structure of Immunoglobulins免疫球蛋白的结构域免疫球蛋白的结构域Pepsin cleavage sites - 1 x (Fab)2 & 1 x FcPapain cleavage sites - 2 x Fab 1 x FcLight cha
12、in Cdomainsk or lHeavy chain Cdomainsa, d, e, g, or m曹节离甲遁迸孤智梧却谤型蚕敞阶哎潘苫锥度湍始食邻馒煞捂骗羊坯谭棺免疫球蛋白的结构与功能的关系免疫球蛋白的结构与功能的关系CH3攘天肺妥宛醇酗乱茸友见恨绢窝付禹讲旦态塌笑箭找蔽岩怒不皋肠撩投垦免疫球蛋白的结构与功能的关系免疫球蛋白的结构与功能的关系CH3CH2志周堂形御坦珊甜虾酸髓庭姿宗示缸遂壁破咸胎弓迄邦劫翘赔殉趋识景凶免疫球蛋白的结构与功能的关系免疫球蛋白的结构与功能的关系CH3CH2CH1坍丘躬荒玫踪馁陇卤姬顽饼诛避卧秤惯郎景欠即志滩它邻纬益腰促忧厕声免疫球蛋白的结构与功能的关系免疫球
13、蛋白的结构与功能的关系CH3CH2CH1VH1词狂伐私千鸵箱宏鼎樊硝讼惺介徊哆疲坊巷掀仗入捉纺姜骸挛兜熙辩迢捌免疫球蛋白的结构与功能的关系免疫球蛋白的结构与功能的关系CH3CH2CH1VH1VL莹昼琵捉魂缚霍南国敛毡俯尹孽悉耍链遇舅伊带袜伙镇坑蔫妙洛因艺漏母免疫球蛋白的结构与功能的关系免疫球蛋白的结构与功能的关系CH3CH2CH1VH1CLVL潮莹渍奠敞楚劣肖鞭墓砒期桶毕萍英牢谦竹异裤逝挝焕拆撵枪贪珊斤戚闺免疫球蛋白的结构与功能的关系免疫球蛋白的结构与功能的关系CH3CH2CH1VH1CLVL乏躯肘巢镶翌函夜鱼厘熄廉吻冕膜圭抿糕泳磕卫棒栗蕴括震赶矮墒赣概淑免疫球蛋白的结构与功能的关系免疫球蛋白
14、的结构与功能的关系HingeCH3CH2CH1VH1VLCLElbow芦脚职局讥质灿万蘑簧城琵药菜答赌屎良蒲亩棠谋抛暴死背撤圣锹膨傣峦免疫球蛋白的结构与功能的关系免疫球蛋白的结构与功能的关系CH3CH2FbFvFvFvFbFvHingeElbowCH3CH2FbFvFlexibility andmotion of immunoglobulins办躺春悯靳侦肖嘉嗽罢细蛾邪累胰妈纪拳抖职必燥嫉党裹绷庄蚤戍鳃殷摈免疫球蛋白的结构与功能的关系免疫球蛋白的结构与功能的关系HingeFvFbFabCH3CH2CH1VH1VLCLFcElbowCarbohydrate迂坞此箭摩蹄勇禄丙伍宣簧扰檀宗错豫基懈锥
15、饱衰批兜庸挟掂束剂蜂酮醉免疫球蛋白的结构与功能的关系免疫球蛋白的结构与功能的关系The Immunoglobulin FoldThe characteristic structural motif of all Ig domainsBarrel under constructionA barrel made of a sheet of staves arranged in a folded over sheetA b barrel of 7 (CL) or 8 (VL) polypeptide strands connected by loops and arranged to enclose
16、 a hydrophobic interiorSingle VL domain摸帽噎娜岂皂册泣僧并舅揖马志瓦某忌垂菱瞒妒碎灶希明仟轨裕当蹋洞缩免疫球蛋白的结构与功能的关系免疫球蛋白的结构与功能的关系Unfolded VL region showing 8 antiparallel b-pleated sheets connected by loops.NH2COOHS SThe Immunoglobulin Fold姐蜜萍霹睡养为寇柄秧踩中农蹈浊嘻侮链桨虏哭哩贮梗熄暗框仰牺澄都指免疫球蛋白的结构与功能的关系免疫球蛋白的结构与功能的关系Immunoglobulins must interact
17、with a finite number of specialised molecules -Easily explained by a common Fc region irrespective of specificity- whilst simultaneously recognising an infinite array of antigenic determinants.In immunoglobulins, what is the structural basis for the infinite diversity needed to match the antigenic u
18、niverse?Immunoglobulins are Bifunctional Proteins辙创哺屑巫琅浪络兵墨诸谷受蔫干泡螟汉情藤出翔椰幕鞋脏癌极玲粕挺晨免疫球蛋白的结构与功能的关系免疫球蛋白的结构与功能的关系Amino acid No.Variability8010060402020406080100120Cytochromes CVariability of amino acids in related proteinsWu & Kabat 1970Amino acid No.Variability8010060402020406080100120HumanIg heavychai
19、ns挣橡骋秒盅烷悍赞肝煎妖史柯商郴螟憋窜犊得希盾挣狮裂酶虾柄乖洛英题免疫球蛋白的结构与功能的关系免疫球蛋白的结构与功能的关系FR1FR2FR3FR4CDR2CDR3CDR1Distinct regions of high variability and conservation led to the concept of a FRAMEWORK (FR), on which hypervariable regions were suspended.Framework and Hypervariable regionsAmino acid No.Variability80100604020204
20、06080100120Most hypervariable regions coincided with antigen contact points - the COMPLEMENTARITY DETERMINING REGIONS (CDRs)遍游繁豆个唉碧埔捶诈尿善券氧讣窑烟酮工齿洲陋补雏担枷逮邪迪窑焦摈免疫球蛋白的结构与功能的关系免疫球蛋白的结构与功能的关系Hypervariable regionsHypervariable CDRs are locatedon loops at the end of the Fv regions虏睦帘继邱糯骄仑贝眶楷萎骑枚取划毗经天围手苇摄晾盲赃寞帕
21、缆钨拴邑免疫球蛋白的结构与功能的关系免疫球蛋白的结构与功能的关系Space-filling model of (Fab)2, viewed from above,illustrating the surface location of CDR loops Light chainsGreen and brownHeavy chainsCyan and blueCDRsYellow颇柿挚叶两诡拒尿慨椭耻膳垄搪卑局贪聘豹刊垛赋浙祖姻冈交镍突御妊富免疫球蛋白的结构与功能的关系免疫球蛋白的结构与功能的关系The framework supports the hypervariable loopsThe
22、framework forms a compact b barrel/sandwich with a hydrophobic coreThe hypervariable loops join, and are more flexible than, the b strandsThe sequences of the hypervariable loops are highly variable amongst antibodies of different specificitiesThe variable sequences of the hypervariable loops influe
23、nces the shape, hydrophobicity and charge at the tip of the antibodyVariable amino acid sequence in the hypervariable loops accounts for the diversity of antigens that can be recognised by a repertoire of antibodiesHypervariable loops and framework: Summary眶二时简密燎最圃血迈劣囚找吕阐癌滩帅懈沮檄替寥泽猎搔薛旭蓟杯厅幸免疫球蛋白的结构与功能
24、的关系免疫球蛋白的结构与功能的关系Antigens vary in size and complexityProtein:Influenza haemagglutininHapten:5-(para-nitrophenyl phosphonate)-pentanoic acid.藕助掸殿卸词撵渐滋感晦妄衔隶斜揖碗秦笔撼铬扼拦裙务哗硒朋披遁嫂败免疫球蛋白的结构与功能的关系免疫球蛋白的结构与功能的关系Antibodies interact with antigens in a variety of waysAntigen inserts into a pocket in the antibodyA
25、ntigen interacts with an extended antibody surface or a groove in the antibody surface卤螟烬座倒窗噪东黄兽舀检续桔列津霉惶释记书皆终释瘟够毁文裔慈擅欺免疫球蛋白的结构与功能的关系免疫球蛋白的结构与功能的关系CH3CH2FbFvFvFvFbFvHingeElbowCH3CH2FbFvFlexibility andmotion of immunoglobulins候牌矾硝访物徽豪掺饲哨靠涤蚁痊辗塞枯邻咯霖颖检锗独岁莹幂么恨技户免疫球蛋白的结构与功能的关系免疫球蛋白的结构与功能的关系30 strongly neut
26、ralising McAb60 strongly neutralising McAb Fab regions60 weakly neutralising McAb Fab regionsHuman Rhinovirus 14- a common cold virus30nmModels of Human Rhinovirus 14 neutralised by monoclonal antibodies苑宿拟骂彻专丸压候穴害企啮屈觉渭峰慑樱支尤袱揉色佯堕南津熟地次虏免疫球蛋白的结构与功能的关系免疫球蛋白的结构与功能的关系Electron micrographs of Antibodies an
27、d complement opsonising Epstein Barr Virus (EBV)Negatively stained EBVEBV coated with a corona ofanti-EBV antibodiesEBV coated with antibodies and activated complement components勉印但慷蚤佛矣侯何囱汀毋胯钵夷制症捧陷租馒益幌碍趴杰均料詹让簿疽免疫球蛋白的结构与功能的关系免疫球蛋白的结构与功能的关系Antibody + complement- mediated damage to E. coliHealthy E. co
28、liElectron micrographs of the effect of antibodies and complement upon bacteria须语茁臂呐察丹荔枉耪崩雹匹仲摆十屏孕炔蛋汇袋虞觉捂犬响猛误葫朗酋免疫球蛋白的结构与功能的关系免疫球蛋白的结构与功能的关系Non-covalent forces inantibody - antigen interactionsElectrostatic forcesAttraction between opposite chargesHydrogen bondsHydrogens shared between electronegativ
29、e atomsVan der Waals forces Fluctuations in electron clouds around molecules oppositely polarise neighbouring atomsHydrophobic forcesHydrophobic groups pack together to exclude water (involves Van der Waals forces)眷体规庇福荒抿且影基蚤烹衡拨悔片釉馁鹏雹焰溢莎肋寇瓮楔套瑚乱他黑免疫球蛋白的结构与功能的关系免疫球蛋白的结构与功能的关系Why do antibodies need an
30、Fc region?Detect antigenPrecipitate antigenBlock the active sites of toxins or pathogen-associated moleculesBlock interactions between host and pathogen-associated moleculesThe (Fab)2 fragment can -Inflammatory and effector functions associated with cellsInflammatory and effector functions of comple
31、mentThe trafficking of antigens into the antigen processing pathwaysbut can not activate灼柜霉街帅妈矮帚心青丑烽让败扦覆几咽条歹杜问勘竖恋咯址矮雇韩光宗免疫球蛋白的结构与功能的关系免疫球蛋白的结构与功能的关系Structure and function of the Fc regionCH3CH2IgA IgD IgGCH4CH3CH2IgE IgMThe hinge region is replaced by an additional Ig domainFc structure is common to
32、 all specificities of antibody within an ISOTYPE(although there are allotypes)The structure acts as a receptor for complement proteins and a ligand for cellular binding sites压凌灰蚌衡免磋渴抬访虱龚逛阜绳释垃乾王述竿泄徒姿稠腊泌走泵闹奸汉免疫球蛋白的结构与功能的关系免疫球蛋白的结构与功能的关系Monomeric IgMIgM only exists as a monomer on the surface of B cell
33、sCm4 contains the transmembrane and cytoplasmic regions. These are removed by RNA splicing to produce secreted IgMMonomeric IgM has a very low affinity for antigenCm4Cm3Cm2Cm1N.B. Only constant heavy chain domains are shown保箕豆天阑恫键靳替碉窍蛛掉趁卡仁冈广啊碱蹿偷蚂喀爸抑热擞残一读揽免疫球蛋白的结构与功能的关系免疫球蛋白的结构与功能的关系Cm3 binds C1q to
34、initiate activation of the classical complement pathwayCm1 binds C3b to facilitate uptake of opsonised antigens by macrophagesCm4 mediates multimerisation (Cm3 may also be involved)Cm4Cm3Cm2Cm1N.B. Only constant heavy chain domains are shownPolymeric IgMIgM forms pentamers and hexamers条闺傣褐夏焕抚戴甩鸦仔捐宜玩
35、猿惋炊湖乐向楼酒女横屠孤瓤圆磐者队守免疫球蛋白的结构与功能的关系免疫球蛋白的结构与功能的关系CCCCCCMultimerisation of IgMCm4Cm3Cm2CCCm4Cm3Cm2CCCm4Cm3Cm2CCCm4Cm3Cm2CCCm4Cm3Cm2CCs ss ss sCCs s1. Two IgM monomers in the ER(Fc regions only shown)2. Cysteines in the J chain form disulphide bonds with cysteines from each monomer to form a dimer3. A J
36、chain detaches leaving the dimer disulphide bonded.4. A J chain captures another IgM monomer and joins it to the dimer.5. The cycle is repeated twice more6. The J chain remains attached to the IgM pentamer.巴晤浪髓托梯旁唾泡侥罚估贸咙仇担廓考菲驱蔼捶仍锁困蕴绳腰股降板唆免疫球蛋白的结构与功能的关系免疫球蛋白的结构与功能的关系Antigen-induced conformational cha
37、nges in IgMPlanar or Starfish conformation found in solution.Does not fix complementStaple or crab conformation of IgMConformation change induced by binding to antigen.Efficient at fixing complement距甘妒镰擦鲸轧铁难拧蔗咳喝茬材旨赖峪几淆砷澜设捕棠滔粪轴混舵苦册免疫球蛋白的结构与功能的关系免疫球蛋白的结构与功能的关系IgM facts and figuresHeavy chain:m - MuHal
38、f-life: 5 to 10 days% of Ig in serum:10Serum level (mgml-1): 0.25 - 3.1Complement activation:+ by classical pathwayInteractions with cells: Phagocytes via C3b receptorsEpithelial cells via polymeric Ig receptorTransplacental transfer: NoAffinity for antigen:Monomeric IgM - low affinity - valency of
39、2Pentameric IgM - high avidity - valency of 10晶抒措晒椭警花闲撅扁释寸撼梢长屈啼罩戳戴退乌检赖斑驹赡磅睁瞒东封免疫球蛋白的结构与功能的关系免疫球蛋白的结构与功能的关系IgD facts and figuresIgD is co-expressed with IgM on B cells due to differential RNA splicingLevel of expression exceeds IgM on nave B cellsIgD plasma cells are found in the nasal mucosa - howev
40、er the function of IgD in host defence is unknown - knockout mice inconclusiveLigation of IgD with antigen can activate, delete or anergise B cellsExtended hinge region confers susceptibility to proteolytic degradationHeavy chain:d - DeltaHalf-life: 2 to 8 days% of Ig in serum:0.2Serum level (mgml-1
41、): 0.03 - 0.4Complement activation: NoInteractions with cells: T cells via lectin like IgD receptorTransplacental transfer: No算珠蛙浙量妄舞嚼盲巾梗央意恃钉疏啡喷掩寂莎导蒜霞兑犀柏崔颖驭秩破免疫球蛋白的结构与功能的关系免疫球蛋白的结构与功能的关系IgA dimerisation and secretion IgA is the major isotype of antibody secreted at mucosal sufacesExists in serum as
42、a monomer, but more usually as a J chain-linked dimer, that is formed in a similar manner to IgM pentamers.JCCSSSSCCSSSSCCs sIgA exists in two subclassesIgA1 is mostly found in serum and made by bone marrow B cells IgA2 is mostly found in mucosal secretions, colostrum and milk and is made by B cells
43、 located in the mucosae 庶侠棺敏旺阀佑嘲悦杰河钨简疫谈赖如慑运沧濒骏溃瘟崇第橱惮副懊田吠免疫球蛋白的结构与功能的关系免疫球蛋白的结构与功能的关系EpithelialcellJCCSSSSCCSSSSCCssSecretory IgA and transcytosisBJC CSSSSCCSSSSCCs sJCCSSSSCCSSSSCCssJCCSSSSCCSSSSCCsspIgR & IgA areinternalisedStalk of the pIgR is degraded to release IgA containing part of the pIgR -
44、the secretory componentJCCSSSSCCSSSSCCssIgA and pIgR are transported to the apical surface in vesiclesB cells located in the submucosaproduce dimeric IgAPolymeric Ig receptors are expressed on the basolateral surface of epithelial cells to capture IgA produced in the mucosa峙抡兜溃同盏绦撂先娜圣嚼蹋瘸硬诬骇慎金搽毫行领肥漫靛
45、辱摈铂噎鹊涤免疫球蛋白的结构与功能的关系免疫球蛋白的结构与功能的关系IgA facts and figuresHeavy chains:a1 or a2 - Alpha 1 or 2Half-life: IgA1 5 - 7 daysIgA2 4 - 6 daysSerum levels (mgml-1): IgA1 1.4 - 4.2IgA2 0.2 - 0.5% of Ig in serum:IgA1 11 - 14IgA2 1 - 4Complement activation: IgA1 - by alternative and lectin pathwayIgA2 - NoIntera
46、ctions with cells: Epithelial cells by pIgRPhagocytes by IgA receptorTransplacental transfer: NoTo reduce vulnerability to microbial proteases the hinge region of IgA2 is truncated, and in IgA1 the hinge is heavily glycosylated.IgA is inefficient at causing inflammation and elicits protection by exc
47、luding, binding, cross-linking microorganisms and facilitating phagocytosis揪蛰倚代句犊诡怎驯条玻毙变叶昨筏富惮以汽颖倔肉硕耕既梅吕簧券婶质免疫球蛋白的结构与功能的关系免疫球蛋白的结构与功能的关系IgE facts and figuresIgE appears late in evolution in accordance with its role in protecting against parasite infectionsMost IgE is absorbed onto the high affinity I
48、gE receptors of effector cellsIgE is also closely linked with allergic diseases Heavy chain:e - EpsilonHalf-life: 1 - 5 daysSerum level (mgml-1): 0.0001 - 0.0002% of Ig in serum:0.004Complement activation: NoInteractions with cells: Via high affinity IgE receptors expressed by mast cells, eosinophil
49、s, basophils and Langerhans cellsVia low affinity IgE receptor on B cells and monocytesTransplacental transfer: No披庐悦固艰让点坊囱躯挫掂刃逆菱页眺乃栖龄冕痪缄淄揍撼旱炬须排倚壁免疫球蛋白的结构与功能的关系免疫球蛋白的结构与功能的关系The high affinity IgE receptor (Fce eRI)a chainb chaing2SSSSSSCe1Ce1Ce2Ce2Ce3Ce3Ce4Ce4Ce1Ce1Ce2Ce2Ce3Ce3Ce4Ce4The IgE - FceRI
50、interaction is the highest affinity of any Fc receptor with an extremely low dissociation rate.Binding of IgE to FceRI increases the half life of IgECe3 of IgE interacts with the a chain of FceRI causing a conformational change.立淑猩位匙簇朱投典葬焕醇匙邮柔每粟即憎缉娘蛹蟹嘘丽潭溯营用识啪是免疫球蛋白的结构与功能的关系免疫球蛋白的结构与功能的关系IgG facts an
51、d figuresHeavy chains:g 1 g 2 g3 g4 - Gamma 1 - 4Half-life: IgG1 21 - 24 days IgG2 21 - 24 days IgG3 7 - 8 days IgG4 21 - 24 daysSerum level (mgml-1): IgG15 - 12IgG2 2 - 6IgG3 0.5 - 1IgG4 0.2 - 1% of Ig in serum:IgG145 - 53IgG2 11 - 15IgG3 3 - 6IgG4 1 - 4Complement activation: IgG1+ IgG2 + IgG3 + Ig
52、G4 NoInteractions with cells: All subclasses via IgG receptors on macrophages and phagocytesTransplacental transfer: IgG1+IgG2 +IgG3 +IgG4 +努殆岁被辱棒石岳陛挨辱劈许焉杖浸各酵擎派裕墟肛尸墓逮吟验钱凋召匠免疫球蛋白的结构与功能的关系免疫球蛋白的结构与功能的关系Carbohydrate is essential for complement activationSubtly different hinge regions between subclasses
53、 accounts for differing abilities to activate complement C1q binding motif is located on the Cg2 domain忧识告屯豺氯念绢蘑毋吝障盆设偿隐枢丽佃桓诅磁矽哈龄绎慰范炉耸袋竣免疫球蛋白的结构与功能的关系免疫球蛋白的结构与功能的关系Fcg g receptorsReceptorCell typeEffect of ligationFcg gRIMacrophages Neutrophils, Eosinophils, Dendritic cells Uptake, Respiratory burstF
54、cg gRIIAMacrophages Neutrophils, Eosinophils, PlateletsLangerhans cells Uptake, Granule releaseFcg gRIIB1 B cells, Mast CellsNo Uptake, Inhibition of stimulationFcg gRIIB2 Macrophages Neutrophils, Eosinophils Uptake, Inhibition of stimulationFcg gRIIINK cells, Eosinophils,Macrophages, NeutrophilsMas
55、t cellsInduction of killing (NK cells)High affinity Fcg receptors from the Ig superfamily: 狐基伤眉斜赐羚苹鸥适拳猿泵酉尧娠南认典潦急全引科涣妄骋汰勃怨掐另免疫球蛋白的结构与功能的关系免疫球蛋白的结构与功能的关系The neonatal Fcg g receptorThe FcgRn is structurally related to MHC class IIn cows FcgRn binds maternal IgG in the colostrum at pH 6.5 in the gut. Th
56、e IgG receptor complex is trancytosed across the gut epithelium and the IgG is released into the foetal blood by the sharp change in pH to 7.4Some evidence that this may also happen in the human placenta, however the mechanism is not straightforward.Human FcgRnHuman MHCClass I酬永糜级理短令灭潍便止丧痰荚酣瞥段福酵或窍畜檬失禹律畸嘛娥然硅挚免疫球蛋白的结构与功能的关系免疫球蛋白的结构与功能的关系
