Herpes virus Flashcards Preview

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Flashcards in Herpes virus Deck (25)
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1
Q

How long does the Herpes infection last?

A

All your life

2
Q

Why do Herpes viruses not have the capacity to mutate?

A

DNA-based genome

Proof-reading error correcting is better than in RNA

3
Q

How many species can Herpes infect?

A

Every species known to man

4
Q

How many Herpes strains infect humans?

A

8

5
Q

What strain is known to cause cold sore?

A

HS1

6
Q

What strain is known to cause genital sore?

A

HS2

7
Q

What strain is known to cause chickenpox?

A

Varicella Zoster

8
Q

Why is the Herpes virus lifelong?

A

Due to its latency

9
Q

What is latency?

A

Latency is the maintenance of the viral genome in the absence of the full viral gene expression

Some genes are expressed but do not produce viral proteins

10
Q

What are the inactive and active stages called?

A

Latent

Lytic

11
Q

Why is the active stage called lytic?

A

Because activation causes cell lysis

12
Q

Why is it not optimal that Herpes viruses are latent

A

They need to transmit

13
Q

Why do Herpes viruses stay latent?

A

The viral population has to grow in number in order to combat the host immune system

Encode a repertoire of immune evasion factors

14
Q

What is the pathogenesis of the primary infection?

A

At site of inoculation the virus causes a lesion

This is controlled and removed by the immune system

Virus travels along the sensory neurons that innervate the site of innoculation

Reaches the cell body and this is were latency is established

Silent - no immune response is triggered

Retrograde spread happens

15
Q

What is retrograde expasion?

A

The viral particles move from the dendrites to the cell body to establish latency

This is opposite to the flow of information through a neuron

16
Q

How does recurrent infection occur?

A

No known stimulus

Gene expression initiates and transcription kicks off

New viruses are produced in the cell body of the neuron

Assembly forms in vesicles at distal end of a neuron and contacts cells from the initial site of inoculation

Cells replicate at distal end and cell death and lesion occurs

Anterograde expansion

17
Q

Who is at risk for Herpes reactivation?

A

Immunocompromised patients

18
Q

What is shingles?

A

Reactivation of varicella zoster virus in later life

19
Q

How does shingles present?

A

As localised rashes where the nerves containing latent virus innervates

Circumscription

20
Q

What is the Fc region

A

The opposite end of the antigen-binding domains of the antibody

Communicates with

Complement system
Macrophages
Natural Killer Cells

21
Q

How does the Herpes virus mantain latency?

A

Evades antibodies

Evades immune system

22
Q

How does Herpes Virus evade antibodies?

A

Making their binding irrelevant

Encode glycoproteins that prevent the antibody from contacting the immune defeces mediated by the Fc region

Antibody can no longer

Fix complement
Recruit macrophages

23
Q

How does Herpes Virus evade immune system?

A

Normally, the antigens are chopped up into peptides in the proteasome and transmitted to the ER via TAP transporter proteins until MHC I presents them on their surface

Herpes stops this from working by making a protein called IPC47 that binds to TAP

24
Q

What is IPC47?

A

Protein made by Herpes virus that blocks the action of TAP from transporting peptides from proteasome to the ER

25
Q

What does the Fc region do?

A

Recruits macrophages
FIxes complement
Recruits NK cells