Immune Response to Viruses

Question 1

What is the response time of adaptive immunity?

Answer 1

Slow (days)

Question 2

What is the specificity of the adaptive immune response?

Answer 2

Highly specific

Question 3

What is the memory of the adaptive immune response?

Answer 3

Has memory

Question 4

What is adaptive immunity essential in?

Answer 4

The fight against intracellular pathogens such as viruses

Question 5

What does adaptive immunity best deal with?

Answer 5

Most stages of microbial pathogenesis and can have some effect on early stages of replication (toxicity, invasiveness, tissue damage, disease)

Question 6

What happens first in antigen recognition?

Answer 6

Virus is phagocytosed and destroyed by an APC

Question 7

What is the result of the virus being phagocytosed and destroyed by an APC?

Answer 7

Viral peptides (from the capsid)

Question 8

What do viral peptides do?

Answer 8

Bind to the MHC-ll

Question 9

What do APC’s have?

Answer 9

MHC-l and MHC-ll

Question 10

What happens after the viral peptides bind to the MHC-ll?

Answer 10

APC/DC leaves the site and moves to the lymph nodes

Question 11

What happens before encounter with antigens?

Answer 11

Mature lymphocytes with receptors for many antigens develop

Question 12

What happens in clonal selection?

Answer 12

Viral peptide (antigen) presented on MHC is used like a key by the dendritic cell, hunting around until it finds the matching lock

Question 13

What happens after the key find the lock?

Answer 13

Expansion of T and B lymphocytes expressing the same antigen receptor

Question 14

What do T cells differentiate into?

Answer 14

Cytotoxic CD8 cells, helper CD4 cells and also memory cells

Question 15

What is happening in the mucosa?

Answer 15

As soon as a virus enters and starts replicating, MHC l takes part of its capsid and presents it to T cells which causes cell death

Question 16

What does MHC ll stimulate?

Answer 16

CD4 T cells

Question 17

What does MHC I stimulate?

Answer 17

CD8 T cells

Question 18

Where are cytokines produced?

Answer 18

By CD4 T cells

Question 19

What do cytokines help?

Answer 19

CD8 T cells become activated

Question 20

What do cytotoxic T cells synthesise?

Answer 20

Special proteins that specifically kill the virally infected host cell

Question 21

What are cytotoxic T cells full of?

Answer 21

Granules (perforin and granzyme) which cause apoptosis when released

Question 22

What does the infected host cell do?

Answer 22

Lets the cytotoxic T cell know it is infected by presenting the viral antigen on the cell surface using MHC-l

Question 23

What do B cells differentiate into?

Answer 23

Memory cells and effector (mature and plasma) cells

Question 24

What must happen for the plasma cells to develop from B cells?

Answer 24

1. Unprocessed antigen needs to attach to the B cell receptor (BCR)
2. Helper T cell to attach to processed antigens presented by the APC MHC-ll (this causes the cytokines to be released from the helper cell)

Question 25

How is complement activated by adaptive immunity?

Answer 25

Through the classical pathway

Question 26

What happens during primary exposure to A?

Answer 26

A small amount of IgM produced

Question 27

What happens during secondary response to A?

Answer 27

More rapid and larger production of IgG

Question 28

What happens when primary exposure to B occurs at the same time as secondary exposure to A?

Answer 28

Small amount of IgM produced (symptoms still occur)

Question 29

What do vaccines do?

Answer 29

Help prime the immune response for future exposure to the viral pathogen

Question 30

What are the components of vaccines?

Answer 30

Antigen and adjuvant

Question 31

What is antigen?

Answer 31

The specific molecule that the immune system may recognise - made using heat killed, attenuated (repeated culture/passage) or recombination viral proteins

Question 32

How does attenuation occur?

Answer 32

Through passage through non-human cells

Question 33

What is adjuvant?

Answer 33

Helps to enhance the immune response against the antigen