Infleunza Flashcards

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1
Q

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

A

A

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2
Q

What does B and C cause

A

Milder disease in humans

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3
Q

How is influenza transmitted

A

Respiratorily

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4
Q

Which types of cells are killed by influenza

A

Ciliated epithelial cells

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5
Q

What happens to mucus because of lysed ciliated cells

A

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

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6
Q

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

A

Macrophages phagocytose the infected cell

This release cytokines which cause inflammation

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7
Q

What symptom do cytokines cause and why

A

Leaky nose

Because they act on endothelial cells in the nose

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8
Q

What causes fever

A

Pyrogens which cause cytokines to act on hypothalamus and increase temperature

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9
Q

Why is a cough a symptom

A

Build up of mucus

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10
Q

What are the 2 innate responses to influenza

A

Natural killer NK cells

And

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

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11
Q

What are the 2 adaptive responses to influenza

A

B cells which produce antibodies

T cells which produce CD8 cytotoxic and CD4 helper cells

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12
Q

What is the difference between mucosal and system immunity

A

Mucosal-

Causes production of IgA antibody

Systemic -

Causes production of igG to protect mucosal surfaces

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13
Q

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

A

When cytokines cause leaky nose by acting on endothelial cells

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14
Q

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

A

Waning immunity

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15
Q

Explain the genome of influenza

A

8 ss rna (-) (antisense)

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16
Q

Which 2 proteins are within the genome of influenza

A

Nucleoproteins

Rna dependant rna polymerase (for rep and transcription)

17
Q

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

A

PA
PB1
PB2

18
Q

How many matrix protein types are there

A

2

M1 and M2

19
Q

Which protein forms pores in the envelope

A

M2

20
Q

What are the 2 types of glycoproteins on surface of influenza

A

Haemogglutinin

Neuraminidase

21
Q

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

A

Sialic nana acid

22
Q

How does haemogglutinin binding to nana cause entry

A

Receptor mediated endocytosis into a vesicle

23
Q

How does fusion of envelope with vesicle occur

A

Endosomes with Protons fuse with vesicles

H moves in via the M2 pores

Causes a conformational change which causes fusion

24
Q

What happens when rna dep rna pol and rna genome released

A

Rna is transcribed into mrna +

Via rna dep rna pol

25
Q

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

A

Produce new rna - strand copies for the new genome

26
Q

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

A

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

27
Q

How is budding off allowed by neuraminidase

A

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

28
Q

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

A

Rna dep rna polymerase

29
Q

What is the difference between antigenic shift and drift

A

Antigenic drift is gradual mutation causing an epidemic

Antigenic shift is complete reassortment of genome causing a pandemic

30
Q

What 2 things change in antigenic shift and drift

A

Haemogglutinin and neuraminidase

31
Q

How does reassortment occur (antigenic shift)

A

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

32
Q

Why was the 1918 strain prominent in young people

A

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

33
Q

What 2 types of vaccines are there

A

Killed : where the killed virus is a administered

Live attenuated : live but non infectious

34
Q

What 2 types of therapies are there for influenza

A

Amantidine - M2 pore channel blocker which stops fusion with vesicles

Tamiflu- inhibit neuraminidase so budding can’t occur