Flashcards in Influenza and Cold Deck (10)
What viruses can a cold be caused by?
Rhinovirus - small - enveloped - ss+RNA
Influenza - LARGE - enveloped - ss-RNA
Adenovirus - LARGE - non enveloped - dsDNA
Influenza Virus Features
ss-RNA (8 seperate molecules)
Baltimore classification Group V
What is the genome structure of influenza?
Ion channel (M2)
Neuraminidase and haemagglutinin
8 single strand RNA molecules encoding different genes
How does Influenza attach and enter a cell?
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
What is sialic acid?
Transmembrane glycoprotein carry sialic acid acts as attachment site (cleaved by neuraminidase)
What configurations do
1) Human influenza
2) Avian influenza
3) Swine influenza
1) alpha2, 6 configuration
2) alpha2, 3 configuration
3) either type of linkage so are susceptible to both viruses
What does the lowered pH cause?
irreversible conformational change in the H protein, fusion of viral envelope with endosomal membrane
How does amantadine affect the m2 ion pump?
Blocks channel preventing it pumping protons into the vision, viral RNAs remain bound to m1 and cannot enter nucleus
What is the function of neuraminidase
budding - prevents aggregation of viral particles.
Cleavers neuraminic acid residues from respiratory tract mucins facilitating movement to target cell