Immunology Flashcards
What is the difference between intracellular and extracellular bacteria?
- Intracellular can enter and survive inside the host organism
- Extracellular cannot survive inside the host once the phagocyte is ingested
What is the definition of virulence?
The ability to infect the host and cause disease
What are issues with the evolution of HIV?
The antigenic drift is very rapid and therefore outpaces the development of the immune response which causes disease
How does the flu spread so rapidly?
The recombination of the RNA sequence which further mutates to cause more epidemics
In 1918, what major thing did the Spanish flu do?
Crossed the species barrier
What does altering the surface proteins on a pathogen do?
It means they can avoid host immune response
What is the difference between a primary and a secondary response?
- Primary response takes 7-10 days and is not very strong
- Secondary response takes 4-6 days and is very powerful, memory improves here due to memory cells
What immune response do we depend on in the first few hours/ days?
Innate immunity
What can the immune system check to distinguish between self and non-self at a molecular level?
- Bacterial cell wall
- Protein and peptide structures
- Yeast carbohydrates
- Pathogenic DNA
- Viral antigens on host cells
What tissue uses only it’s own immune response?
The brain, through the blood brain barrier
Why must the immune system give the right amount of response?
Or else it will not clear it or it may damage the host
What are the two types of immune response?
Innate and adaptive
What are mucus layers?
- On epithelial surfaces
-Secreted from mucins and glycoproteins - Slippery so pathogens can’t attach
- Have cilia
What are defensins?
- Hydrophobic domains
- 12-50 aa in length
- positive charge
- in all plants and animals
They kill and inactivate pathogens using an uncertain non-specific mechanism
Why are PAMPs useful?
They look for something different in the body which is recognised by PRRs in the blood
Name 3 classes of PAMPs
- fMet attracts neutrophils
- peptidogylcans from cell walls
- bacterial flagellae
- lipopolysaccharides (LPS)
- mannans, glucans and chitin from fungi
- motifs from bacterial or viral DNA
What do toll receptors do?
Pathogenic fungi bind to repeating motifs which sends signal to nucleus which expresses antifungal defensins.
Basically nucleus feels the signal and inflammatory response is triggered.
Where are toll like receptors found?
- epithelial cells
- macrophages
- dendritic cells
- neutrophils
How old are TLRs and PAMPs believed to be?
1576 million years old
What is evasion?
LPS is replaced with LOS so it is not recognised by immune system and evades it, it mimics a body cell
What are the 3 types of phagocyte?
- Macrophage
- Neutrophil
- Eosinophil
What two types of cell are granulocytes?
Neutrophils and eosinophils
What are neutrophils?
Most common phagocyte which are rapidly recruited but short lived, they have a bright pink nucleus
What are macrophages?
They recognise and remove dead and damaged cells, they are long lived
