Infleunza

Question 1

Which influenza strain can affect animals like pigs birds and humans and is most severe

Answer 1

A

Question 2

What does B and C cause

Answer 2

Milder disease in humans

Question 3

How is influenza transmitted

Answer 3

Respiratorily

Question 4

Which types of cells are killed by influenza

Answer 4

Ciliated epithelial cells

Question 5

What happens to mucus because of lysed ciliated cells

Answer 5

It can’t get dislodged and there’s a build up of mucus in the respiratory tract (upper)

Question 6

What is the first thing that happens due to lysed ciliated cells (our immune response)

Answer 6

Macrophages phagocytose the infected cell

This release cytokines which cause inflammation

Question 7

What symptom do cytokines cause and why

Answer 7

Leaky nose

Because they act on endothelial cells in the nose

Question 8

What causes fever

Answer 8

Pyrogens which cause cytokines to act on hypothalamus and increase temperature

Question 9

Why is a cough a symptom

Answer 9

Build up of mucus

Question 10

What are the 2 innate responses to influenza

Answer 10

Natural killer NK cells

And

Type 1 interferons IFN which allow resistance of other cells around infected

Question 11

What are the 2 adaptive responses to influenza

Answer 11

B cells which produce antibodies

T cells which produce CD8 cytotoxic and CD4 helper cells

Question 12

What is the difference between mucosal and system immunity

Answer 12

Mucosal-

Causes production of IgA antibody

Systemic -

Causes production of igG to protect mucosal surfaces

Question 13

When is igG produced to protect mucosal surface in the systemic immunity

Answer 13

When cytokines cause leaky nose by acting on endothelial cells

Question 14

What is the type of immunity the systemic and mucosal immunity produce via iga and igG

Answer 14

Waning immunity

Question 15

Explain the genome of influenza

Answer 15

8 ss rna (-) (antisense)

Question 16

Which 2 proteins are within the genome of influenza

Answer 16

Nucleoproteins

Rna dependant rna polymerase (for rep and transcription)

Question 17

What are the 3 types of proteins which produces rna dep rna pol

Answer 17

PA
PB1
PB2

Question 18

How many matrix protein types are there

Answer 18

2

M1 and M2

Question 19

Which protein forms pores in the envelope

Answer 19

M2

Question 20

What are the 2 types of glycoproteins on surface of influenza

Answer 20

Haemogglutinin

Neuraminidase

Question 21

What does gp haemogglutinin bind to on ciliated epithelial cells for entry

Answer 21

Sialic nana acid

Question 22

How does haemogglutinin binding to nana cause entry

Answer 22

Receptor mediated endocytosis into a vesicle

Question 23

How does fusion of envelope with vesicle occur

Answer 23

Endosomes with Protons fuse with vesicles

H moves in via the M2 pores

Causes a conformational change which causes fusion

Question 24

What happens when rna dep rna pol and rna genome released

Answer 24

Rna is transcribed into mrna +

Via rna dep rna pol

Question 25

What are rna + copies used for other than translation of structural proteins

Answer 25

Produce new rna - strand copies for the new genome

Question 26

What happens once the GP Neuraminidase and haemogglutinin are glycosylated at Golgi

Answer 26

Transfer to the cell membrane where all other proteins and new rna - strands assemble to form and bud off a new virus

Question 27

How is budding off allowed by neuraminidase

Answer 27

It cleaves sialic acid to stop the binding of haemogglutinin in the new virions

Question 28

What catalyses the production of new rna (-) from mrna +

Answer 28

Rna dep rna polymerase

Question 29

What is the difference between antigenic shift and drift

Answer 29

Antigenic drift is gradual mutation causing an epidemic Antigenic shift is complete reassortment of genome causing a pandemic

Question 30

What 2 things change in antigenic shift and drift

Answer 30

Haemogglutinin and neuraminidase

Question 31

How does reassortment occur (antigenic shift)

Answer 31

If another host becomes infected with 2 diff strains eg bird and human strain infect pig The strains then mix in genome to produce new sets of proteins eg new gp

Question 32

Why was the 1918 strain prominent in young people

Answer 32

Because they have higher immune response they produce more cytokines which cause bad effects like fever

Question 33

What 2 types of vaccines are there

Answer 33

Killed : where the killed virus is a administered Live attenuated : live but non infectious

Question 34

What 2 types of therapies are there for influenza

Answer 34

Amantidine - M2 pore channel blocker which stops fusion with vesicles Tamiflu- inhibit neuraminidase so budding can’t occur