Lecture1-免疫學(xué)概述.ppt

1、分子免疫學(xué)概述,吉林大學(xué)畜牧獸醫(yī)學(xué)院 2011.09,The Origin of Immune Concept,The term “Immunity” = Latin word “Immunitas” = Protection from legal prosecution (Roman senators) Biological definition = Protection from infectious diseases 2.The concept of immunity = existed in ancient Greek & Chinese = the experienced view,

2、“天花”又名痘瘡,十六世紀(jì)下半葉（明代隆慶年間1567-1572）正式發(fā)明了人痘接種術(shù)，十七世紀(jì)普遍推廣。,The medical view of immunity = Edward Jenner (1796) Observation = Milkmaids generally get No Smallpox Hypothesis = Pus from vaccinia (cowpox) = Protect milkmaids from smallpox Test = Inoculate materials from cowpox pus = Protect a young boy from

3、smallpox (Protective immunity),The vaccination against smallpox,Exudate from a cowpox pustule on the hand of milkmaid Sarah Nelmes was inserted into scratches on the arms of James Phipps, May 14, 1796.,1796年，英國(guó)人Edward Jenner發(fā)明牛痘苗預(yù)防天花（cowpox vaccine）。,Edward Jenner,Eradication of smallpox,4.The conce

4、pt of “Immunity” developed gradually over time through many scientific findings: = Robert Koch (1905 Nobel Laureate) = Infectious diseases caused by microorganisms = Louis Pasteur = Vaccines against cholera & rabies = These clinical successes = The search of underlying mechanism of “Protection of In

5、fectious Diseases”,研制出多種減毒疫苗（attenuated vaccine）,用于預(yù)防雞霍亂,炭疽桿菌,狂犬病等疾病。,Louis Pasteur,1880年，雞霍亂弧菌減毒疫苗,Vaccines for common infectious diseases,b型流感嗜血桿菌,破傷風(fēng),百日咳,風(fēng)疹,腮腺炎,麻疹,脊髓灰質(zhì)炎,乙肝,白喉,Still no effective vaccines for many infectious microbes, e.g., HCV, HIV, Dengue virus.etc,細(xì)胞免疫和體液免疫學(xué)派的形成： (19世紀(jì)后葉-20世紀(jì)中葉

6、) 免疫學(xué)重大學(xué)說和理論：克隆選擇學(xué)說(1957)；免疫網(wǎng)絡(luò)學(xué)說(1974) 對(duì)免疫系統(tǒng)的全面認(rèn)識(shí)：發(fā)現(xiàn)各種免疫器官及免疫細(xì)胞,Descriptive Science” = “Experimental Science”,(1) 細(xì)胞免疫學(xué)說 (cellular immunity),Neutrophil,梅契尼可夫,1880s- Metchnikoff discovered phagocytic cells that ingest microbes and particles,cells conferred immunity,免疫應(yīng)答機(jī)制的研究:,1. The Discovery of anti

7、body functions in 1897 2. The Nobel Laureate in Medicine 1908,Adopted from Nature Immunology, July 2008,liquid of blood conferred immunity,發(fā)現(xiàn)抗體能清除各種病原微生物或者能中和細(xì)菌毒素。,(2) 體液免疫學(xué)說 (humoral immunity),Paul Ehrlich: One of the fathers of humoral adaptive immunity,Q: Which confers immunity cells or serum? A:

8、 Both cells and serum contribute to immunity!,MacFarlane Burnet （1899-1985）,克隆選擇學(xué)說 clonal selection theory,體內(nèi)事先就存有能識(shí)別各種抗原的細(xì)胞克隆(clone)，每一細(xì)胞表面均有對(duì)特定抗原的受體，能與相應(yīng)抗原結(jié)合而識(shí)別它們?？乖淖饔迷谟谶x擇與其相應(yīng)的細(xì)胞克隆與其受體結(jié)合后，引起細(xì)胞的增殖分化，產(chǎn)生免疫應(yīng)答，產(chǎn)生大量抗體（即免疫球蛋白）。,抗體形成理論 -克隆選擇學(xué)說,體內(nèi)存在無(wú)數(shù)抗原特異性淋巴細(xì)胞克隆 胚胎期與自身成分反應(yīng)的淋巴細(xì)胞被“禁忌”形成耐受 出生后淋巴細(xì)胞遇到相應(yīng)抗原發(fā)生特異應(yīng)

9、答，并形成記憶 禁忌細(xì)胞突變可導(dǎo)致自身免疫,Advances in technology (e.g., Cell culture, Monoclonal Ab, Flow cytometry, Genetic engineeringetc) have facilitated our understanding of the immune system and its functions. “,(1)免疫學(xué)理論研究 抗體多樣性和特異性的遺傳學(xué)基礎(chǔ) T細(xì)胞抗原受體的基因克隆 免疫遺傳學(xué)和MHC限制性的發(fā)現(xiàn) 細(xì)胞因子及其受體 信號(hào)轉(zhuǎn)導(dǎo)的研究 危險(xiǎn)信號(hào)學(xué)說,(2)免疫學(xué)應(yīng)用研究： 基因工程疫苗 基因工

10、程制備重組細(xì)胞因子 免疫細(xì)胞治療 治療性抗體,免疫（immunity) 傳統(tǒng)概念指免除疫病、免除感染，指機(jī)體抗感染的防御能力。 現(xiàn)代概念指機(jī)體對(duì)“自己”或“非己”的識(shí)別并排除“非己”的功能。,免疫的基本功能,免疫系統(tǒng) (immune system)：機(jī)體執(zhí)行免疫功能的組織、器官、細(xì)胞和分子構(gòu)成免疫系統(tǒng)。,The four kinds of pathogens that cause human disease,常見的病原微生物,Overview of immune responses,固有免疫 （innate immunity） 是機(jī)體抵御病原微生物入侵的第一道防線，并啟動(dòng)和參與適應(yīng)性免疫應(yīng)答。

11、 天然免疫（natural immunity)或非特異性免疫(nonspecific immunity)，是個(gè)體出生時(shí)就具有的免疫力，通過遺傳獲得，是生物在長(zhǎng)期進(jìn)化過程中逐漸形成的，其針對(duì)外來異物的范圍廣，反應(yīng)迅速，其應(yīng)答模式和強(qiáng)度不因與病原微生物的反復(fù)接觸而改變。,固有免疫系統(tǒng)的組成,屏障 細(xì)胞 分子,皮膚黏膜屏障：物理、化學(xué)、微生物 血-腦屏障、血-胸腺屏障 血-胎屏障、氣-血屏障,巨噬細(xì)胞、中性粒細(xì)胞、樹突狀細(xì)胞、T 細(xì)胞、NK細(xì)胞、NKT細(xì)胞、B1細(xì)胞、肥大細(xì)胞、嗜堿性粒細(xì)胞和嗜酸性粒細(xì)胞等。,抗菌肽、溶菌酶、急性期蛋白、補(bǔ)體、細(xì)胞因子和黏附分子、,Epithelial barrier

12、s prevent the entry of microbes,固有免疫細(xì)胞,Phagocyte NK ILLs（固有樣淋巴細(xì)胞） DC MC Basophil Eosinophil, T細(xì)胞 NKT細(xì)胞 B1細(xì)胞,Monocyte-macrophage Neutrophil,肺部巨噬細(xì)胞吞噬大腸桿菌,Phagocytosis by innate immunity,固有性免疫分子,指體表分泌液以及血漿和其它體液中能夠識(shí)別或攻擊病原體的可溶性分子。,抗菌肽 antimicrobial peptides 溶菌酶 lysozyme 急性期蛋白(acute phase proteins, APP) 脂

13、多糖結(jié)合蛋白（LBP） 血清淀粉樣蛋白（SAP） 甘露糖結(jié)合蛋白（MBP） C反應(yīng)蛋白等（CRP） 補(bǔ)體 細(xì)胞因子和黏附分子,Complement activation pathways,Elie Mechnikoff:The Pioneer of Innate Immunity,1. The Discovery of Phagocytes & Phagocytosis 2. The Nobel Laureate in Medicine 1908,Adopted from Nature Immunology, July 2008,The development of modern Immuno

14、logy in 20th century mainly centers on understanding the Adaptive Immune System.,Charles A. Janeway, M.D. Yale Univ.,The “Renaissance” of innate immunity,In 1989, Janeway = Immune recognition of microbes = Detection of conserved molecular patterns, referred to PAMPs (Pathogen-Associated Molecular Pa

15、tterns) with features: 1. Invariant among a given class of microbes. 2. Have essential roles in microbial physiology. 3. Recognized by receptors of the innate immune system, called PRRs (Pattern-Recognition Receptors). 4. Innate immunity regulates adaptive immunity,Julie A. Hoffmann, Ph.D. Strasbour

16、g, France,The “Renaissance” of innate immunity,In 1996, Hoffmanns group Toll functions as a PRR in Drosophila,Key concepts in innate immunity,1. The innate immune system mainly recognizes common structures shared by classes of microbes, = Pathogen Associated Molecular Patterns (PAMPs), e.g., LPS, Pe

17、ptidoglycan, Microbial DNA & RNA. 2. Host receptors that recognize PAMPs are called Pattern- Recognition Receptors (PRRs), which are encoded in “Germline” DNA= limited Diversity. 3. Innate immunity not only provide the first line of defenses but link to the program of adaptive immunity. 4. PRRs may

18、also recognize components from injured or dead host cells = Autoimmune diseases,Pathogen-AssociatedMolecularPatterns(PAMP),是病原微生物（尤其是原核生物）表面存在一些人體所沒有的，但可為許多相關(guān)微生物所共享、結(jié)構(gòu)恒定、進(jìn)化保守的分子結(jié)構(gòu)。,損傷相關(guān)分子模式 （damage-associated molecular patterns，DAMPs）,機(jī)體自身細(xì)胞所釋放的內(nèi)源性分子，即內(nèi)源性危險(xiǎn)信號(hào)，來源于受損或壞死組織和某些激活的免疫細(xì)胞。主要有HMGB1、熱體克蛋白等。,PA

19、MP vs DAMP,Sterile inflammation,conserved microbial motifs VS non-microbial signals,Locations of Different PRRs,Body fluids -Soluble PRRs Cellular PRRs - Cell surface - Endosomes - Cytosol,Toll-like Receptors,MyD88-Dependent and independent Signaling,NLRs are cytoplasmic bacterial sensors that activ

20、ate inflammasomes,1,Viral Pattern Recognition Receptors: Signaling and Consequences,Interaction between innate and& adaptive immunity,1. Innate immunity = Ag presentation (by Dendritic cells) 2. Adaptive immunity = Ag recognition (by T & B lymphocytes),適應(yīng)性免疫 （adaptive immunity）,是機(jī)體獲得性、抗原特異性、抵抗病原微生物感

21、染的高效防御機(jī)制。 獲得性免疫（acquired immunity)或特異性免疫(specific immunity)，是個(gè)體出生后，在環(huán)境中受抗原刺激所產(chǎn)生的免疫力，針對(duì)特定抗原，有特異性、多樣性、記憶性和耐受性。 1) 特異性，對(duì)某個(gè)特定的異物性抗原能引起特異性免疫應(yīng)答；指抗原特異性。 2) 多樣性，機(jī)體可針對(duì)環(huán)境中多種多樣的抗原，分別建立起不同的特異性免疫應(yīng)答；多樣性是特異性產(chǎn)生的基礎(chǔ)。 3) 記憶性，當(dāng)異物抗原再次入侵時(shí)，可產(chǎn)生快而強(qiáng)的再次免疫應(yīng)答效應(yīng)；記憶性淋巴細(xì)胞。4) 耐受性，正常情況下，免疫系統(tǒng)對(duì)自身成分有保護(hù)性的免疫耐受；,抗原決定簇Antigenic determinant

22、，AD,抗原分子表面具有特殊立體構(gòu)型和免疫活性的化學(xué)基團(tuán)稱為抗原決定簇或抗原決定基。由于抗原決定簇通常位于抗原分子表面，因而又稱為抗原表位(epitope)。 抗原決定簇抗原決定基 抗原表位 抗原決定簇決定抗原的特異性，即決定抗原與抗體發(fā)生特異性結(jié)合的能力（實(shí)際是抗原決定簇與抗體的結(jié)合）。,AD的數(shù)目、性質(zhì)和空間構(gòu)象決定抗原特異性 抗原以AD與相應(yīng)抗原受體及抗體特異性結(jié)合,APC加工處理的抗原種類: 外源性抗原(exogenous antigen): 通過吞噬或吞飲等作用被APC從細(xì)胞外攝入的抗原，以抗原肽-MHC I I類分子復(fù)合物形式提呈給CD4+T細(xì)胞 。 內(nèi)源性抗原(endogenou

23、s antigen): 細(xì)胞內(nèi)合成的抗原，以抗原肽-MHC I類分子復(fù)合物形式提呈給CD8+T細(xì)胞 。,外源性抗原加工，處理及提呈,APC 攝取的外源性抗原在內(nèi)體中降解成肽，與 MHC類分子(在內(nèi)質(zhì)網(wǎng)合成) 結(jié)合后表達(dá)于細(xì)胞表面。外源性抗原加工中需要 Ii 鏈和 HLA-DM 分子的參與。Ii 鏈 與 MHC類分子的轉(zhuǎn)運(yùn)有關(guān)，并通過 CLIP 封閉 MHC類分子的肽結(jié)合部位，阻止 MHC-類分子在內(nèi)質(zhì)網(wǎng)中與內(nèi)源性抗原肽結(jié)合。HLA-DM 分子促使 CLIP 從 MHC類分子肽結(jié)合區(qū)解離，有利抗原肽與 MHC類分子結(jié)合。,內(nèi)源性抗原加工，處理及提呈,內(nèi)源性抗原經(jīng)蛋白酶體降解成肽，通過抗原加工相關(guān)

24、轉(zhuǎn)運(yùn)體(TAP1、TAP2)轉(zhuǎn)運(yùn)進(jìn)入內(nèi)質(zhì)網(wǎng)，與 MHC類分子(在內(nèi)質(zhì)網(wǎng)合成)結(jié)合成肽-MHCI類復(fù)合物，通過高爾基體表達(dá)于細(xì)胞表面。 TAP是內(nèi)質(zhì)網(wǎng)上的異源性二聚體，由TAP-1及TAP-2基因編碼胞漿中蛋白酶體（proteasomes, 核心成分為低分子量多肽LMP,細(xì)胞被病毒感染后出現(xiàn)的病毒蛋白，基因突變后產(chǎn)生的腫瘤抗原,THE ADAPTIVE IMMUNE RESPONSE,Antibody-Mediated Immunity (AMI) Involves B lymphocytes, plasma cells and antibodies Humoral immunity Name

25、derives from antibodies found in body fluids (humors - old medical term) Cell-Mediated Immunity (CMI) Involves T lymphocytes, antigen-presenting cells and MHC (major histocompatibility complex) molecules Cellular immunity,Types of adaptive immunity,1. Humoral immunity = Molecules in body fluid, e.g.

26、 Antibody (Ab) = Key player = B cells = Target extracellular microbes & toxins 2. Cell-mediated immunity = Key player = T cells = regulate other immune cells = Target intracellular microbes, e.g. viruses, bacteria,For innate immunity, it also includes Humoral & Cellular components for immune defense

27、,1、抗原提呈與識(shí)別階段（感應(yīng)階段）： 2、活化、增殖、分化階段（反應(yīng)階段）： T細(xì)胞活化、增殖分化為效應(yīng)T細(xì)胞； B細(xì)胞活化、增殖分化為漿細(xì)胞； 部分細(xì)胞發(fā)育為記憶細(xì)胞。 3、效應(yīng)階段： 效應(yīng)T細(xì)胞對(duì)抗原的清除； 漿細(xì)胞分泌抗體清除抗原。,免疫應(yīng)答的三個(gè)階段,Overview of adaptive immune responses,CELL-MEDIATED IMMUNITY (CMI),Directed against intracellular microorganisms Non-phagocytic cells and phagocytic cells T-lymphocytes

28、(T cells) Differentiate into effector cells following antigen presentation by antigen presenting cells (APCs) Functional types of T cells Helper (CD4 T cells) TH1 and TH2 cells Cytotoxic (CD8 T cells),T cells develop in the thymus,TSC,CD4 RTE,TCR,TCR,CD8,CD4,b-selection,Positive selection,Negative s

29、election,Functional maturation,TCR-b rearrangement,TCR-a rearrangement,CD8 RTE,Development of Thymocytes,Double negative,Double positive,Single positive,T cells undergo further differentiation in secondary lymphoid tissues after encounter with antigen,Only a small fraction of naive T cells (mature T

30、 cells before they encounter antigen) survives the positive and negative selection, and leaves the thymus. Mature naive T cells can re-circulate between blood and lymphoid tissues for many years (in contrast to B cells, which have shorter life span). In secondary lymphoid tissues, T cells accumulate

31、 in T cell areas, where they become activated by their specific antigens. Encounter with antigen induces the final stage of T cell development: their differentiation into effector T cells. Some effector T cells stay in the lymphoid tissues (CD4-TH2 cells), while others migrate to site of infection (

32、CD8 and CD4-TH1 cells).,T細(xì)胞受體復(fù)合物 由TCR和CD3組成。前者識(shí)別和結(jié)合抗原肽, 后者將TCR獲得的抗原信號(hào)傳遞至細(xì)胞內(nèi)。,T細(xì)胞對(duì)抗原的識(shí)別,APC,T細(xì)胞,T細(xì)胞活化的雙信號(hào)刺激 第一信號(hào)：TCR對(duì)MHCII抗原肽復(fù)合物的識(shí)別，CD3分子將第一信號(hào)傳遞到細(xì)胞內(nèi)。 第二信號(hào)：CD28識(shí)別專職APC上的B7分子,又稱協(xié)同刺激信號(hào)。,Effector T cells,In contrast to terminally differentiated B cells (plasma cells), there are several types of terminall

33、y differentiated effector T cells. CD8 T cells Cytotoxic T cells (recognize MHC class I molecules) CD4 T cells,TH1 helper cells (activate macrophages) TH2 helper cells (induce differentiation of B cells into plasma cells and production of antibodies),Activation (cytokines),(recognize MHC II molecule

34、s),The immune system is maintained in a carefully regulated balance between the two polarised control arms, Th1 (cellular immunity) and Th2 (humoral immunity).,In disease states the balance is skewed. multiple sclerosis, rheumatoid arthritis and type I diabetes, have a Th1 bias, whereas cancer patie

35、nts have a Th2 bias.,Th1 and Th2 Cells Do not Represent All CD4+ Cells,More T helper subsets,Th3: TGF-producing CD4 T cells Tr1: IL-10-producing CD4 T cells Th9: IL-9-producing CD4 T cells Tfh: follicular helper T cells, located in the follicular regions of lymph nodes and spleen,follicular Th1/Th2/

36、Th17 cells,ANTIBODY-MEDIATED (HUMORAL) IMMUNITY,Directed against extracellular microorganisms and toxins B-lymphocytes (B cells) Differentiate into plasma cells which produce antibodies Function as antigen-presenting cells (APCs) Classification of Antibodies (Immunoglobulins) Immunoglobulin M (IgM)

37、Immunoglobulin G (IgG) Immunoglobulin A (IgA) Immunoglobulin D (IgD) Immunoglobulin E (IgE),抗體的功能 V區(qū)的功能 識(shí)別并特異性結(jié)合抗原 單體（IgG, IgE) 2價(jià) 二聚體(分泌型IgA) 4價(jià) 五聚體(IgM) 10價(jià) 中和效應(yīng) 中和毒素和病毒 與Ag結(jié)合 促吞噬細(xì)胞吞噬,抗體的結(jié)合價(jià),實(shí)際意義,C區(qū)的功能 1.激活補(bǔ)體系統(tǒng) Ab(IgM、IgG) + Ag C1q 補(bǔ)體經(jīng)典途徑 IgG4、IgA和 IgE的凝聚物 補(bǔ)體旁路途徑 2.介導(dǎo)免疫細(xì)胞活性 (1)調(diào)理作用（opsonization）：I

38、gG + 抗原(顆粒性) FcR（單核、巨噬細(xì)胞及中性粒細(xì)胞） 促吞噬細(xì)胞吞噬； (2)ADCC：IgG + 抗原(靶細(xì)胞) Fc R（NK 細(xì)胞） 殺傷靶細(xì)胞； (3)介導(dǎo)超敏反應(yīng)：型、型和型超敏反應(yīng)。 3.穿越胎盤和粘膜,Antibody-Dependent Cellular Cytotoxicity (ADCC),Th2與B細(xì)胞的相互作用，獲得第二信號(hào)：協(xié)同刺激信號(hào),CD40-CD40L,活化的Th2細(xì)胞分泌細(xì)胞因子及表達(dá)CD40L，輔助B細(xì)胞活化,第二信號(hào)（Th細(xì)胞信號(hào)） 有二種方式 （1）Th細(xì)胞-B細(xì)胞間接觸作用：CD40L-CD40等 （2）Th細(xì)胞分泌細(xì)胞因子：IL-4、5、6

39、等,胸腺依賴性抗原（TD-Ag）,Specificity, Memory, and Homeostasis of Adaptive Immunity,體液免疫應(yīng)答一般規(guī)律,多克隆抗體(polyclonal antibody，PcAb )：采用傳統(tǒng)的免疫方法，將抗原物質(zhì)經(jīng)不同的途徑進(jìn)入動(dòng)物體內(nèi)，經(jīng)數(shù)次免疫后采取動(dòng)物血液，分離出血清，由此獲得的抗血清即為多克隆抗體。用天然的抗原物質(zhì)免疫動(dòng)物，刺激多個(gè)B細(xì)胞克隆所獲得的免疫血清（含多種特異性抗體）。 單克隆抗體(Monoclonal Antibody，McAb):由一個(gè)B細(xì)胞分化增殖的子代細(xì)胞產(chǎn)生的針對(duì)單一抗原決定簇的抗體，稱單克隆抗體。 由一個(gè)B細(xì)

40、胞克隆產(chǎn)生。 識(shí)別一種抗原表位。 高度均一（結(jié)構(gòu)、特異性）。 雜交瘤技術(shù)制備。 基因工程抗體：利用基因工程技術(shù)來制備的抗體分子稱為基因工程抗體，是分子水平的抗體。,US和EU所批準(zhǔn)的治療性抗體,鼠源性單克隆抗體將逐漸被人源化抗體所替代：鼠源性單克隆抗體與人補(bǔ)體成分結(jié)合能力低，CDC作用相應(yīng)較弱，對(duì)腫瘤細(xì)胞的殺傷能力較弱；它與NK等免疫細(xì)胞表面Fc受體親和力弱，介導(dǎo)的 ADCC作用較弱；鼠源抗體在人血循環(huán)中的半衰期短，它發(fā)揮ADCC與CDC作用的時(shí)間較短；鼠單克隆抗體具有免疫原性，宿主易產(chǎn)生抗抗體引起過敏反應(yīng)。,抗體人源化改造及人源抗體制備,人-鼠嵌合抗體：應(yīng)用基因工程技術(shù)將小鼠單克隆抗體的恒定

41、區(qū)用人源抗體恒定區(qū)代替而拼接成嵌合抗體。 改型抗體如CDR移植、SDR移植：用鼠單克隆抗體的CDR、SDR移植到人源抗體可變區(qū)，替代人源抗體CDR、SDR。 表面氨基酸殘基人源化,抗體人源化的主要技術(shù),macrophage,Activated T cell,a,A,D,P56 B C58,B,C,NH2,COOH,IL-2,Cytockines are low-molecular-weight regulatory proteins or glycoproteins secreted by white blood cells and various cells (vascular endothelial cell, epidermic cell and fibroblast ) in body in response to a number of stimuli.,Cytokine,Biological effects,Cytokine imbalance during inflammation,細(xì)胞因子的研究熱點(diǎn) 1、新細(xì)胞因子的基因克隆化 2、細(xì)胞因子受體的基因克隆化 3、細(xì)胞因子信號(hào)轉(zhuǎn)導(dǎo)機(jī)制 4、新一代細(xì)胞因子：高活性，多功能，低毒副作用，長(zhǎng)半衰期