2. The Cellular Response. Flashcards
How do we recognise neutrophils?
They have segmented nuclei and this gives it the appearance of having multiple lobes.
How do we recognise eosinophils?
They contain large red/pink granules.
How do we recognise basophils?
They contain large blue granules within them and they look like a blueberry.
Where are mast cells found?
Only in the blood.
How do we recognise mast cells?
They have very small granules which can often be seen extracellularly.
What kind of immune cells have a kidney bean shaped nucleus within them?
Monocytes and macrophages.
What is the difference between monocytes and macrophages?
Monocytes are found in the blood.
Macrophages are found in the tissue.
How do we recognise lymphocytes?
They have nuclei located on one side.
Are lymphocytes plasma cells?
Yes (B and T cells).
Where are neutrophils produced?
In the bone marrow.
How long does it take for neutrophils to respond to a stimulus?
They respond very quickly.
How do neutrophils kill pathogens?
By phagocytosis
By releasing granules that kill pathogens.
Do neutrophils have intracellular or extracellular killing?
Both.
Are neutrophils long lived?
No, once they are released into the blood they circulate for around 10 hours before they die.
Do neutrophils survive longer in blood or tissue?
In tissue.
What are the 3 primary granules of neutrophils?
Myeloperoxidase.
Defensins.
Meutral proteases.
What are the 4 secondary granules of neutrophils?
Lactoferrin.
Collagenase.
Plasminogen activator.
Histaminase.
Can the granules released by neutrophils damage the host?
Yes.
What are neutrophil extracellular traps?
Traps similar to a spiders web where they can trap and kill pathogens.
Why would you see immature and mature neutrophils at the site of infection?
Because the body overcompensates and releases band neutrophils.
This is a regenerative left shift.
What is degenerative left shift.?
When there are more band neutrophils than segmented neutrophils at an infection site.
This is a sign of serious infection.
A degenerative left shift is commonly seen in what animals?
Cattle.
Why do we commonly see degenerative left shifts in cattle?
As they cannot produce as many neutrophils as other species.
What is the sight of band neutrophils normal in?
Cattle.
What cells are generally seen in an acute infection?
Neutrophils.
Where are eosinophils produced?
In the bone marrow.
What are the 2 main functions of eosinophils?
Allergy response.
Parasite killing.
What is the main way that eosinophils eliminate pathogens?
De-granulation.
They do not phagocytose.
What is produced by the body to tell the bone marrow that there is a parasitic infection.
Histamine.
IL-5.
Why does the body produce histmaine and IL-5 when there is a parasitic infections?
It tells the bone marrow to produce more eosinophils.
What 2 ways do eosinophils navigate to a parasite?
They use a chemokine called eotaxin.
Plasma cells opsonise the parasite with IGE which attracts eosinophils.
What is produced by the body to tell the bone marrow that there is an allergic reaction?
Histamine.
A small amount of IL-5.
How do eosinophils navigate from the bone marrow to the site of an allergic reaction?
They use a chemokine called eotaxin.
Plasma cells tag any allergens with IGE.
What is the major differende in eosinophil activation in allergies and parasitic infections?
In parasitic infections the body produces IL-5 and histamine.
In allergies there is more histamine produced than IL-5.
When do idiopathic eosinophilic lesions occur?
When eosinophils get into tissues.
What is the key finding in idiopathic eosinophilic lesions?
The presence of eosinophils without any parasite/allergen present.
What are the 3 presentations of feline eosinophilic granuloma complex?
Eosinophilic plaques.
Eosinophilic granulomas.
Eosinophilic ulcers.
What is cahracteristic about eosinophilic plaques associated with feline eosinophilic granuloma complex?
They are small skin ulcerations which produce a lot of puss.
What is cahracteristic about eosinophilic granulomas associated with feline eosinophilic granuloma complex?
Elevated lesions that are often found on the thighs.
What is cahracteristic about eosinophilic ulcers associated with feline eosinophilic granuloma complex?
Round ulcerations on the lips.
Are oral eosinophilic granulomas found in dogs?
Yes.
They can also be found on the skin.
What condition causes white nodules in the saddle area of a horse?
A collagenolytic granuloma.
It may be caused by a hypersensitivity reaction.
Why are oral lesions of clinical concern?
These can prevent eating, drinking and breathing.
They can be a location for secondary bacterial infections.
What is eosinophilic myositis in dogs?
Where the temporalis and masseter muscles contain type 2M myosin which is targeted by antibodies.
This causes these muscles to waste away.
What animals are affected by eosinophilic myostitis of cardiac muscle?
Sheep and goats.
What is eosinophilic myostitis characterised by in sheep or goats?
Eosinophilic infiltration of skeletal and cardiac muscle.
This can be incidental or a cause of sudden death.
Are basophils and mast cells found in high concentrations compared to other red blood cells?
No.
How do basophils and mast cells help with inflammation?
They help via cellular mediation.
Where are mast cells found?
In the mucosa and connective tissue.
Where are basophils found?
In the blood.
What is the function of basophils and mast cells?
They carry out antigen surveillance and release effector mediators such as histamine and heparin.
Do basophils and mast cells respond to infections quickly or slowly?
Quickly.
What is the role of natural killer cells?
They kill infected cells and tumour cells.
Are B cells, T cells and natural killer cells involved in acute or chronic infections?
Chronic infections.
What activates a helper T cell?
Antigen presentation.
What happens once a helper T cell has been activated?
They produce cytotoxic T cells which use the antigens to recognise infected cells.
Once they find these cells they kill them.
How do T cells kill infected cells?
By releasing cytotoxins that trigger apoptosis.
Do neutrophils or T cells produce damage to host cells?
Neutrophils.
Large amounts of lymphocytes in the blood tell you what 2 things about an infection?
That it is a chronic condition.
That it is an intracellular pathogen causing the infecxtion.
What 3 things make NKCs unique?
They can recognize injured cells without MHC-1 processed antigens.
They secrete perforin and granzyme.
They can form antigen-specific
memory.
What are the 3 roles of macrophages in inflammation?
Phagocytosis.
Antigen presentation.
Iron sequestration.
What are multi-nucleated giant cells?
A collection of macrophages.
If something is difficult to phagocytose then macs clump together and phagocytose it.
What is a Kupffer cell?
A macrophage in the liver.
What is a Langerhans cell?
A macrophage in the epidermis.
What is a microglial cell
A macrophage in the brain.
What is a hofbauer cell?
A macrophage in the placenta.
What are osteoclasts?
Macrophages in the bone.
What is anaemia of chronic diseases?
When anaemia occurs as macrophages sequester all the iron.
This prevents the body from making new red blood cells.
What can we tell about an infection if lots of macrophages are responding to the infection?
That the body is having a hard time getting rid of the infection.
Whay are plasma cells always present when eosinophils are made?
As they produce the IGE that attracts eosinophils to the injury site.
