Lab Dignosis and Host Rsponse to Viral Infection在线视频

The laboratory methods include culture,

rapid detection and serologic test.

Culture1
00:00:00,060 --> 00:00:09,980

The laboratory methods include culture,
实验室检查方法包括组织培养

rapid detection and serologic test.
快速检测和血清学检查

Culture
组织培养

The viruses can be cultivated in animals,
病毒培养可以采用动物、鸡胚

in fertile eggs, and in cell cultures.
和细胞培养

Specific types of tissue culture cells are used to grow viruses.
特定种类的组织培养细胞可以用来培养病毒

Rapid detection includes electron microscopy for the
快速检测包括电子显微镜观察

detection of viral particles,
检测病毒颗粒

detection of viral antigen by enzyme-linked
酶联免疫吸附测定法（ELISA）和免疫荧光法（IF）

immunosorbent assay (ELISA) and immunofluorescence (IF),
检测病毒抗原

and detection of viral nucleic acid by
和聚合酶链式反应（PCR）

polymerase chain reaction (PCR).
检测病毒核酸

Serologic test is to detect the immune responses
血清学检查用来检测

to the specific virus,
特异性的病毒免疫应答

such as specific IgG or IgM.
例如特异性IgG或者IgM

Serologic tests are used for the identification of viruses
血清学检查也用来鉴定

that are difficult to isolate and grow in cell culture,
难以在细胞培养中生长和分离的病毒

as well as viruses that cause diseases of long duration
和长病程的病毒感染

(e.g., EBV, HBV, and HIV)
（例如EBV, HBV, 和HIV）

The last question is how does our immune system fight the viruses?
最后一个问题是我们的免疫系统是怎样和病毒对抗的?

One is Interferon (IFN).
一方面是干扰素（IFN）

Nonspecific host defense mechanisms
非特异性免疫机制

are usually elicited very soon after viral infection.
通常在病毒感染之后很快就发挥作用

After the virus penetrates the natural barriers,
病毒穿过天然屏障，例如皮肤，后

such as skin, it activates the innate host defenses
会激活固有免疫防御

(e.g., fever, interferon, macrophages, dendritic cells, NK cells).
（例如：发烧、干扰素、巨噬细胞、树突状细胞、NK细胞）

The innate immune responses attempt to limit
固有免疫可以限制

and control local viral replication and spread.
和控制局部病毒增殖和传播

The most prominent among the innate immune responses
在固有免疫应答中最重要的效应就是

is the induction of interferons.
干扰素的生成

Interferons are host-coded proteins that are members of the large
干扰素是宿主编码的蛋白质，属于细胞因子

cytokine family and which inhibit viral replication.
能够抑制病毒的增殖

When a virus invade host cell 1,
当有一种病毒入侵宿主细胞1

the infected cell makes interferon.
这个被感染的细胞就会产生干扰素

Interferon induces changes that protect host cell 2.
干扰素可以诱导一些反应来保护宿主细胞2

Interferon stimulates cell to turn on genes for antiviral proteins production.
干扰素刺激细胞启动产生抗病毒蛋白基因的表达

The other one is natural killer cell.
另一方面是自然杀伤细胞（NK细胞）

NK cells are an early, antigen non-specific,
对于病毒，NK细胞是早期、非抗原特异性的

component of the immune response to viruses.
免疫应答的一部分

Let's see the diagram,
我们来看看这个图表

just after the exposure to the viruses,
在被病毒感染之后

the IFN can be produced.
细胞会产生IFN

Then the NK cells increase and kill the infected cells.
然后NK细胞增殖并且杀伤被感染的细胞

And then specific cytotoxic T lymphocytes (CTLs) kill the infected cells.
接着特异性的细胞毒性T淋巴细胞（CTLs）杀伤被感染的细胞

Innate responses prevent most viral infections from causing disease.
固有免疫应答能够阻止大部分病毒感染引起的疾病

Specific humoral and cell-mediated immunity to viruses.
特异性抗病毒体液免疫和细胞免疫

Virus-encoded proteins serve as targets for the immune response.
病毒编码的蛋白质可以作为免疫应答的靶点

You should note that
值得注意的是

1. Virus-infected cells could be lysed by CTL.
1. 被病毒感染的细胞可以被CTL溶解

2. Humoral immunity protects the host against reinfection
2. 体液免疫能够保护机体不受到同一种病毒的

by the same virus.
二次感染

3. Neutralizing antibody directed against surface proteins
3. 针对表面蛋白的中和抗体

blocks the initiation of viral infection.
可以阻断病毒感染的发生

4. Secretory IgA is important in protecting against infection
4. 分泌型IgA对于呼吸道或者消化道的

by viruses through the respiratory or gastrointestinal tracts.
抗病毒感染有很重要的作用

Serologic tests are used to measure the immune response.
血清学检查可以用来检测免疫应答

An elevated titer of specific IgM suggests a recent primary infection.
特异性IgM的效价升高，预示近期的原发性感染

Four fold increase of IgG titer between acute phase and
在急性期和恢复期之间

convalescent phase is of diagnostic value.
IgG效价四倍增加具有诊断价值

Key words of this part are vertical / horizontal transmission,
这一节的关键词包括垂直/水平传播

CPE, inclusion body,
细胞病变效应，包涵体

inapparent / acute / chronic / latent / slow infection,
隐性/急性/慢性/潜伏/慢发感染

and interferon.
干扰素

A quiz about interferon.
我们来做一个关于干扰素的测试

Interferons are an important part of the host defense against viral infections.
干扰素是机体对抗病毒感染很重要的一部分

What is interferon’s principle mode of action?
干扰素主要的作用模式是什么呢？

A.It protects the virus-infected cell
A.它保护被病毒感染的细胞

B.It is present in the serum of healthy individuals,
B.它存在于健康人的血清里面

providing a viral surveillance role
发挥监视病毒的作用

C.It coats viral particles and blocks their attachment to cells
C.它能包裹病毒颗粒并且阻断病毒吸附到细胞上

D.It induces synthesis of one or more cellular proteins
D. 它可以诱导一种或多种

that protect the cells from infection of viruses
细胞抗病毒感染的蛋白质的合成

Which one is your choice?
你的答案是什么？

Yes, D is correct.
没错，答案是D

Interferon can not protect the infected cells,
干扰素不可以保护被感染的细胞

but protect the neighbour cells.
但是它可以保护邻近的细胞

Summary of this chapter.
这一章的总结

We have discussed about the structure, replication,
我们已经讨论了病毒的结构、增殖

variation and classification of viruses,
变异和分类

the viral infection and host response,
病毒感染和宿主的应答

and laboratory diagnosis of viral infection.
病毒感染的实验室诊断

and laboratory diagnosis of viral infection.
Now could you answer all the questions?
那么现在你可以回答这里所有的问题吗？

Now could you answer all the questions?
那么现在你可以回答这里所有的问题吗？

1.What are viruses?
1.什么是病毒？

They are the smallest pathogens
他们是最小的病原体

and contain only DNA or RNA.
只有DNA或者RNA

The nucleic acid is encased in a capsid,
衣壳包裹着病毒的核酸

and maybe surrounded by an envelope.
病毒可能会有包膜

2. What is the structure of a virus?
2. 病毒的结构是什么？

Basic structure, core and capsid.
基本结构，核心和衣壳

Some have envelope and spikes.
有些病毒有包膜和刺突

3. How do viruses replicate?
3. 病毒是怎么增殖的？

Self-replicate, 6 steps.
自我复制，6个步骤

Attachment, penetration,
吸附、穿入

uncoating, biosynthesis, assembly, and release.
脱壳、生物合成、装配和释放

4. How do viruses change their antigenicity?
4. 病毒是怎么改变它们的抗原性的？

They do mutation, gene recombination and gene reassortement,
它们会发生突变、基因重组和基因重配

and phenotypic mixing.
还有表型混合

5. How to classify the viruses?
5. 怎么对病毒进行分类？

The viruses can be classified bases on biological properties,
根据生物学特性

and transmission route and so on.
和传播途径等等可以将病毒分类

6. How does viral infection manifest itself?
6. 病毒感染是怎么表现出来的？

Please remember the iceberg concept.
请记住“冰山概念”

7.How can viral diseases be transmitted？
7. 病毒是怎么传播的？

Vertical and horizontal transmissions.
垂直和水平传播

8. How do we confirm the diagnosis by lab test?
8. 我们怎么通过实验室检测确诊病毒感染？

Culture, rapid detection, and serologic test.
培养、快速检测、血清学检查

9. How does our immune system fight the viruses?
9. 我们的免疫系统是怎样和病毒对抗的？

Interferon, NK cells, and specific immune responses.
干扰素、NK细胞和特定的免疫应答

Hope you can answer all of them and enjoy the learning process.
希望你能够回答所有的问题并且享受学习的过程

All these information will come again
当我们学到具体的病毒的时候

when we learn about the different viruses.
就会用到这节课的知识

Thank you for your listening. See you next class.
谢谢大家，我们下节课见

The viruses can be cultivated in animals,

in fertile eggs, and in cell cultures.

Specific types of tissue culture cells are used to grow viruses.

Rapid detection includes electron microscopy for the

detection of viral particles,

detection of viral antigen by enzyme-linked

immunosorbent assay (ELISA) and immunofluorescence (IF),

and detection of viral nucleic acid by

polymerase chain reaction (PCR).

Serologic test is to detect the immune responses

to the specific virus,

such as specific IgG or IgM.

Serologic tests are used for the identification of viruses

that are difficult to isolate and grow in cell culture,

as well as viruses that cause diseases of long duration

(e.g., EBV, HBV, and HIV)

The last question is how does our immune system fight the viruses?

One is Interferon (IFN).

Nonspecific host defense mechanisms

are usually elicited very soon after viral infection.

After the virus penetrates the natural barriers,

such as skin, it activates the innate host defenses

(e.g., fever, interferon, macrophages, dendritic cells, NK cells).

The innate immune responses attempt to limit

and control local viral replication and spread.

The most prominent among the innate immune responses

is the induction of interferons.

Interferons are host-coded proteins that are members of the large

cytokine family and which inhibit viral replication.

When a virus invade host cell 1,

the infected cell makes interferon.

Interferon induces changes that protect host cell 2.

Interferon stimulates cell to turn on genes for antiviral proteins production.

The other one is natural killer cell.

NK cells are an early, antigen non-specific,

component of the immune response to viruses.

Let's see the diagram,

just after the exposure to the viruses,

the IFN can be produced.

Then the NK cells increase and kill the infected cells.

And then specific cytotoxic T lymphocytes (CTLs) kill the infected cells.

Innate responses prevent most viral infections from causing disease.

Specific humoral and cell-mediated immunity to viruses.

Virus-encoded proteins serve as targets for the immune response.

You should note that

1. Virus-infected cells could be lysed by CTL.

2. Humoral immunity protects the host against reinfection

by the same virus.

3. Neutralizing antibody directed against surface proteins

blocks the initiation of viral infection.

4. Secretory IgA is important in protecting against infection

by viruses through the respiratory or gastrointestinal tracts.

Serologic tests are used to measure the immune response.

An elevated titer of specific IgM suggests a recent primary infection.

Four fold increase of IgG titer between acute phase and

convalescent phase is of diagnostic value.

Key words of this part are vertical / horizontal transmission,

CPE, inclusion body,

inapparent / acute / chronic / latent / slow infection,

and interferon.

A quiz about interferon.

Interferons are an important part of the host defense against viral infections.

What is interferon’s principle mode of action?

A.It protects the virus-infected cell

B.It is present in the serum of healthy individuals,

providing a viral surveillance role

C.It coats viral particles and blocks their attachment to cells

D.It induces synthesis of one or more cellular proteins

that protect the cells from infection of viruses

Which one is your choice?

Yes, D is correct.

Interferon can not protect the infected cells,

but protect the neighbour cells.

Summary of this chapter.

We have discussed about the structure, replication,

variation and classification of viruses,

the viral infection and host response,

and laboratory diagnosis of viral infection.

and laboratory diagnosis of viral infection.
Now could you answer all the questions?

Now could you answer all the questions?

1. What are viruses?

They are the smallest pathogens

and contain only DNA or RNA.

The nucleic acid is encased in a capsid,

and maybe surrounded by an envelope.

2. What is the structure of a virus?

Basic structure, core and capsid.

Some have envelope and spikes.

3. How do viruses replicate?

Self-replicate, 6 steps.

Attachment, penetration,

uncoating, biosynthesis, assembly, and release.

4. How do viruses change their antigenicity?

They do mutation, gene recombination and gene reassortement,

and phenotypic mixing.

5. How to classify the viruses?

The viruses can be classified bases on biological properties,

and transmission route and so on.

6. How does viral infection manifest itself?

Please remember the iceberg concept.

7. How can viral diseases be transmitted?

Vertical and horizontal transmissions.

8. How do we confirm the diagnosis by lab test?

Culture, rapid detection, and serologic test.

9. How does our immune system fight the viruses?

Interferon, NK cells, and specific immune responses.

Hope you can answer all of them and enjoy the learning process.

All these information will come again

when we learn about the different viruses.

Thank you for your listening. See you next class.