W2+-天然免疫

1、Innate Immunity秦志海秦志海, M.D.Lab phone: 64888435E-mail: INNATERESPONSEPRRsPAMPsCytokinesAntigenPresentationCo-ReceptorsGenetic FactorsADAPTIVE RESPONSEGenetic FactorsCELLULARIMMUNITYHUMORALIMMUNITYResolutionMemoryHow do organisms defend themselves against disease? PAMPs: Pathogen-associated molecular

2、patternsPRRs: Pattern-Recognition ReceptorsProgression of ImmunityInnate Immunity General features of Innate Immunity Major cell players Macrophage Neutrophil Natural Killer (NK) cells Mast cell Pattern-Recognition Receptors (PRRs) ComplementRussian embryologist and immunologist; founder of comparat

3、ive immunology whose influential phagocytosis theory was the starting point of Innate Immunology. lie Metchnikoff (1845-1916) Immunologist at Yale University whose research has had a profound effect on the understanding of the immune system, who studied innate immunity (the bodys first natural defen

4、ses against infection) and how T-cells react with pathogens, and who wrote the textbook “Immunobiology: The Immune System in Health and Disease”, Charles A Janeway(1943-2003) Components of Innate Immunity Components Principle FunctionsBarriersEpithelial layers Prevent entryDefensins and Cryptdins Mi

5、crobial killingCirculating and Tissue Effector CellsMacrophages Efficient phagocytosis and killing of microbes: cytokinesNeutrophils Early phagocytosis and killing of microbesMast Cells Release of inflammatory granulesEosinophils Nasty toxic cells designed to kill helminths (worms)Natural killer cel

6、ls Lysis of infected cells, activation of macrophagesCirculating ProteinsComplement (C) Killing of microbes, opsonization of microbes, activation leukocytesMannose binding protein Opsonization of microbes and activation of CC-reactive protein Opsonization of microbes and activation of CLysozyme Bact

7、erial cell wall lysisCytokinesTNF, IL-1, 6, 18 InflammationIFN, Resistance to viral infectionIFN Macrophage activationIL-12 IFN production by NK cellsIL-15 Proliferation of NK cells, memory T cellsIL-10, TGF Control of InflammationNeutrophilsMacrophagesB CellsT CellsHumoral ImmunityCell-Mediated Imm

8、unityInnate ImmunityAdaptive ImmunityMicrobial Pattern Molecules Specific Antigens + Co-stimulationRapid Response Delayed ResponseNo Memory MemoryInnate vs Adaptive ImmunityCD4+CD8+Dendritic cellsNature Killer cells 天然免疫與特異性免疫的識別特點天然免疫與特異性免疫的識別特點 識別特點識別特點 天然免疫天然免疫 特異性免疫特異性免疫 識別抗原種類識別抗原種類 僅識別微生物僅識別微生

9、物 既可識別微生物分子抗原既可識別微生物分子抗原 和靶分子結(jié)構(gòu)和靶分子結(jié)構(gòu) 及其產(chǎn)物的組分（及其產(chǎn)物的組分（PAMPPAMP） 也可識別非微生物抗原也可識別非微生物抗原識別的特異性識別的特異性 泛特異性泛特異性 高度特異性高度特異性 識別不同種類的微生物識別不同種類的微生物 微生物的不同抗原表位微生物的不同抗原表位 識別受體基因識別受體基因 在胚系中編碼在胚系中編碼 在個體發(fā)育過程中重排在個體發(fā)育過程中重排 （BCRBCR體細胞基因突變）體細胞基因突變） 識別受體分布識別受體分布 非克隆化非克隆化 克隆化克隆化 The front line of host defenseExample: Co

10、mplement (C)Example: Interferon“Great Wall” of Host DefensePhagocytes are the Most Important CellsPhagocytes: MacrophagePhagocytosis, Intracellular and extracellular killing, Tissue repair, Antigen presentation for specific immune response,Secreting cytokines. The macrophage is the large, yellowish

11、cell with projections; the bacterial cells are small, rod-like, blue cells. Macrophages are important first responders to infection and tissue damageAlveolar macrophages (lung) Histiocytes (connective tissue) Kupffer cells (liver) Mesangial cells (kidney) Microglial cells (brain)Tissue macrophage Di

12、fferent namesMacrophages phagocytose and degrade foreign particles,bacteria and dead (and dying) host cells.Receptors on Macrophages:LPS receptor-CD14Toll-like receptorsFc receptorsMannose receptorComplement receptorsIFNg receptorChemokine receptorsRecruitment and activation of phagocytesInflammatio

13、nFigure 2-9RecruitmentPhagocytosisMicrobicidal mechanisms of phagocytesCytokine productionMacrophages: friends or foes?Current Opinion in Immunology 2010, 22:231237Orchestration of TAM in cancer promoting inflammationMacrophages, innate immunity and cancerCurrent Opinion in Immunology 2010, 22:23123

14、7MDSCMDSC在體內(nèi)的積聚需要在體內(nèi)的積聚需要TNFTNF受體的激活受體的激活Zhao X, Qin ZH et al., 2012, J Clin InvestPhagocytes: NeutrophilsFunction:phagocytosis, intracellular killing, inflammation/tissue damage Characteristic: nucleus, cytoplasm,granules,CD66 markerExpress some of the same receptors found on macrophages. These cel

15、ls are specialized in killing and swallowing microbes.LPS receptor:CD14toll-like receptor-4CR3,4:Complement (C) receptors (C3b)Scavenger receptor:sialic acid-bearing proteinMannose receptor:Binds mannose on bacteria, activates CGlycan receptor:PolysaccharidesIN ADDITION: TLRsPhagolysosome formation

16、Neutrophil 30 minutes after ingestion of C. albicans. The cytoplasm is already partly degranulated and two lysosomal granules (arrowed) are fusing with the phagocytic vacuole.Mast cells induce an inflammatory cascadeMast cells can also secrete:u Cytokines to induce inflammationu Chemokines to induce

17、 infiltration by monocytes, and neutrophilsu Leukotrienes to induce muscle contraction and increase vascular permeabilityNK cells are large granular lymphocytes (LGL)Kill infected and malignant cellsIdentified by the presence of CD56 & CD16Absence of CD3Activated by IL2 and IFN- to become LAK ce

18、llsRegulation of NK Cell FunctionThe mononuclear phagocyte systemTranscriptional regulation of macrophage polarization: enabling diversity with identity. - Focus on: Monocytes and macrophages. Nature Rev. Immunol. 2011Myoloid colony-forming unitsPattern recognition in the innate immune systemPathoge

19、n associated molecular pattern, PAMP 一類或一群特定的微生物病原體（及其產(chǎn)物）共有的某些非特異性、高度保守的分子結(jié)構(gòu)，其可被特異性免疫細胞所識別。病原微生物所特有微生物生存和致病性所必需宿主泛特異性識別的分子基礎(chǔ)Pattern-Recognition receptor，PRR 是一類表達于天然免疫細胞表面、非克隆性分布、可識別一種或多種PAMP的識別分子。調(diào)理作用吞噬作用啟動細胞活化和炎癥信號轉(zhuǎn)導(dǎo)誘導(dǎo)凋亡循環(huán)在體液中的體液成分循環(huán)在體液中的體液成分：急性期反應(yīng)蛋白或補體細胞表面表達的胞吞受體細胞表面表達的胞吞受體：清道夫受體、凝集素受體調(diào)理吞噬細胞的受體調(diào)理

20、吞噬細胞的受體：Fc、補體受體信號轉(zhuǎn)導(dǎo)受體信號轉(zhuǎn)導(dǎo)受體：TLR、NLR、RLRPRR分類分類Mannose-binding lectin （MBL）Mannose-binding lectin recognizes bacterial surfaces by their particular spacing of carbohydrate.甘露糖結(jié)合凝集素PRRToll mutant lacks defense against fungal infections18 Wheeler lacks defense against bacteriaThis led to the discovery

21、of a family of receptors known as the Toll-related receptors (TLR) present in vertebratesEstablishment of dorsal-ventral polarity in the Drosophila embryo: genetic studies on the role of the Toll gene product.Anderson KV, Jrgens G, Nsslein-Volhard C.Cell. 1985 Oct;42(3):779-89.Christiane Nsslein-Vol

22、hard (born October 20, 1942 in Magdeburg) is a German biologist who won the Albert Lasker Award for Basic Medical Research in 1991 and the Nobel Prize in Physiology or Medicine in 1995, together with Eric Wieschaus and Edward B. Lewis, for their research on the genetic control of embryonic developme

23、nt.Immunity in Drosophila (Innate)1980，Nusslein-Volhard， Nature在研究果蠅胚胎發(fā)育過程中發(fā)現(xiàn)有一個基因決定著果蠅的背腹側(cè)分化，將其命名為Toll基因。1988年，年，Hashimoto， Cell，Toll基因編碼一種跨膜蛋白質(zhì)，并闡明了Toll蛋白的結(jié)構(gòu)。1991，Gay，NatureToll蛋白在結(jié)構(gòu)上與哺乳動物中一種天然免疫功能分子白細胞介素受體1 （IL-1）具有同源性：二者的細胞質(zhì)部分相似。1994，Nomura，DNA Res首先報道了人中的Toll樣受體。1996，Jules A. Hoffmann，Cell發(fā)現(xiàn)Tol

24、l在果蠅對真菌感染的免疫中起著重要作用，從而確立了Toll的免疫學(xué)意義。1997年，年，Charles Janeway和和Ruslan Medzhitov， Nature闡明了一種Toll樣受體（后來被命名為TLR4）能夠激活與適應(yīng)性免疫有關(guān)的基因。1998，Bruce A. Beutle，ScienceTLR4能夠探測LPS的存在。小鼠中的TLR4突變而喪失功能，小鼠不會對LPS起反應(yīng)。TLR的發(fā)現(xiàn)的發(fā)現(xiàn)Toll receptors in Drosophila were discovered first, and shown to confer resistance to bacteria

25、and fungi by regulating the expression of anti-microbial peptides.Toll family of receptors is evolutionarily ancient10The toll like receptors in humansNon-specialized cells can detect and respond to infection by recognizing conserved motifs of microbes using TLRs The effects of bacterial LPS on macr

26、ophages are mediated by CD14 binding to TLR-4TLRs transmit signals about microbial constituents detected to the nucleus, thus regulating the type of genes expressed, and the subsequent responseContributions of innate immunity to adaptive immune responsesEnhance Antigen PresentationUpregulateCo-stimu

27、latoryMoleculesIncreaseCytokineproductionsActivatePhagocytosisPRR ligands shape adaptive T cell immunity through direct and indirect effects on DCsImmunity 33, October 29, 2010 Activation of Toll-like receptors triggers the production of pro-Inflammatory cytokines and chemokines, and the expression

28、of co-stimulatory moleculesNature 442, 39-44, 2006NLR: nucleotide binding and oligomerization domain (NOD)-like receptorNature Reviews Immunology 6, 9-20, 2006Cellular location of TLRs and NOD1 and NOD2most Gram-negativespecific Gram-positive bacteriaall types of PGNImmunity, 27,549-559, 2007 Model

29、for PGN Recognition by NOD1 and NOD2Role of NOD1 and NOD2 in Host Defense Mice with a targeted deletion of the Nod1 gene display an increased susceptibility to Helicobacter pylori (Nat. Immunol. 2004). Activation of NOD1 stimulates the production of chemokines and the recruitment of neutrophils in v

30、ivo (J.Exp. Med. 2006). NOD1 has been implicated in priming antigen-specific T cell responses, thereby contributing to the onset of adaptive immunity (Immunity. 2007). Increased bacterial burdens were observed in Nod2-/- mice infected orally, but not through the intravenous and intraperitoneal route

31、s, with Listeria monocytogenes (Science, 2005). NOD1 and NOD2 may perform unique and critical antibacterial functions in intestinal cells such as regulation of antimicrobial peptides (Science, 2005; Nat.Genet 2006).52RIG-I樣受體：樣受體： RIG-I-like receptors, RLRs識別細胞質(zhì)中的病毒RNARIG-IMDA-5LGP-2Bruce A. Beutler

32、Jules A. Hoffmann Ralph M. SteinmanThe Nobel Prize in Physiology or Medicine 2011Bruce A. Beutler and Jules A. Hoffmann for their discoveries concerning the activation of innate immunity Ralph M. Steinman for his discovery of the dendritic cell and its role in adaptive immunityComplement SystemHisto

33、ryDiscovered in 1894 byJules Bordet It represents lytic activity of fresh serumThe activity of blood serum thatcompletes the action of antibody Its lytic activity destroyedwhen heated at 56 for 30 minComplement functions Host benefit: Opsonization to enhance phagocytosis Phagocyte attraction and act

34、ivation Lysis of bacteria and infected cells Regulation of antibody responses Clearance of immune complexes Clearance of apoptic cells Host detriment: Inflammation, anaphylaxis Activated component are usually over-lined: e.g. C1qrs When enzymatically cleaved, the larger moiety, binds to the activati

35、on complex or membrane and the smaller peptide is released in the microenvironment Letter “b” is usually added to the larger, membrane-binding, peptide “a” to the smaller peptide (e.g., C3b/C3a, C4b/C4a, C5b/C5a), EXCEPT C2 (the larger, membrane-binding moiety is C2a; the smaller one is C2b)Pathways

36、 of complement activationCLASSICALPATHWAYALTERNATIVEPATHWAYactivationof C5LYTIC ATTACKPATHWAYantibodydependentLECTINPATHWAYantibodyindependentActivation of C3 andgeneration of C5 convertaseComponents of the Classical PathwayC4C3C1 complexCa+C1rC1sC1qFigure 2-21Binds to antibody:antigen complexC1q bi

37、nds to antibody:antigen complexes, thus it recruits complement to antigen tagged by antibodyFigure 7.30Figure 2-22For MB lectin MASP1/2cleave C4The rest is the sameComplement activation is a proteolytic cascade, in which one protease activates by proteolysis the next proteaseZymogen= inactive enzyme

38、 that is activated by proteolysisComponents of mannose-binding lectin (MBL) pathwayC4MBLMASP1MASP2MASP2: mannan-binding lectin serine peptidase 2Figure 2-24Mannose binding lectin is an innate recognition molecule that recruits complementMannose-binding lectin pathwayC4MBLC4bC4aC4bC4b2a is C3 convert

39、ase; it will lead to the generation of C5 convertaseMASP1MASP2Components of thealternative pathwayC3DPSpontaneous C3 activationC3H2OiDGeneration of C3 convertaseC3iBb complex has a very short half lifebC3C3abComplement activation includes feed forward amplification stepsMacrophages, neutrophils and

40、other white blood cells carry C3b receptors that they use to rapidly phagocytose and destroy microbes.C3b regulation on self and activator surfacesC3bC3bC3bC5-convertase of the two pathwaysC3bC3bC5-convertase of the Alternative PathwayC4bC3b C5-convertase of the Classical and lectin PathwaysGenerati

41、on of C5 convertase leads to the activation of the Lytic pathwayLytic pathwayLytic pathway:insertion of lytic complex into cell membraneC5b C6C7 C9C9C9C9C9C9C9C9C9Biological effects of C5aOpsonization and phagocytosis三條激活途徑的主要不同點補體的生物學(xué)作用補體的生物學(xué)作用溶菌及溶靶細胞作用：溶菌及溶靶細胞作用： G(-)菌、菌、RBC、粒細胞、血小板和病毒感染的細胞等、粒細胞、血小板和病毒感染的細胞等調(diào)理作用：調(diào)理作用：C3b、C4b以及以及 iC3b 氨基端與靶細胞結(jié)合，羧基端與相應(yīng)受體結(jié)合氨基端與靶細胞結(jié)合，羧基端與相應(yīng)受體結(jié)合清除免疫復(fù)合物：清除免疫復(fù)合物：粘附到帶有粘附到帶有C3b受體的細胞表面（主要是受體的細胞表面（主要是 紅細胞），最終達到清除免疫復(fù)合物的作用紅細胞），最終達到清除免疫復(fù)合物的作用炎癥介質(zhì)作用：炎癥介質(zhì)作用： 激肽樣作用：激肽樣作用：C2a、C3a、C4a,增加血管通透性增加血管通透性 過敏毒素作用：過敏毒素作