病毒学双语版课件Chapter6-2共39页
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病毒学VirologyPPT课件
（二）病毒纯化的方法
1,病毒纯化方法的依据
(1)病毒颗粒具有一定的大小和密度，在离 心 场中能以一定的沉降速率沉降
(2)病毒颗粒的主要化学组成为蛋白质
2.病毒纯化的方法 包括:超速离心,沉淀法,凝集技术,液态两
相分配系统,有机溶剂萃取,层析和电泳等
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三、病毒的测定（assay of vrvuses）
病毒感染细胞培养引起的细胞显微表现的改 变，如细胞聚集成团，肿大、园缩、脱落、 细胞融合形成多核细胞、细胞内出现包涵体 （inclusion body），乃至细胞裂解等
（３）植物病毒－坏死斑或称枯斑 （necrosis spot）
植物病毒感染敏感植物叶片所形成的局部 病损区域．
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（四）盲传（blind passage）
噬菌体（bacteriophage） 噬蓝绿藻体（cyanophage） 支原体噬菌体（mycohasmemaphage）
植物病毒 （Plant Viruses）
植物病毒（plant viruses） 噬藻体(phycophage)
真菌噬菌体或真菌病毒(mycophage)
动物病毒 （Animal Viruses）
（三）病毒存在的认定 1、系统症状
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2、局部反应
(1)噬菌体—噬菌斑(plaque) 噬菌体感染生长在营养琼脂平板上的细菌所形 成的，具有一定大小和形状的透明区域。
(2)动物病毒—蚀斑或称空斑(plaque) 动物病毒感染单层细胞培养所形成的局部病损 区域，系由病毒的致细胞病变作用所引起．
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致细胞病变作用（Cytopathic effect ， CPE） ：
原生动物病毒(protozoal viruses) 无脊椎动物病毒(inverteble viruses)
病毒学双语版课件(1)ppt课件
© Academic Press, 2000. Slide 3/43
Chapter 7: Pathogenesis
Virus Pathogenesis
• Virus pathogenesis is an abnormal & fairly rare situation the majority of virus infections are silent & do not result in outward signs of disease. • It is sometimes said that viruses would disappear if they killed their hosts - this is not necessarily true. • It is possible to imagine viruses with a hit-and-run strategy, moving quickly from one dying host to the next & relying on continuing circulation for their survival. • Nevertheless, there is a clear tendency for viruses not to injure their hosts if possible. • Ideally, a virus would not even provoke an immune response from its host, or at least be able to hide to avoid the effects. • Three major aspects of virus pathogenesis must be considered: direct cell damage resulting from virus replication, damage resulting from immune activation or suppression, & cell transformation caused by viruses.
Chapter 7: Pathogenesis
Virus Pathogenesis
• Virus pathogenesis is an abnormal & fairly rare situation the majority of virus infections are silent & do not result in outward signs of disease. • It is sometimes said that viruses would disappear if they killed their hosts - this is not necessarily true. • It is possible to imagine viruses with a hit-and-run strategy, moving quickly from one dying host to the next & relying on continuing circulation for their survival. • Nevertheless, there is a clear tendency for viruses not to injure their hosts if possible. • Ideally, a virus would not even provoke an immune response from its host, or at least be able to hide to avoid the effects. • Three major aspects of virus pathogenesis must be considered: direct cell damage resulting from virus replication, damage resulting from immune activation or suppression, & cell transformation caused by viruses.
医科大学专业课程《病毒学》全册课件-教授主讲优质课件
《病毒学》简介
virus
医学病毒学是病毒学的一个重要分支， 主要是从医学的角度来研究病毒特性， 有时又叫医学分子病毒学。医学病毒 学研究范围包括病毒本质，传播模式 及致病机制，以及应用层面的药物及 疫苗研究。它和分子生物学及药物学 关系密切。
第一章
病毒学概论
virus
是一类非细胞型微生物 主要特点 体积非常微小，需在电子显微镜观察 结构简单，无细胞结构，只含一种类型核 酸（DNA或RNA）和蛋白质 严格的细胞内寄生，只能在活细胞中增殖 对抗生素不敏感，但对干扰素敏感
真菌 真核细胞 +
DNA＋RNA
非细胞 DNA或RNA
复制 -
+ 二分裂 +
+
有性或无性
增殖方式 抗生素
+
干扰素
+
-
-
一、病毒的形态、结构与分类
virus
病毒的大小：以 纳米（nm）为计量 单位, 一般 30~200nm
The largest : （ 300nm, 痘病毒） The smallest: 10 nm 如口蹄疫病毒
与人类关系
virus
引起传染病：75%以上 可能是人类某些肿瘤的病因之一 鼻咽癌 EBV 宫颈癌 人乳头瘤病毒、单纯疱疹病毒Ⅱ型 原发性肝癌 乙型肝炎病毒 传染性强，流行广泛，很少有特效药
virus
特性 滤菌器 结 构 细胞壁 核酸类型
无细胞培养
病毒
+
细菌 原核细胞 +
DNA＋RNA
衣 壳
virus
核衣壳
二）衣壳
成分——包裹在核酸外的 蛋白质，组成壳微粒 作用： 保护病毒核酸； 与易感C上V受体结合， 辅助V对易感C的感染； 抗原性，诱导机体免疫 应答。
病毒学教学课件
General structure of a virion
衣壳组成------壳粒capsomeres
数目
壳粒
排列
螺旋对称型 helical symmetry 二十面体对称型 icosahedral symmetry 复合对称型 complex symmetry
螺旋对称型与二十面体对称型
Fig (A) icosahedral symmetry ; (B) helical symmetry.
临床病毒学现状
发病率高； 传染性强、流行广； 人类部分肿瘤与病毒感染有关； 某些病毒感染有致畸作用； 有效药物少。
病毒的概念
病毒（Virus）： 是一类形态最微小，结构最简单，
仅含一种类型核酸，必须在活细胞内才 能显示生命活性的非细胞型微生物 （acellular microorganism）。
病毒的基本性状
第一节 病毒的大小与形态
病毒体（Virion）
• 定义：一个完整成熟的病毒颗粒 • 特点：完整性+感染性
病毒的大小（以nm作为测量单位）
最大：痘病毒（300 nm） 最小：细小DNA病毒（20 nm）
准确测量方法：
电镜( Electron microscope, EM )
Fig EM of Influenza virus. Scale bar =100nm
病毒核酸功能
主导病毒感染、增殖、遗传和变异的物质基础。
• 指导病毒复制 • 遗传物质，又称基因组，决定病毒的特性 • 感染性核酸
病毒蛋白质的分类
结构蛋白structure protein 衣壳蛋白、基质蛋白和包膜糖蛋白
非结构蛋白non-structure protein 调节蛋白、酶类
医学病毒学PPT课件
02 保持社交距离 避免近距离接触有症状的人，尽量保持至少1米的安全 距离。
03
佩戴口罩
在公共场所、尤其是室内环境佩戴医用口罩或N95口 罩，以阻挡含有病毒的飞沫进入呼吸道。
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增强免疫力
保持充足的睡眠、均衡的饮食、适当的锻炼，以提高 身体免疫力，抵抗病毒侵袭。
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接种疫苗
根据当地卫生部门的建议，及时接种相关疫苗，以降 低感染风险。
播的风险。
疫苗研发与使用
疫苗研发
通过科研机构和制药公司的合 作，加速针对新型病毒的疫苗
研发进程。
临床试验
确保疫苗在投入使用前经过严 格的临床试验，确保安全性和 有效性。
分阶段使用
疫苗上市后，根据疫情情况和 接种计划，分阶段、分人群进 行接种。
监测与评估
在疫苗使用过程中，持续监测 其安全性和有效性，并根据实
药物设计与筛选
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基于病毒结构信息，设计和筛选能够抑制病毒复制或破坏病毒
颗粒的药物分子。
THANK YOU
感谢聆听
病毒基因组每天约产生 10^-5~10^-8个突变， 其中大部分为负突变（降 低生存能力的突变）。
病毒进化的规律与趋势
适应性进化
病毒在传播过程中逐渐适应宿主环境 的过程，表现为毒力增强或减弱。
协同进化
病毒与宿主之间相互影响、共同进化 的过程，如病毒抗原变异与宿主免疫 应答之间的协同进化。
定向进化
在选择压力下，病毒基因组朝着特定 方向进化的过程，如抗药性病毒的出 现。
血液传播
病毒通过血液、体液等途径传播，如丙肝病毒、 乙肝病毒等。
接触传播
病毒通过接触口、鼻、眼等黏膜或破损皮肤进入 人体，如HIV病毒、HBV病毒等。
病毒学双语版课件ppt课件
• Cell-transforming viruses may have RNA or DNA genomes,
but all have at least a DNA stage in their replication cycle, i.e.
the only RNA viruses directly capable of cell transformation
2019/8/30
2 Slide 2/47
Chapter 7: Pathogenesis
Cell Transformation by Viruses
Transformed cells have an altered phenotype, which is displayed as one (or more) of the following characteristics:
• Transformation may or may not result in cells able to produce tumours in experimental animals, which is properly known as neoplastic transformation.
• In contrast, the oncogenes of cell-transforming DNA viruses are unique to the virus genome - there are no homologous sequences present in normal cells.
Chapter 7: Pathogenesis
Pathogenesis
<< Part 1 (click on this link)
病毒学双语版课件Chapter6-2
Chapter 6: Infection
Infection: Part 2
<< Part 1
© Academic Press, 2000.
Slide 1/38
Chapter 6: Infection
Evasion of Immune Responses by Viruses
Inhibition of MHC I-Restricted Antigen Presentation:
© Academic Press, 2000.
Slide 6/38
Chapter 6: Infection
Evasion of Immune Responses by Viruses
Evasion of the Complement Cascade:
• Poxviruses, herpesviruses & retrovirus families encode mimics of normal regulators of complement activation proteins, e.g. secreted proteins which block C3 convertase assembly & accelerate its decay.
• CTLs can only respond to foreign antigens presented by MHC I complexes on the target cell.
• A number of viruses interfere with MHC I expression or function to disrupt this process & evade the CTL response.
Infection: Part 2
<< Part 1
© Academic Press, 2000.
Slide 1/38
Chapter 6: Infection
Evasion of Immune Responses by Viruses
Inhibition of MHC I-Restricted Antigen Presentation:
© Academic Press, 2000.
Slide 6/38
Chapter 6: Infection
Evasion of Immune Responses by Viruses
Evasion of the Complement Cascade:
• Poxviruses, herpesviruses & retrovirus families encode mimics of normal regulators of complement activation proteins, e.g. secreted proteins which block C3 convertase assembly & accelerate its decay.
• CTLs can only respond to foreign antigens presented by MHC I complexes on the target cell.
• A number of viruses interfere with MHC I expression or function to disrupt this process & evade the CTL response.
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© Academic Press, 2000.
Slide 2/38
Chapter 6: Infection
Evasion of Immune Responses by Viruses
ቤተ መጻሕፍቲ ባይዱ
Inhibition of Cytokine Action:
• Cytokines are secreted polypeptides that co-ordinate important aspects of the immune response, including inflammation, cellular activation, proliferation, differentiation, & chemotaxis.
Chapter 6: Infection
Evasion of Immune Responses by Viruses
Inhibition of MHC I-Restricted Antigen Presentation:
• CTLs can only respond to foreign antigens presented by MHC I complexes on the target cell.
• Similar proteins are made by other viruses such as HHV-5 (CMV), & herpesviruses in general appear to have a number of sophisticated mechanisms to avoid NK cell killing.
© Academic Press, 2000.
Slide 3/38
Chapter 6: Infection
Evasion of Immune Responses by Viruses
Interference with Apoptosis
Virus Resistance to Interferons:
• Epstein-Barr virus EBER RNAs are similar in structure & function to the adenovirus VA RNAs.
• The EBNA-2 protein also blocks interferon-induced signal transduction
• The poxvirus Molluscum contagiosum encodes a homologue of MHC I which is expressed on the surface of infected cells but is unable to bind an antigenic peptide, thus avoiding killing by NK cells which would be triggered by the absence of MHC I on the cell surface.
• Some viruses are able to inhibit the expression of certain chemokines directly.
• Herpesviruses & poxviruses encode "viroceptors" - virus homologs of host cytokine receptors which compete with cellular receptors for cytokine binding but fail to give transmembrane signals.
• High-affinity binding molecules may also neutralize cytokines directly, & molecules known as "virokines" block cytokine receptors again without activating the intracellular signalling cascade.
© Academic Press, 2000.
Slide 1/38
Chapter 6: Infection
Evasion of Immune Responses by Viruses
Inhibition of MHC II Restricted-Antigen Presentation:
• MHC-II antigens are essential in the adaptive immune response in order to stimulate the development of antigenresponsive clones of effector cells.
• Vaccinia virus is known to show resistance to the antiviral effects of interferons.
• Herpesviruses & papillomaviruses interfere with the processing & surface expression of MHC II-antigen complexes, inhibiting the CTL response.
Inhibition of Natural Killer Cell Lysis:
• A number of viruses interfere with MHC I expression or function to disrupt this process & evade the CTL response.
• Such mechanisms include downregulation of MHC I expression by adenoviruses & interference with the antigen processing required to form an MHC I-antigen complex by herpesviruses.