医学免疫学-抗原课件

Antigen,抗原,chapter 2, Conceptions Immunogenicity and Specificity of Antigen Classification of Antigen Superantigen and Adjuvant,.Conception,Antigen (抗原) Complete antigen (完全抗原) Hapten (半抗原) Tolerogen (耐受原) Allergen (变应原),1.Antigen (Ag), BCR,TCR,A.Definition of Ag,-抗原是能与B 、 T 淋巴细胞抗原识别受体结合,启动免疫应答,并能与应答产物 ( 抗体或效应T细胞) 发生特异性结合的物质,B.2 important properties of Ag, immunogenicity antigenicity,B,T,combine specifically,pathogenB cell corresponding antibody,Ag,(Ab),B.2 important properties of Ag, Immunogenicity,antigen IS induce IR products of IR (Ab/effector T cells),Combine specifically,immunogenicity,免疫原性是指能够刺激机体产生特异性免疫应答，包括诱导产生抗体及效应性T 淋巴细胞的能力,Antigenicity/immunoreactivity,-the ability for inducing an IR, including induce production of antibody and effector T cell,-the ability to combine specifically with the Ab or effector T cell induced by its own,-能与其诱生的抗体或效应性T细胞发生特异性结合的能力,称为抗原性或免疫 反应性,antigenicity,2.Complete antigen & hapten,A.Complete antigen (完全抗原),-Substances that have both immuno-genicity and immunoreactivity(antigenicity),B.Hapten (半抗原),-Substances that have immunoreactivity , but lack of immunogenicity, hapten+carrier = complete antigen,半抗原,(无免疫原性), Hapten couple(偶联) to protein or other carriers (载体) to form complete antigen,(有免疫原性),(二硝基苯),combine with,(有免疫反应性),combine with,combine with,anti-dinitrobezene (抗二硝基苯),3.Tolerogen & allergen,antigen T/B response, Tolerogen,antigen T/B high response, Allergen,“hypersensitivity/allergy” (超敏反应/变态反应),negative,“immune tolerance” (免疫耐受),(state of specific nonresponse),.Immunogenicity and Specificity of antigen,1.Decisive factors for immunogenicity,A.Foreigness(异物性), Non-self substances Self tissue,B.Physicochemical characteristics,在胚胎期未与免疫活性细胞充分接触过的物质均为异物, various microbes allogenic substance heterogenic protein (such as immune sera),(including: changed or cryptical),Glutin (明胶),Glutin,+2% tyrosine (酪氨酸),免疫原性弱,免疫原性增强,B.Physicochemical characteristics,MW100kD,Chemical property Molecule weight,Complexity of structure Molecular conformation and accessibility,（分子构象和易接近性）,Y,Y,Glutan,Immunogenicity +,±,+,分子构象和易接近性不同,其免疫原性也不同,Tyrosine,poly-lysine,poly-alanine,Physical property,C.Host D.Immunized route, Genetic characteristics of the host Age, sex, and state of health,多价抗原,多价抗原,specificity of immunogenicity,A.Antigenic determinant (AD),specificity of immunoreactivity,induce,binding to,AD,AD,2. Specificity of antigen,抗原分子中决定抗原特异性的特殊化学基团称为抗原决定基,又称为表位(epitope); 是与TCR/ BCR及抗体特异性结合的基本单位, Antigenic valence,能与抗体结合的抗原决定基(表位)的数目,称为抗原的结合价,A. Antigenic determinant (AD),Ag,antigen,antigen, Definition,抗原分子中决定抗原特异性的特殊化学基团称为抗原决定基,又称为表位(epitope); 是与TCR/BCR及抗体特异性结 合的基本单位,Ag,Ag,B,T,AD,抗间位氨基苯磺酸抗体,(半抗原),The chemical composition and spatial structure of AD decide specificity of Ag,苯磺酸基,苯砷酸基,甲酸基,-The numbers of epitope which can bind to antibody, Antigenic valence,*Natural antigen is polyvalent antigen,抗原,AD,能与抗体结合的抗原决定基(表位)的数目,称为抗原的结合价,多价,B. Classification of AD, According to structure of AD, functional determinant cryptical determinant, According to location of AD on Ag molecule, linear determinant conformational determinant, According to AD recognized by T or B cell, T cell epitope B cell epitope, Hapten epitope and carrier epitope,(i.e. B cell epitope and T cell epitope),T cell epitope-epitope recognized by TCR, B cell epitope-epitope recognized by BCR/Ab,T细胞只识别经加工处理的线性表位，一般不识别构象决定基,*linear determinant *location in the inside of antigen,*conformational determinant or linear determinant *location on the surface of natural antigen,B细胞可识别线性表位或构象决定基，且无需加工处理,3,2,1,2: B细胞表位 3 :T 细胞表位,3,1,交叉反应,Ag1,Ag2,C.Common antigen and cross-reaction,两种不同抗原具有相同或相似的抗原决定簇,则称为共同抗原(common antigen),抗体对具有相同或相似的抗原决定簇的不同抗原的反应,称为交叉反应(共同抗原又称交叉反应抗原), Cross-reaction, Common antigen,. Classification of antigen,1.Depend on whether need the Th cell for producing the antibody,A.Thymus dependent antigen(TD-Ag),B.Thymus independent antigen(TI-Ag),2. Depend on the consanguinity between the Ag and organism,Xenogenic Ag （异种抗原） B. Allogenic Ag （同种异型抗原） C.Autoantigen（自身抗原） D.Heterophilic antigen (异嗜性抗原) or Forssam antigen E.Idiotype Ag,(亲缘关系),.Superantigen and adjuvant,1. Superantigen,一种在极低浓度下(110ng/ml)即可激活大量T细胞克隆,并产生极强的免疫应答的特殊抗原类物质,称为超抗原,A.Conception B. Types,exogenous superantigen 如金葡菌肠毒素AE endogenous superantigen 如逆转录病毒的蛋白产物,C. Characteristic and mechanism,TCR+T cell superantigen 如热休克蛋白(HSP) B cell superantigen 如金葡菌蛋白A(SPA),the other terminal of SAg combine with TCRV of CD4+T cell,a terminal of SAg directly binding to nonpolymorphic region of MHC-,*The difference between common Ag and Sag (Conbinate site, not processed by APC, no restriction