免疫球蛋白.ppt

3.Hydrolytic fragment of Ig
(pepsin)
(papain)
1 F(ab’)2 +pFc’
2 Fab + 1Fc
4. Joining chain
＆ secretory piece
A.Joining chain
n(H2L2) J chain (H2L2)n J
n(monomer)
agglutinate bacteria 中和作用
激活补体
通过胎盘
2. C region
activate complement binding to FcR on surface of cells transfer across placenta (IgG)
与Ag特异性结合 结合Fc受体
被动免疫
ADCC
3. IgA : monomer or dimer (secretory IgA,SIgA)
---分泌型IgA粘膜局部抗感染重要;婴儿从初乳可获得SIgA
4. IgD : monomer (H2L2)
---mIgD是BCR和B细胞成熟标志
5.IgE : monomer (H2L2)
---血中含量最少;介导Ⅰ型超敏反应
L chain
κ/λ (2:1)
H2L2 2 region hinge
H chain
(,,,,)
V region
(Ag-biding site)
C region
Monomer of Ig
Ag-biding site
---made up of
VH and VL (HVR/CDR)
HVR1/CDR1 HVR2/CDR2
polymer
B.Secretory piece (SP) or
(H2L2)2 J dimer
(H2L2)5 J pentamer
secretory component (SC)
---保护SIgA并介导IgA分泌到粘膜表面
C.Secretory IgA: (H2L2)2-SC-J
五类免疫球蛋白结构的异同
(antibody)
Physicochemical
properties of Ab
球蛋白
•gamma-globulin
•heterogenicity (异质性)
正常人血清电泳分离图
2. Immunoglobulin (Ig)
A. Conception
具有抗体活性或化学结构与抗体 相似的球蛋白统称为免疫球蛋白(Ig)
Ⅳ.Characteristics and Functions of 5 Ig Classes
1.IgG: H2L2, IgG1 to IgG4
---含量最多,免疫防御最重要;新生儿抗感染重要;用于紧急预防
2. IgM: (H2L2)5J, pentamer
---分子量最大, 血管内抗感染的主要抗体;最早合成和分泌 (早期诊断和宫内感染指标); mIgM是BCR(单体)
Ⅰ. Introduction
1.Antibody (Ab)
neutralize
exotoxin bacteria
animal
antitoxin specific (in serum) substanceagglutinin
Ag
agglutinate
Ab
含有抗体的血清
称为免疫血清
Discovery of antibody
Chapter 3
Outline
➢Introduction (conception of Ab and Ig) ➢Structure of Immunoglobulin ➢Function of Immunoglobulin ➢Characteristics and Functions
of 5 Ig Classes ➢Monoclonal Antibody
CH4
J chain
SC
CH4 J chain
Ⅲ.Functions of Ig
1. V region (recognize and combine with Ag specifically)
neutralize exotoxin and virus
阻止病原体入侵 溶解细胞/细菌 调理作用
inhibit adhesion
FR1 FR2
HVR (hyper-
HVR3/CDR3
FR3 FR4
variable region)
CDR(complementarity determining region)
FR (framework region)
2. Domain of Ig
IgG
VH/VL --- Ag-binding site (HVR/CDR)
调理作用 介导Ⅰ型超敏反应
Antibody-dependent cell -mediated cytotoxicity(ADCC)
(抗体依赖的细胞介导的细胞毒作用)
IgG
Ag
Ag
(Ab包被的靶细胞)
ADCC--- 指IgG类抗体与靶细胞表面抗原特异性结合后， 表达IgG FcR的效应细胞(NK细胞、巨噬细胞和中性粒细胞) 可通过与靶细胞表面IgG的Fc段结合，而直接杀伤被抗体包被 的靶细胞
Ⅴ.Monoclonal Antibody
CH1/CL ---genetic marker of allotype
CH3,4--- binding to FcR on surface of cells(CH2, 3 of IgE binding to FcR)
19
CH2--- complement C1q binding site
(CH3 of IgM)
Conception of
AbAg → B cell • can combine with corresponding Ag
↓
• immune functions
百度文库
plasma cell ↓
抗体是B细胞受抗原刺激后,增 殖分化为浆细胞所产生的一种能与 相应抗原结合、具有免疫功能的球
globulin 蛋白
B. Expression of Ig
Secreted Ig (SIg) Membrane Ig (mIg )
Ⅱ. Structure of Ig
1.Basic structure of Ig
* tetrapeptide chain structure * monomer of Ig (appear Y shaped) ---basic unit of Ig molecule