Case Study 1 Freshers Flu Flashcards
What receptors on influenza virus attach to cell
Haemagluttin receptors
What does haemagluttin bind to on the surface of the cell
Sialic acid
Which type of cells does influenza bind to
human respiratory endothelial cells
By what process does influenza enter the cell
endocytosis
What enzyme does influenza use to leave the cell
neuraminidase
Which variant antigens do vaccinations use to target influenza
neuraminidase and Haemagluttin
What are the different types of influenza
Influenza a, b and c
Which cell types is sialic acid found on?
erythrocytes, upper airway and lung endothelial cell membranes
What does the binding of haemagluttin to sialic acid result in
haemmagglutination - this creates a network of interconnected RBCs and virus particles
What does neuraminidase do
Its a glycoside hydrolase enzyme that cleaves the sialic acid groups from glycoproteins
What is antigenic drift
natural mutation over time of a known strain resulting in small genetic changes
How might antigenic drift lead to loss of immunity of vaccine mismatch
Accumulation of small genetic changes over time can lead to viruses with slightly different antigenic material
What is antigenic shift
abrupt or major change in genetic material
Which influenza virus does antigenic shift occur in
influenza A
How does antigenic shift occur
two or more strains of a virus infect the same cell and their genetic material combine to product progeny with new HA/NA combinations
Why does antigenic shift only occur in influenza a
As human and avian influenza A is able to infect pigs (not seen with other strains)
Why are genetic changes more common in RNA
Don’t have the same proof reading mechanism as DNA
What are the 5 different types of vaccines
Viral vector vaccine, DNA vaccine, RNA vaccine, Live-attenuated vaccine, protein-ased vaccine
What happens in viral vector vaccines
surface protein gene injected, different live replicating or non replicating virus engineered to carry gene, viral vector transcried engineered gene in the cytoplasm (or enters nucleus for transcriptions)
What happens in DNA vaccine
plasmid is synthesised to encode for gene of surface protein injected, enters nucleus of cell
What happens once viral vector and DNA vaccine enter the nucleus
DNA is transcribed into mRNA