Influenza and Cold

Question 1

What viruses can a cold be caused by?

Answer 1

Rhinovirus - small - enveloped - ss+RNA
Influenza - LARGE - enveloped - ss-RNA
Adenovirus - LARGE - non enveloped - dsDNA
Human coronaviruses

Question 2

Influenza Virus Features

Answer 2

Enveloped
ss-RNA (8 seperate molecules)
Baltimore classification Group V
80-120mm
Haemaglutinin
Neuraminidase

Question 3

What is the genome structure of influenza?

Answer 3

Envelope
Matrix (m1)
Ion channel (M2)
Neuraminidase and haemagglutinin
8 single strand RNA molecules encoding different genes

Question 4

How does Influenza attach and enter a cell?

Answer 4

HA protein mediates attachment to sialic acid and is the taken in via endosomes
Endosome contains proton pumps which gradually decrease the pH of the endosome from 7-5.
M2 ion channel is also a proton pump which channels protons into vision, lowering pH

Question 5

What is sialic acid?

Answer 5

Transmembrane glycoprotein carry sialic acid acts as attachment site (cleaved by neuraminidase)

Question 6

What configurations do

1) Human influenza
2) Avian influenza
3) Swine influenza

Answer 6

1) alpha2, 6 configuration
2) alpha2, 3 configuration
3) either type of linkage so are susceptible to both viruses

Question 7

What does the lowered pH cause?

Answer 7

irreversible conformational change in the H protein, fusion of viral envelope with endosomal membrane

Question 8

How does amantadine affect the m2 ion pump?

Answer 8

Blocks channel preventing it pumping protons into the vision, viral RNAs remain bound to m1 and cannot enter nucleus

Question 9

What is the function of neuraminidase

Answer 9

budding - prevents aggregation of viral particles.

Cleavers neuraminic acid residues from respiratory tract mucins facilitating movement to target cell

Question 10

Adenovirus Receptors

1) what receptors are recognised

Answer 10

1) CAR, CD46 and several integrins.