The Cells involved in inflammation Flashcards
What is inflammation?
A local protective response to eliminate the initial cause of tissue cell injury as well as necrotic cells resulting from the initial insult
What are the 5 pillars of inflammation?
- Heat
- Redness
- Swelling
- Pain
- Loss of function
What are the roles of inflammation?
- Alert the body to infection and injury
- Regulate influx of leukocytes that can resolve the injury
- Facilitate immune responses
- Dilute noxious components
- Remove damaged tissue
- Initiate the tissue repair process
What are the orchestrators of inflammation?
- Tissue resident macrophages and mast cells
- Blood vessel endothelial cells
- Soluble components released by immune cells at site of infection
- Soluble components in serum
What are the effects of TNF-α and IL-1 on endothelial cells in blood vessels?
- Endothelial cells retract
- Causes increase in vascular permeability
- Blood vessels dilate
- Blood flow slowed
What is the principal role of mast cells?
To act as communication cells
What cells recognise tissue damage in the inflammatory response?
Macrophages and mast cells
Why are blood cells made leaky by the inflammatory response?
It makes it easier for additional immune cells to move from the blood to the site of inflammation
Outline how immune cells leave the blood
- Rolling on the walls of the blood vessels
- Adhesion and transmigration
- Migration through tissues towards chemotactic stimulus
What is the normal velocity of a cell in the blood?
4000um/s
What is the velocity of an immune cell when it is rolling?
40um/s
What kind of chemicals are involved in the process of rolling?
Selectins
What is the role of selectins?
They mediate the process of rolling by binding to selected carbohydrate groups
What are the 3 types of selectin?
- E-selectin
- P-selectin
- L-selectin
Where is E-selectin found?
On the endothelium
Where is P-selectin found?
On platelets and the endothelium
Where is L-selectin found?
On leukocytes
What is the seqeuence of events in acute inflammation?
- Oedema
- Neutrophil recruitment
- Monocyte/macrophage recruitment
What is a catch bond?
A bond that strengthens under force
What type of selectins are upregulated by inflammatory mediators?
E and P
What does L-selectin bind to?
CD34
Outline the process of rolling
- E and P selectins are upregulated by inflammatory mediators
- These bind glycoproteins on leukocyte
- L-selectin binds CD34 on the endothelium
- Due to selectin binding leukocytes roll on the blood vessel walls
What is chemotaxis?
The cellular migration up a concentration gradient of a diffusable protein
Where is CXCL8 (IL-8) produced in acute inflammation?
The endothelium
Which chemokine is produced in chronic inflammation?
CCL2
Which chemokine is produced in acute inflammation?
CXCL8 (IL-8)
What is an integrin?
A protein which mediates tight adhesion of blood vessels and leukocytes
Give 3 examples on integrins
- LFA-1
- VLA-4
- Mac-1
What is the ligand of LFA-1?
ICAM-1
What is the ligand of VLA-4?
VCAM-1
Where is VLA-4 found?
On mucosal T cells
What is the ligand of Mac-1?
It has over 40 reported ligands including ICAM-1
What increases expression of ICAM-1 and VCAM-1?
TNF-α and IL-1
