Immunity Against Infection II

Question 1

How can viruses be EC when usually ic

Answer 1

Early stage of infection before they get into cells

Need complement, ab, phagocytosis, neutralisation,MHC II presentation

Question 2

What is needed once they become ic

Answer 2

MHC I presentation on all cells

Activate th1 to activate CD8 and NK cells

Question 3

What is the first response to viral infection

Answer 3

Type 1 ifn a and ifn b

Question 4

What do ifn a and b induce which prevents viral replication

Answer 4

2’-5’ oligoadenylate synthetase : degrades rna

Kinase PKR : inhibits viral protein synthesis

Question 5

Other than activating oligoadenylate synthetase and kinase pkr, what does ifn a and b do

Answer 5

Upregulate MHC I (stimulate CD8)
Upregulate dendritic and macrophage cells (apc)
Induce NK anti viral response
Induce chemokines to recruit lymphocytes

Question 6

After induction of ifn a and b which stimulates apc and NK, what is released to promote th1 response (CD8 and NK stimulation)

Answer 6

Type II ifn y (from NK cells and apc like macrophages)

Question 7

What is an issue with ifn a used to treat cancers

Answer 7

Can cause too much chemokine/cytokine production forming a storm

Question 8

How do NK cells kill viral cells after stimulation by both ifn a/b and also by ifn y th1 response

Answer 8

Granules with perforin and granzymes

Question 9

Which NK receptors activate them to kill viral cells by releasing granules

Answer 9

Activating receptors (recognise viral cell things like carbohydrates)

Question 10

Which receptors inhibit killing of healthy cells by NK cells

Answer 10

Inhibitory receptors. They when bound non specifically to MHC I will make NK cells not kill it (killed by CD8 instead)

Question 11

Which response comes last to clear viral infections

Answer 11

Cell mediated

Question 12

What activates CD8

Answer 12

Ifn y which stimulates th1 response

Also MHC I presentation

Question 13

Which2 ways do CD8 cells kill viral cells (apoptosis)

Answer 13

Secrete granzymes and perforin

Or binding of its FAS ligand to a Fas on host cell

Question 14

What ensures local release of granules from CD8

Answer 14

Cell to cell contact via cams

Cytoskeleton rearrangements

Question 15

What cytokine do CD8 release important in viral killing

Answer 15

Ifn y

Question 16

Why are antibodies important in viral infections

Answer 16

In early stages before cell entrance.
Antibodies stop adherence eg iga
They cause complement lysis of enveloped viruses
Cause opsonisation via macrophages

Question 17

Which antigens from influenza are used for the vaccine to produce antibodies

Answer 17

Hemagluttinin

Neuraminidase

Question 18

What cells does hiv target

Answer 18

CD4, macrophages and dendrites (leads to opportunistic infections like candida,kaposi sarcoma)

Question 19

Which cells control hiv to an extent

Answer 19

CD8 responses

Question 20

Why is hiv hard to vaccinate

Answer 20

Antibodies don’t protect against it

Question 21

What is dampened down by sars cob 2 which causes cytokine storm instead and viral replication

Answer 21

Ifn type 1

Question 22

Which type of prr are inhibited by covid

Answer 22

Rig 1

Question 23

What pro inflammatory tf is upregulated by covid

Answer 23

Nfkb

Question 24

Why are antibodies important for parasite killing

Answer 24

Allow opsonisation
Adcc - coat large parasites for eosinophil killing via fc receptors
Also can cause lysis via complement

Question 25

Which parasite is killed by igE stimulating eosinophils

Answer 25

Helminths - coated and killed

Question 26

Why is the T cell/macrophage response also important for parasites

Answer 26

Some are intracellular and can survive in vesicles/macrophages

Hidden from antibody response

Question 27

Give an example of a parasite ic so needs macrophages/th1 cell response

Answer 27

Leishmania (stay in macrophages)