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Immunoregulation. Normal anti-infection anti-tumour. Abnormal Auto-immune disease Tumour Persisitent infection Allergy. Immunoregulation:homostasis. severe inflammation reaction in lung. SARS patient healthy subject. Immunoregulation.
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Normal anti-infection anti-tumour Abnormal Auto-immune disease Tumour Persisitent infection Allergy Immunoregulation:homostasis
severe inflammation reaction in lung SARS patienthealthy subject
Immunoregulation • Regulation of innate immunity • Immunoregulation mediated by Inhibitory Receptor • Regulation by Treg • Idiotype network • Immunoregulation by other mechanism
A. Regulation of innate immunity • Feedback Regulation of secretion of inflammatory factor
PAMP • PAMPs (Pathogen associated molecular patterns) are conserved structures among many pathogens. PAMPs are generated by microbes and not by the host, suggesting that PAMPs are good targets for innate immunity to discriminate between self- and nonself. Furthermore, PAMPs are essential for microbial survival. • LPS, CpG DNA,ssRNA,dsRNA, PGN, LTA, HSP, et al.
PRR • Pattern Recognition Receptors (PRRs) • charateristic • Few diversity • Non clonal ditribution • Immediate immune response
PRR: classification • Mambrane PRR:TLR1,2,4,6;MR;SR; • Secretory PRR:MBL;CRP;LPB; • Cytoplasm RR:TLR3,TLR7/8,TLR9; NLR;RIG-Ⅰ,MDA-5;
SIGIRR ST2 TLR4 CD14 MD2 TIR TIR Rac1 TIRAP PI 3K 受体 衔接蛋白 信号分子 激酶 转录因子 抑制因子 基因转录 激活 抑制 MyD88 PIP2 PIP3 IRAK1 SOCS1 MyD88s IRAK4 IRAK-M TRAF6 MAPK PKB ASK1 NF-B 炎症细胞因子基因转录 固有免疫中针对TLR信号转导的负向调节 TIR: Toll/IL-1 receptor; ASK1: 凋亡信号调节激酶1;IRAK: IL-1受体相关激酶; MAPK: 丝裂原激活 蛋白激酶; MyD88: 髓样分化因子 88; NF-B: 核因子B; PI 3K: 磷酸肌醇 3激酶; PIP2:2磷酸磷脂 酰肌醇; PIP3: 3磷酸磷脂酰肌醇;PKB: 蛋白激酶 B; Rac: 小G蛋白; SIGIRR: 单一Ig IL-1R相关分子; TIRAP: TIR (Toll/IL-1受体) 相关蛋白; TRAF6: TNF 受体相关因子6。
A. Regulation of innate immunity • Regulation by SOCS (suppressor of cytokine signaling)
细胞因子受体 B A 细胞因子 细胞因子受体 细胞 因子 Jak Jak Stat Jak 磷酸 化 Y Yp pY Stat 其它 信号途径 Stat Stat 胞核 胞核 基因转录 DNA 生物学 效应 基因X,Y,Z SOCS 基因 C SOCS1 Jak D SOCS家族部分成员 CIS N端区 SH2结构域 SOCS框 SOCS3 CIS SOCS1 SOCS2 SOCS3 Stat 胞核 蛋白质 泛素化降解 SOCS 蛋白以负向反馈环路阻抑细胞因子的信号转导
Complement regulatory Protein C3 C3 转化酶 C3a C3转化酶 C3转化酶 C3b I factor C3f iC3b I factor+ H Factor C3c 补体成分C3 裂介后产生 的相关分子 C3d C3g C3dg
PTK and PTP 蛋白磷酸化 O ‖ -O-P-O- | O- 蛋白激酶 ATP ADP 蛋白质 蛋白质 + -OH + 蛋白脱磷酸化 O ‖ -O-P-O- | O- O ‖ HO-O-P-O- | O- 蛋白磷酸酶 蛋白质 蛋白质 H2O -OH + + Inhibitory receptor mediated regulation 蛋白磷酸化和脱磷酸化分别由蛋白激酶和蛋白磷酸酶促成
激活性 受体 抑制性 受体 Src PTK ITAM ITIM 磷酸化 PTK Zap-70, Syk SHP-1, SHP-2 PTP 激活 抑制 磷酸化 脱磷酸化 基因转录 免疫细胞激活性受体和抑制性受体及其作用特点
Ag TCR B7 CD28 B7 CTLA-4 ITIM ITAM 24h T细胞 抑制信号 激活信号 CTLA-4对T细胞激活的反馈调节
抗BCR抗体 BCR (mIgM) Ag-Ab复合物 FcRII-B FcRII-B ITIM ITIM 干扰B 细胞激活的信号转导 抑制性受体FcRII-B对抗体产生的反馈性调节
抗BCR抗体(Ab2) BCR (mIgM) FcRII-B ITIM B 细胞激活信号转导受阻 抑制性受体FcRII-B对抗体产生的反馈性调节
Cell Activating receptor Inhibitory receptor T Cell TCR-CD3 CTLA-4, PDL-1, BTLA B cell BCR-Ig/Ig FcRII-B, CD22 NK cell KIR-S + DAP12 CD94/NKG2C + DAP12 NKG2D + DAP10 NCR + /FcR1 CD16 + /FcR1 KIR-L CD94/NKG2A ILT2 Mast cell FcRI FcRII-B CD94/NKG2A T cell V9V2 TCR Activating receptor and Inhibitory receptor of Immune cells
C. Regulation by Treg lymphocytes Naturally Treg and adaptive Treg
Differing immunosuppressive mechanisms used by TReg cells in lymphoid and non-lymphoid tissues. Nature Reviews Immunology 11, 119-130
IL-12 IL-12R IFN-R pMHC TCR CCR5 Stat4 Stat1 CXCR3 IFN IFN- TNF- T-bet IL4 IFNG 细胞免疫 IL-12 Th1 IL-4R pMHC CCR3,4,8 Stat6 IL-4 IL-4 IL-5 IL-13 Gata3 IL-4 IFNG 体液免疫 共刺激 IL4 Th2 初始T Th0 IL-23 IL-23R IL-23 Stat3 IL-17 IL-17 IL-17F RORt IFNG, IL4 炎症反应 IL17 Th17
发挥调节作用的Th1和Th2亚群在功能上的相互拮抗发挥调节作用的Th1和Th2亚群在功能上的相互拮抗 Th1和Th2亚群各自藉助分泌的细胞因子和激活的亚群专一性转录因子以调节性T细胞的形式抑制另一亚群的分化
D. Regulation by idiotypes and anti-idiotypic antibodies Antibodies formed against Ag-binding sites of an Ab are called anti-idiotypic antibodies, and are capable of influencing the outcome of an immune response. Id and AId interactions may enhance or suppress Ab responses.
Isotype The genes for isotype variants are present in all healthy member of a species.
(2) Allotype This refers to genetic variation between individuals within a species.
(3) Idiotype Variation in the V domain ,particularly in CDR, produces idiotype.
Ag epitope Ag Ab1 (Id) Ab2 (AId) Ab3 Ab Idiotype network and antigen internal image
B Ab2 Ab2 Ab1 Ab2 Ab3 / Ab1 A Ab1 Ab2 Ag 削弱Ab1 增强Ab1 利用独特型网络进行免疫干预的两种主要途径
E. Regulation by apoptosis 1. Activation-induced cell death (AICD) Fas (CD95) and FasL • Fas membrane protein is expressed on lymphoid and other cells but is increased in expression with cellular activation. FasL is expressed on activated T cells. Thus, activation of T cells results in the expression of both Fas and FasL. • The intracellular portion of the Fas receptor molecule contains ‘death domains’, which recruit proteins that lead to the activation of a cascade of proteases which induce apoptosis. • Fas-FasL interaction is a major means of mediating AICD in CD4+ T cell.
(1) Fas/FasL and death signal transduction evoked by Fas molecules FasL Fas (receptor) 150 aa Fas (CD95), a type I membrane protein with 325 aa (48 kD) FasL (Fas ligand), a type II membrane protein with 235 aa sFasL DD: death domain 70 aa 80 aa
Fas-FasL pathway Caspase:胱天蛋白酶
Major advances have recently been made in mapping the loci which govern susceptibility to the autoimmune disease. • When the lymphoproliferative (lpr) gene is present in mouse strains, it causes the development of a characteristic clinical syndrome. The mice develop anti-DNA antibodies, rheumatoid factor, circulating IC and glomerulonephritis.
自身抗原驱动下的淋巴细胞克隆扩增 克隆收缩 受阻 AICD 克隆收缩 自身抗原 自身免疫性淋巴 细胞增生综合征 无疾病 A 死亡结构域 Fas lpr Ile Asn FasL gld CYT TM EXT Phe WT TTT GAGGAA TCT AAG ACC TTT TTC GGC TTG TAT AAG gldTTT GAG GAA TCT AAG ACC CTT TTC GGC TTG TAT AAG Leu B
F. Regulation by neuroendocrine system Lymphocytes express receptors for many hormones, neurotransmitters and neuropeptides.
G. Genetic control of immune response Control of immune response by MHC Immune response genes (Ir) control all immune responses Most of the polymorphic residues in MHC molecules reside in the peptide-binding groove MHC restriction APC-Th, Th-B MHC II CTL-Target MHC I
2.Non-MHC-linked genes affect immune response 1)Polymorphisms in the genes encoding cytokine receptors have been shown to correlate with an increased susceptibility to infection, SCID or inflammatory conditions.
2) Genetic control of specificity of an immune response • Antigen is recognized by the lymphocyte that express specific antigen receptor (TCR/BCR) for that antigen. • TCR and BCR are encoded by corresponding genes, thereby specificity of an immune response is genetically controlled.
3) Other non-MHC genes also modulate immume responses • Deficiency in C1q,C1r,C1s SLE and lupus nephritis • Deficiency in C3 bacterial infections • ‘atopy gene’ on human allergy (high IgE chromosome 11q production)
Question • The inhibitory receptors of immune system and its biological significance • Difference between nature Treg and inducible Treg