微生物感念感染的预防原则.pptx

Medical MicrobiologyDepartment of Microbiology,HMUDepartment of Microbiology,HMU第一篇 微生物学基础第9章 微生物感染的预防原则微生物学教研室微生物学教研室 吴凌吴凌提纲n n微生物感染的预防原则微生物感染的预防原则uu特异性免疫的分类特异性免疫的分类 生物制品生物制品n n细菌感染的特异性预防细菌感染的特异性预防uu人工主动免疫常用的生物制品人工主动免疫常用的生物制品uu人工被动免疫的生物制品人工被动免疫的生物制品n n病毒感染的特异性预防病毒感染的特异性预防uu人工主动免疫预防人工主动免疫预防uu人工被动免疫预防人工被动免疫预防n n真菌感染的预防原则真菌感染的预防原则特异性免疫的分类n n自然免疫uu自然自然主动主动免疫：隐性或显性感染免疫：隐性或显性感染uu自然自然被动被动免疫：通过胎盘或初乳获得母体抗体免疫：通过胎盘或初乳获得母体抗体n n人工免疫uu人工人工主动主动免疫：接种疫苗或类毒素等免疫：接种疫苗或类毒素等uu人工人工被动被动免疫：注射抗毒素或丙种球蛋白等免疫：注射抗毒素或丙种球蛋白等人工免疫 artificial immunizationn n用人工的方法给机体输入抗原性物质（如疫苗、类毒素等）或直接输入免疫效应分子（如抗体、细胞因子等），使机体获得特异性免疫力的方法n n人工主动免疫 artificial active immunizationartificial active immunizationn n人工被动免疫 artificial passive immunizationartificial passive immunization人工免疫n n人工自动免疫人工自动免疫 artificial active artificial active immunizationimmunizationuu疫苗（疫苗（vaccinevaccine）uu类毒素类毒素n n人工被动免疫人工被动免疫 artificial passive artificial passive immunizationimmunizationuu抗毒素抗毒素uu抗菌血清抗菌血清uu血清丙种球蛋白血清丙种球蛋白人工自动与被动免疫比较区区 别别 点点人工自动免疫人工自动免疫人工被动免疫人工被动免疫免疫物质免疫物质接种次数接种次数免疫力出现时间免疫力出现时间免疫力维持时间免疫力维持时间用途用途抗原抗原1 3 1 3 次次慢（慢（2 4 2 4 周）周）长（数月长（数月 数年）数年）多用于预防多用于预防抗体或细胞因子抗体或细胞因子1 1 次次快（立即出现）快（立即出现）短（短（2 3 2 3 周）周）用于治疗或应急预防用于治疗或应急预防生物制品 biological productn n人工主动免疫生物制品人工主动免疫生物制品uu疫苗疫苗uu类毒素类毒素n n人工被动免疫生物制品人工被动免疫生物制品uu抗毒素抗毒素uu丙种球蛋白丙种球蛋白细菌感染的特异性预防疫苗（vaccine）n n减毒活疫苗减毒活疫苗（attenuated live vaccineattenuated live vaccine）uu卡介苗（卡介苗（BCGBCG）n n灭活疫苗灭活疫苗（inactivated vaccineinactivated vaccine）uu伤寒沙门菌与甲、乙型副伤寒沙门菌混合的三联疫苗伤寒沙门菌与甲、乙型副伤寒沙门菌混合的三联疫苗n n亚单位疫苗（亚单位疫苗（subunit vaccinesubunit vaccine）n n基因工程疫苗（基因工程疫苗（gene engineered vaccinegene engineered vaccine）n n核酸疫苗（核酸疫苗（nucleic acid vaccinenucleic acid vaccine）类毒素（toxoid）n n细菌细菌外毒素外毒素经经0.40.4甲醛液甲醛液处理后，其毒性消失而处理后，其毒性消失而仍保留抗原性的生物制品仍保留抗原性的生物制品n n常用的类毒素常用的类毒素uu白喉类毒素白喉类毒素uu破伤风类毒素等破伤风类毒素等uu白、百、破三联疫苗白、百、破三联疫苗人工被动免疫生物制品n n抗毒素（antitoxin）uu通常是用细菌通常是用细菌类毒素类毒素给马多次注射后，取其免给马多次注射后，取其免疫血清提取疫血清提取免疫球蛋白免疫球蛋白精制而成精制而成n n常用uu破伤风抗毒素破伤风抗毒素uu白喉抗毒素白喉抗毒素n n免疫球蛋白（immunoglobulin）病毒感染的特异性预防人工主动免疫病毒疫苗 n n减毒活疫苗（减毒活疫苗（attenuated live vaccineattenuated live vaccine）n n灭活疫苗（灭活疫苗（inactivated vaccineinactivated vaccine）n n亚单位疫苗（亚单位疫苗（subunit vaccinesubunit vaccine）n n基因工程疫苗（基因工程疫苗（gene engineered vaccinegene engineered vaccine）uu基因工程亚单位疫苗（基因工程亚单位疫苗（gene engineered subunit vaccinegene engineered subunit vaccine）uu基因工程载体疫苗（基因工程载体疫苗（gene engineered vectored vaccinegene engineered vectored vaccine）uu基因缺失活疫苗（基因缺失活疫苗（gene deleted live vaccinegene deleted live vaccine）uu核酸疫苗（核酸疫苗（nucleic acid vaccinenucleic acid vaccine）。）。n n合成肽疫苗（合成肽疫苗（synthetic peptide vaccinesynthetic peptide vaccine）n n抗独特型疫苗（抗独特型疫苗（anti-idiotype vaccineanti-idiotype vaccine）活疫苗（Living vaccine）n n减毒活疫苗n n基于基因工程技术的新型活疫苗uu遗传重组活疫苗uu基因缺失活疫苗uu载体活疫苗减毒活疫苗(Attenuated vaccine)n n自然或人工选择法（如自然或人工选择法（如TsTs株）对人低毒或无毒的株）对人低毒或无毒的变异株，如脊灰、流感、麻疹的减毒株变异株，如脊灰、流感、麻疹的减毒株n n优点：模拟自然感染，免疫效果好，局部优点：模拟自然感染，免疫效果好，局部IgAIgA。n n理论上的缺点，实际工作中少见理论上的缺点，实际工作中少见uu变异株可能回复到有毒力的野生株变异株可能回复到有毒力的野生株uu如果机体免疫缺陷，减毒株仍可能引起感染或并发症如果机体免疫缺陷，减毒株仍可能引起感染或并发症uu可能激活机体内其他病毒的感染可能激活机体内其他病毒的感染uu减毒活苗可能引起持续感染减毒活苗可能引起持续感染n n成功的范例：成功的范例：19611961年我国应用脊灰疫苗，脊灰发年我国应用脊灰疫苗，脊灰发病率大幅度下降。病率大幅度下降。19801980年天花病毒灭绝年天花病毒灭绝遗传重组疫苗n n将野毒株表面抗原基因与弱毒株其他基因组合而获得减毒活病毒n n适用于基因组分节段双链RNA病毒，如流感病毒、轮状病毒等基因缺失活疫苗n n利用DNA重组技术，定向缺失病毒基因组的某一区段，使病毒丧失毒力而保留增殖能力和免疫原性n n优点：疫苗株的遗传背景清楚，不易突变回到野毒株载体活疫苗n n利用DNA重组技术，将编码病毒抗原的基因插入到另一无毒力的载体病毒，使之高效表达n n易建立多价疫苗n n载体病毒常用的有痘苗病毒、腺病毒、HSV-1灭活疫菌（Killed vaccine）n n灭活全病毒疫苗n n亚单位疫苗n n合成肽病毒疫苗n n基因工程疫苗n n独特型病毒疫苗n n核酸疫苗灭活全病毒疫苗n n物理或化学方法灭活病毒。适用烈性或易变异病毒如乙脑病毒、狂犬病病毒、流感病毒n n优点：生产简单、易保存运输n n缺点uu需要大量培养病毒，成本高需要大量培养病毒，成本高uu无局部抗体，不激活无局部抗体，不激活CTLCTL，可激活，可激活T TDTHDTHuu甲醛灭活的麻疹病毒和甲醛灭活的麻疹病毒和RSVRSV疫苗可加重疾病，疫苗可加重疾病，机制不详机制不详亚单位疫苗（Subunit）n n种类uu化学方法制备：如化学方法制备：如HBsAgHBsAg和流感和流感HAHAuu基因工程亚单位疫苗基因工程亚单位疫苗n n优点uu不含病毒核酸，仅有能诱导中和抗体的衣壳不含病毒核酸，仅有能诱导中和抗体的衣壳蛋白或包膜表面抗原。免除了回复突变和交蛋白或包膜表面抗原。免除了回复突变和交叉复活的可能叉复活的可能uu消除肿瘤病毒的潜在的致癌作用消除肿瘤病毒的潜在的致癌作用合成肽病毒疫苗n n人工合成病毒保护性抗原决定簇肽段n n优点uu制备容易，可大量生产，易保存，副作用少制备容易，可大量生产，易保存，副作用少n n理论与实践上的缺点uu免疫原性弱，使用时需要加佐剂。免疫原性弱，使用时需要加佐剂。uu不同肽免疫活性有差异。不同肽免疫活性有差异。uu部分肽只激发部分肽只激发B B细胞表位，缺乏激发细胞表位，缺乏激发T TH H细胞细胞的表位的表位基因工程疫苗n n利用DNA重组技术制备的生物制品。如将编码病毒特异抗原的基因用适当的载体将此基因带入大肠杆菌或真核细胞，使之表达n n研发成本高，生产成本低，下游工程复杂核酸疫苗n n将病毒基因导入DNA载体（通常是带有真核表达调控基因的质粒或病毒），将重组DNA导入机体，重组DNA可以在细胞的转录和翻译系统表达出目的蛋白n n优点：同时刺激产生体液和细胞免疫，能诱导CTL活性，易生产，易保存n n理论上缺点：安全性尚待考察n n目前仅在实验研究中，尚未投放市场独特型病毒疫苗（Idiotype）n n基于Jerne的免疫网络学说，内影像组抗体中含有与抗原一致的表位序列，又称抗独特型抗体疫苗n n特别适合于uu不能培养或培养困难、产量极低的病原体不能培养或培养困难、产量极低的病原体uu直接用病病制备有潜在危险的，如直接用病病制备有潜在危险的，如RetrovirusRetrovirusuu免疫原性弱，且不能用重组技术生产的抗原免疫原性弱，且不能用重组技术生产的抗原人工被动免疫预防n n胎盘丙种球蛋白n n人血清丙种球蛋白n n特异性免疫球蛋白uu乙型肝炎免疫球蛋白乙型肝炎免疫球蛋白真菌感染预防n n无特异性的相应疫苗无特异性的相应疫苗uu真菌的真菌的表面抗原性弱表面抗原性弱，无法制备有效的预防性疫苗，无法制备有效的预防性疫苗n n皮肤癣菌感染皮肤癣菌感染uu注意皮肤卫生；保持鞋袜清洁、干燥；避免与患者及注意皮肤卫生；保持鞋袜清洁、干燥；避免与患者及其污染的物品直接接触其污染的物品直接接触n n深部真菌感染深部真菌感染uu提高机体的免疫力提高机体的免疫力n n真菌性食物中毒真菌性食物中毒uu严禁销售和食用发霉的食品严禁销售和食用发霉的食品小结n n微生物感染的预防原则微生物感染的预防原则uu特异性免疫的分类特异性免疫的分类 生物制品生物制品n n细菌感染的特异性预防细菌感染的特异性预防uu人工主动免疫常用的生物制品人工主动免疫常用的生物制品uu人工被动免疫的生物制品人工被动免疫的生物制品n n病毒感染的特异性预防病毒感染的特异性预防uu人工主动免疫预防人工主动免疫预防uu人工被动免疫预防人工被动免疫预防n n真菌感染的预防原则真菌感染的预防原则抗病毒药物抗病毒药物（Chemotherapy）Bacteria Many antibiotics Highly selectiveViruses Use host cell metabolism Selectivity difficult ToxicityChemotherapyKey is selectivityOther problems Toxicity Rapid excretion Rapid metabolism Poor absorptionChemotherapyIdeal Drug Water soluble Chemically and metabolically stable Easily absorbed(apolar)NOTToxic Carcinogenic Allergenic Mutagenic TeratogenicChemotherapyTherapeutic index(T.I.)Minimum dose toxic to cellMinimum dose toxic to virusEffective drug:T.I.=100-1000Chemotherapy PrincipleInterfere with:A specific viral function e.g.enzyme A cellular function that the virus needs so that it cannot replicate If interfere with cellular function either:It must be crucial to virus but not the cellor Only the virus-infected cell must be killed(activation of drug in the infected cell only?)ChemotherapyViral enzymesNucleic acid polymerases DNA-dependent DNA polymerase-DNA viruses RNA-dependent RNA polymerase-RNA viruses RNA dependent DNA polymerase (RT)-Retroviruses Protease Integrase NeuraminidaseChemotherapy1962 Idoxuridine（疱疹净）（疱疹净）Pyrimidine analog Toxic Topical-Epithelial herpetic keratitis1983 Acyclovir（无环鸟苷）（无环鸟苷）Purine analog Sugar modification Chain terminator Anti-herpes Selective to virus-infected cells1990s Protease inhibitorsChemotherapyAmantadine（金刚烷胺）（金刚烷胺）:1966Rimantadine:1993Only effective against flu A(200mg/day)Marginally effective therapeutically Prophylaxis:Reduce flu by 90%Since disease usually mild and avoidable not used much hereChemotherapyNucleic Acid SynthesisPolymerases are often virally encodedOther enzymes in nucleic acid synthesise.g.THYMIDINE KINASE in Herpes SimplexThymidine KinaseViral or cellular thymidine kinase adds first phosphatePO4PO4PO4Cellular kinases add two more phosphates to form TTPChemotherapyWhy does Herpes simplex code for its own thymidine kinase?TK-virus cannot grow in neural cells because they are not proliferating(not making DNA)Although purine/pyrimidines are present,levels of phosphorylated nucleosides are lowAllows virus to grow in cells that are not making DNA“Thymidine kinase”is a misnomerDeoxynucleoside kinaseNON-SPECIFICChemotherapyNeed for activation restricts drug to:Viruses such as HSV that code for own thymidine kinase Virus such as cytomegalovirus and Epstein-Barr virus that induce cells to overproduce their own thymidine kinase In either case it is the VIRUS-INFECTED cell that activates the drugChemotherapyNucleotide analogsSugar modificationsBase modificationsSelectivity Viral thymidine kinase better activator Cellular enzyme may not be present in non-proliferating cells Activated drug is more active against viral DNA polymerase that against cell polymeraseChemotherapyGuanine analogsAcyclovir=acycloguanosine=ZoviraxGanciclovir =Cytovene Activated by viral TK Activated ACV is better(10 x)inhibitor of viral DNA polymerase than cell DNA polymeraseExcellent anti-herpes drugChemotherapyACV acts in two ways:Competes with GTP Chain terminator Good anti-herpes drugTPPGPCPANormal DNA synthesisTPPGPCPAPAACGP-P-PTerminationACV acts in two ways:Competes with GTP Chain terminatorSelective:Virus phosphorylates drug Polymerase more sensitiveChemotherapyAdenine arabinoside (Ara-A)Problems:Severe side effects Resistant mutants(altered polymerase)Chromosome breaks(mutagenic)Tumorigenic in rats Teratogenic in rabbits InsolubleUse:topical applications in ocular herpes simplexChemotherapyAdenine arabinoside HSV encephalitis Neonatal herpes Disseminated herpes zoster Hepatitis BPoor in vivo efficacy:DEAMINATIONChemotherapyOther sugar modifications:AZTazidothymidineDDIdideoxyinosineDDCdideoxycytidineProdrugs：FamciclovirTaken orallyConverted byPatients metabolismHSV thymidine kinasePHost kinasePPAvailable as topical creamSmithKlein-BeechamChemotherapyRibavirin（病毒唑）Guanosine analog Non-competitive inhibitor of RNA polymerase in vitro Little effect on flu in vitro Often good in animals but poor in humans Aerosol use:respiratory syncytial virusChemotherapyMay inhibit RNA cap formationNNNHNH2NOCH3OCH2P PCH2OCH3PbaseMay induce mutations in RNA virusesChemotherapyViral Protein synthesis:No inhibitorsBindingFusionReverse transcriptionNuclear localizationUncoatingIntegrationTranscriptionSplicingRNA exportGenomic RNAmRNATranslationModificationBuddingAssemblyMaturationEndocytosisLysosomeChemotherapyProtein processing:Proteolysis Glycosylation ChemotherapyGAGIntegrase Polymerase ProteaseGAG/POL polyproteinChemotherapyGAGIntegrase PolymeraseProtease folds and cuts itself freeChemotherapyGAGIntegrase PolymeraseProtease cuts at a site between the integrase and polymeraseChemotherapyGAGIntegrasepolymeraseChemotherapySaquinavirChemotherapySaquinavir:In HAART Viremia CD4+cells Ritonavir:In HAART AIDS deaths 58%IndinavirNelfinavirHIV aspartyl protease inhibitorsChemotherapyIndinavir(Merke)INDINAVIR+AZT+3TCNo detectable HIV by PCR20,000-11,000,000 RNA copies/ml 1 year No replication No resistanceChemotherapyInfluenzaRequires neuraminidase to escape from cellRequires neuraminidase to penetrate mucusZanamivir-RELENZA(fall 1997)Neuraminidase inhibitorActive against Influenza A and Influenza BChemotherapyAfter neuraminidase inhibition,flu hemagglutinin binds to sialic acid on other virus particles:virus clumpsOR virus sticks to mucous in respiratory tractVirus hemagglutinin sticks new virus particle to sialic acid on cell surfaceVirus cannot escape from infected cellNeuraminidase of virus removes sialic acid from cell surface thereby releasing virusChemotherapyZanamivir-RelenzaNeuraminidase inhibitorNasal sprayShortens symptoms by a few daysTamiflu:Oral neuraminidase inhibitor抗病毒化学制剂n n理论上病毒复制的任何环节都是抗病毒药物发挥作用的靶位置，但要区别病毒复制与宿主细胞正常生理过程是很困难的。因此大多数抗病毒药物的应用都有限制，甚至对机体有毒性作用n n抗病毒药的机制多是在药物进入宿主细胞后受病毒的某种酶的作用形成具有抗病毒活性的新的成份抗病毒化学制剂的种类n n核苷（酸）类似物n nDNA聚合酶（包括逆转录酸）抑制剂n n蛋白酶抑制剂n n免疫调节剂（干扰素）核苷类似物n n无环鸟苷（Acyclovir，ACV）n n是鸟嘌呤或脱氧鸟嘌呤核苷类似物，受病毒编码的胸腺嘧啶核苷激酶（Thymine Kinase，TKase）的作用而磷酸化，对病毒编码的DNA聚合酶比对宿主细胞的DNA聚合酶有更强的抑制作用n n主要用于疱疹病毒感染n n阿糖胞苷（Adenine arabinoside,Ara-A）uu在细胞内被磷酸化形成Ara-ATP，后者与dTMP竞争抑制DNA的合成，对DNA聚合酶也有作用uu用于疱疹病毒、HBV感染DNA聚合酶抑制剂n n叠氮胸苷（Azidothymidine，AZT）uu对逆转录活性的抑制比对细胞DNA聚合酶敏感100倍以上，故通过阻断前病毒的合成而抑制逆转录病毒的复制uu用于HIV感染的治疗，但HIV能产生耐药性（基因突变所致）蛋白酶抑制剂n n赛科纳瓦（赛科纳瓦（SaquinavirSaquinavir）uuHIVHIV的的晚期蛋白酶将病毒子代大分子蛋白裂晚期蛋白酶将病毒子代大分子蛋白裂解为解为病毒结构蛋白（形成成熟病毒体核心成病毒结构蛋白（形成成熟病毒体核心成份）和病毒逆转录酶分子。份）和病毒逆转录酶分子。SaquinavirSaquinavir抑制抑制晚期蛋白酶的活性，因此不成获得成熟病毒晚期蛋白酶的活性，因此不成获得成熟病毒认壳蛋白和逆转录酶，但对宿主细胞蛋白酶认壳蛋白和逆转录酶，但对宿主细胞蛋白酶没影响没影响uu与逆转录酶抑制剂联合使用可以减低血液与逆转录酶抑制剂联合使用可以减低血液中中HIVHIV的含量，延长存活期，但对细胞内的的含量，延长存活期，但对细胞内的HIVHIV作用差作用差抑制病毒脱壳和装配n n金刚烷胺：抑制病毒脱壳n n用于流感治疗Antiviral agents in clinical useAcyclovirAcyclovirNucleoside analogueNucleoside analogueHSVHSVAmantadineAmantadine Uncoating and assemblyUncoating and assembly Influenza AInfluenza ADideoxy-Dideoxy-nucleosidenucleosideNucleoside analogueNucleoside analogueHIVHIVFoscametFoscametInhibition of polymeraseInhibition of polymeraseCMV retinitisCMV retinitisGanciclovirGanciclovirNucleoside analogueNucleoside analogueCMVCMVIdoxuridineIdoxuridineNucleoside analogueNucleoside analogueHSV topicalHSV topicalInterferon-alfaInterferon-alfa ImmunomodulatorImmunomodulatorHBV&HCVHBV&HCVPenciclovirPenciclovirNucleoside analogueNucleoside analogueHSVHSVRitonavirRitonavirProtease inhibitorProtease inhibitorHIVHIVSaquinavirSaquinavirProtease inhibitorProtease inhibitorHIVHIVTribavirinTribavirinNucleoside analogueNucleoside analogueRSVRSVZidovudineZidovudineNucleoside analogueNucleoside analogueHIVHIVAction site of antiviral agentsReplication Replication stagestagePotential antivial Potential antivial targettargetExampleExampleAttachmentAttachmentBlock virion Block virion attachmentattachmentDown-regulation of Down-regulation of cellular receptorcellular receptorAntibody to viral Antibody to viral binding sitebinding siteAntibody to cell Antibody to cell receptorreceptorPenetration Penetration UncoatingUncoatingStablize viral capsid Stablize viral capsid in endosomein endosomeInhibit uncoatingInhibit uncoatingAmantadineAmantadineDisoxaril,aridoneDisoxaril,aridoneViral Nucleic Viral Nucleic acid synthesisacid synthesisRNA&DNA RNA&DNA polymerase inhibitorspolymerase inhibitors&chain terminators&chain terminatorsNucleoside analogues Nucleoside analogues(acyclovir,vidarabine)(acyclovir,vidarabine)foscametfoscametReplication Replication stagestagePotential antivial Potential antivial targettargetExampleExampleTranscription&Transcription&RNA genomeRNA genomeAnti-sense Oligo-Anti-sense Oligo-Anti-gene Oligo-Anti-gene Oligo-Decoy RNA Decoy RNA RibozymeRibozymeDecoy RNA means Decoy RNA means RNA that is RNA that is corresponding to corresponding to regulatory region)regulatory region)Translation&Translation&protein protein preocessingpreocessingCapping inhibitor Capping inhibitor Translation inhibitorTranslation inhibitor Inhibitors of Inhibitors of glycosylation glycosylation Proteolytic cleavage Proteolytic cleavage inhibitorsinhibitors Interferons Interferons CastanospermineCastanospermine Saquinavir,ritonavirSaquinavir,ritonavirVirion Virion AssemblyAssemblyNucleocapsid Nucleocapsid assemblyassemblyBuddingBuddingTransdominant Transdominant mutant proteinmutant proteinAmamtadineAmamtadine干扰素和干扰素诱生剂的应用n nIFNn nIFN诱生剂uuPoly I:CPoly I:Cuu甘草甜素甘草甜素uu芸芝多糖芸芝多糖中草药n n黄芪n n板蓝根