Pathogenicity of infection--> influenza II

Question 1

What happens as a result of the globular head binding to sialic acid?

Answer 1

Protein to change shape
Hinge region allows head to move to the surface of the virus

Question 2

Purpose of the hinge region on HA?

Answer 2

Allows the virus to be brought into contact with the surface of the cell thats going to be infected

Question 3

WHich carbohydrates usually precede sialic acid in a cell surface carbohydrate?

Answer 3

Lactose

Question 4

What is sialic acid usually joined to?

Answer 4

Galactose

Question 5

Initial response to influenza infection?

Answer 5

Innate response–> general, broad, inflammatory

Question 6

Which substance is upregulated in response to an influenza infection?

Answer 6

NFkappabeta

Question 7

What does upregulation of NFkappabeta lead to?

Answer 7

Broad pro-inflammatory response–> expression of TNFalpha, interferons, interleukins– IL8

Question 8

Role of cytokines upregulated by NFkappabeta upregulation?

Answer 8

Act on other immune cells–> NK, T and B cell activation

Question 9

Where are the immune cells recruited to in an influenza infection?

Answer 9

Lungs

Question 10

Long term influenza response?

Answer 10

Th2 response, T cell stimulation, B cell maturation

Question 11

What do antigen stimulation and t cell activation lead to?

Answer 11

B cell maturation

Question 12

How is B cell maturation a pathogen-specific response?

Answer 12

Presentation of antigens from the influenza virus are used to mature B cells to produce specific IgG antibodies

Question 13

If the long term influenza response is so successful, why do people keep catching it?

Answer 13

Many diff types of influenza

Question 14

Diff types of influenza?

Answer 14

A, B, C, D strains

Question 15

Which strains of influenza are the key ones that cause seasonal epidemics every year?

Answer 15

A and B

Question 16

Which animal does influenza D primarily affect?

Answer 16

Cattle

Question 17

What are diff influenza serotypes distinguished by?

Answer 17

Particular proteins on their surface–> HA and A as

Question 18

Which influenza protein can have diff types?

Answer 18

HA and NA

Question 19

How many diff subtypes of HA are there?

Answer 19

18

Question 20

How many diff subtypes of NA are there?

Answer 20

11

Question 21

What are the current subtypes of influenza A viruses found in people?

Answer 21

H1N1, H3N2

Question 22

What is antigenic drift?

Answer 22

Gradual accumulation of mutations in AAs over time

Question 23

What happens if the mutation occurs in a region of the influenza genome that codes for HA or NA?

Answer 23

Antibodies will no longer bind

Question 24

Seasonal influenza rate?

Answer 24

50 cases per 100,000/week

Question 25

Why are new variants of seasonal influenza derived from a past strain?

Answer 25

Most come about from antigenic drift and so will be similar

Question 26

Why does seasonal influenza not cause similar mortality rates to that of pandemic influenza?

Answer 26

Have some immunity as most strains are similar to that of past seasonal strains

Question 27

How can we prepare for seasonal influenza?

Answer 27

Anticipate a likely strain to emerge and prepare a vaccine beforehand

Question 28

How does pandemic influenza come about?

Answer 28

Antigenic shift

Question 29

What is antigenic shift?

Answer 29

Changes to the entire gene--> codes for an entirely diff protein

Question 30

How does antigenic shift work in influenza?

Answer 30

Host is coinfected w/ two diff strains Both strains infect the same cell Both release their RNA--> can mix the RNA between them to give an entirely new HA and NA combination

Question 31

In which animals does antigenic shift usually occur in?

Answer 31

Pigs, chickens, birds etc

Question 32

What can follow antigenic shift?

Answer 32

Antigenic drift

Question 33

Main issue w/ antigenic shift?

Answer 33

Random, unpredictable and have no immunity against it