病毒的遗传与变异.ppt

Conceptions Genetics遗传 Aftervirusreplicates thecharactersontheprogenyvirusaresimilarwiththepreviousgeneration Variation变异 Aftervirusreplicates thecharactersontheprogenyvirusaredifferentwiththepreviousgeneration 一 Variationmechanism病毒变异的机制 Heritablevariation遗传型变异因病毒遗传物质核酸发生了改变 导致其变异后的性状可遗传给子代病毒 Non Heritablevariation非遗传型变异又称基因产物的相互作用 因病毒核酸并未发生改变 所以此变异一般不能遗传 一 Heritablevariation遗传型变异 Virulencechanges Conditionallethalmutant条件致死突变株eg temperaturesensitive ts mutant Host rangemutant hr 宿主范围突变株Drug resistantmutant耐药突变株 1 GeneMutation基因突变 Recombination两个病毒基因组间核酸序列交换 组合Reassortment segmentedgenomes RNAviruses influenzavirus分节段的RNA病毒基因组之间 通过基因片段交换使子代基因组发生突变病毒基因组与细胞基因组之间的重组 2 Recombination Reassortment重组与重配 3 integration整合 二 Non Heritablevariation非遗传型变异 Interactions whentwogeneticallydistinctvirusesinfectacell 4differentphenomenacanensue继发 1 Phenotypicmixingortranscapsidation表型混合与核壳转移 2 genotypemixing基因型混合 3 enhancement增强 4 complementation互补 1 Phenotypicmixing表型混合 ThegenomeofvirusAcanbecoatedwiththesurfaceproteinofvirustypeB两株病毒共同感染同一细胞时 一种病毒复制的核酸被另一病毒所编码的蛋白质衣壳或包膜包裹 不是遗传物质的交换 而是基因产物的交换transcapsidation核壳转移 无包膜病毒发生的表型混合 2 genotypemixing基因型混合 GenomeA genomeB samecapsid衣壳CapsidA capsidB sameenvelope包膜实质 核酸未重组合 没有遗传性 3 enhancement增强两病毒混合培养 一病毒能增强另一病毒的产量 4 complementation互补 ClassificationofViruses病毒的分类 国际病毒分类委员会ICTV By2001 66families科 9subfamilies亚科 244genera属Forhumansandanimals 24families DNA 7 RNA 17forhumans basisofclassification病毒分类依据 Virionstructureandproteries病毒结构与性质Virionmorphologyandsize病毒大小和形态Symmetryofnucleocapsids核衣壳对称性Envelope有无包膜Physicochemicalproperties理化特性Antigenicproperties抗原性Biologicproperties生物学特性 Viroids 类病毒 Viroidsaresmall 250 400nt Nucleotide RNAmoleculeswitharod likesecondarystructure whichpossessnocapsidorenvelope whichareassociatedwithcertainplantdiseases 很小 250 400nt 杆状RNA分子 有二级结构无衣壳或包膜在核内增殖 严格细胞内寄生多与植物疾病相关 satellites卫星病毒 Virosid拟病毒 特点 1是RNA病毒 500 2000bp2复制需要辅助病毒3与辅助病毒基因无同源性4所致疾病与辅助病毒无关有两类 一类可编码自身衣壳蛋白另一类为卫星病毒RNA分子 Prions朊粒 consistofasingletypeofproteinmoleculewithnonucleicacidcomponent TheseagentsareassociatedwithdiseasessuchasCreutzfeldt Jakobdisease克雅病 亚急性海绵状脑病 inhumans scrapie痒病insheep bovinespongiformencephalopathy BSE 牛海绵状脑病incattle Chapter19 ViralInfectionandImmunity 病毒的感染与免疫 Thischapterwillfocuson ConceptionsHorizontalandVerticaltransmission水平传播及垂直传播 inapparentandapparentinfection隐性感染及显性感染 Persistentviralinfection持续性病毒感染 Latentinfection潜伏性感染 Chronicinfection慢性感染 Slowvirusinfection慢发病毒感染 Inclusionbody包涵体QuestionsDescribethetypesandroutesofviralinfection Whatisinterferon干扰素 Listthebioactivitiesofit Section1ViralInfection病毒的感染 Viralinfection theprocessofvirusenteringandmultiplyinginthehumanoranimalbody 病毒侵入人及动物机体并在其中增殖的过程Viralpathogenesis theinteractionbetweenviral hostfactorsthatleadstodisease a Aparticulardiseasemaybecausedbyseveralvirusesthathaveacommontissuetropism取向 preference选择 e g HAV HBV HCV HDV HEV etc hepatitis b Aparticularvirusmaycauseseveraldifferentdiseasesornoobservable引人注意的symptoms e g HSV单纯疱疹病毒 1 pharyngitis咽炎 herpeslabialis唇疱疹 genitalherpes生殖道疱疹 encephalitis脑炎 keratoconjunctivitis角膜结膜炎 Thecharacteristicofviralinfection Respiratorytract痰 唾液 飞沫 气溶胶Alimentarytract饮水 食物Skin动物咬伤 昆虫叮咬Blood输血 注射 针刺 器官移植Genitaltract性交Urinarytract洗浴placenta birthcanal孕期 分娩 I tractofviralinfection感染途径 II Modesofviraltransmission传播方式 Horizontaltransmission水平传播 directhost to hosttransmissionofviruses 人与人不同个体间的传播 Verticaltransmission垂直传播 thetransmissionofvirusesfromparenttotheyoungviaplacenta birthcanal 亲代通过胎盘或产道传给子代 Localinfection SystemicinfectionDirectcontact 细胞 细胞blood 侵入部位 血液neuralsystem 感染部位神经元 III Routesoftransmission播散方式 Unapparentinfection隐性感染 subclinicalinfection Virusmultiplyinthehostcellswithoutcausingclinicalsymptomsorcausingmildsymptoms Significance importantsourceofinfection 重要传染源acquireimmunity 获得免疫力misdiagnoseorfailtodiagnose 易误诊和漏诊 IV Typesofinfection感染类型 Virusesmultiplyinhostcellsandcauseclinicalsymptoms Acuteinfection急性病毒感染 shortincubation suddenonset andshortdurationofdisease severaldaystoweeks e g commoncold influenza hepatitisA Persistentviralinfection持续性病毒感染 virusespersistinthehostforlongtimeperiod severalmonthsoryearsordecades sometimesforthewholelife Apparentinfection显性感染 Latentinfection Virusespersistinthehostinahidingformandthereisnoproductionofinfectiousviruses Undersomeconditions thelatentvirusesareactivatedandmultiplytoproduceclinicalsymptoms E g HSV 1Chronicinfection Afteracuteinfection virusesarenoteliminatedandthereisintermittent间歇的multiplicationandshedding排出ofviruses Viruscanbecontinuouslydetected oftenmild ornoclinicalsymptoms E g HBVcausechronichepatitisB Slowvirusinfection delayinfection possessaprolongedincubationperiodlastingmonthsoryearsafterviralinfection duringwhichnoclinicalsymptomsappearbuttheinfectiousvirusesmaymultiply thenchronicandprogressivediseasesappearandeventuallydevelopintofatalinfections E g Measlesvirus SSPE acuteinfectionwithrarelatecomplication Persistentinfection includes herpeslabialis唇疱疹byreactivatedHSV HSV 1establisheslatentinfectionandcanrecur重现fromthetrigeminalganglia 三叉神经节 A Directvirus hostcellinteraction对宿主细胞直接作用Cytocidalinfection溶细胞型感染Steadystateinfection稳定状态感染Cellapoptosis细胞凋亡e g HSVViralgenesintegrateintocellularchromosome整合e g EBV HIV Cellhyperplasia增生andcelltransformation转化Inclusionbody形成包涵体B Virus inducedimmunopathology免疫病理作用HumoralimmuneeffectCellimmuneeffectVirusesdestroyimmunesysteme g HIVdestroyCD4 TCSelf immunedisease V Mechanismsforviralinfection 病毒感染机制 1 Cytocidalinfection溶细胞型感染viralreplicationcausecelldeath nakedvirusinfection e g poliovirus脊髓灰质炎病毒 adenovirus Mechanism blocksynthesisofcellularmacromolecules produceandaccumulatetoxicviralproteins destroyorganelles e g lysosomepermeability 溶酶体膜通透性 cellautolyze细胞自溶 A Directinteractionbetweenvirusesandhost Hostcelllysis 2 Steadystateinfection稳定状态感染envelopedvirusesinfection littledestructionofcells Alterationofhostcellmembrane 3 Apoptosis细胞凋亡cellprogrammeddeath4 Integrationinfection整合Integration ViralDNAintegratesintocellularchromosome Budding 5 Cellhyperplasia增生andcelltransformation转化 Cellhyperplasia增生 病毒不仅不抑制宿主细胞DNA合成反而促进celltransformation转化 病毒感染后使宿主细胞形态发生变化 6 Inclusionbody包涵体Theroundorovalstructuresinthecytoplasmornucleus orboth acidophilicorbasophilicwhichcanbeobservedinsomeinfectedcellsunderlightmicroscope Significance laboratorydiagnosis E g Negribodyforrabiesvirus Negribodyofrabiesvirusininfectedneuron H E stainedtissue intra cytoplasmic HumoralimmunopathologyNewAgs Ag Ab complementAg AbcomplexdepositCell mediatedimmunopathologyNewAgsinducecytotoxiceffect Virus inducedimmunosuppression e g HIV measlesvirus rubellavirus风疹病毒 autoimmuneresponse againsttoself cell B Virus inducedimmunopathology host encodedproteinswhichcaninhibitviralreplication Itcanbeproducedbymacrophages lymphocyte somaticcell Forhuman produ