Mechanisms Of Leukoctyes Migration To The Site Of Inflammation

Question 1

What is margination?

Answer 1

The process by which leukocytes don’t travel in the centre of the lumen of blood vessels, but rather around the borders.

Question 2

Why do leukocytes travel on the borders of blood vessels?

Answer 2

So they can move slowly and roll and adhere to endothelial cells and then initiate a process of transmigration across the capillary wall

Question 3

What is the process of leukocyte transmigration across endothelial cells called?

Answer 3

Diapedesis

Question 4

Phagocytes are driven to the inflammed tissue by a process called…

Answer 4

Chemotaxis

Question 5

Which are the principal leukocytes in inflammation?

Answer 5

Neutrophils and monocytes

Question 6

What mediated the adhesion between leukocytes and endothelial cells?

Answer 6

Cell surface molecules. Molecules on the leukocyte’s surface bind to molecules on the endothelial surface. Ligand-receptor systems

Question 7

List and describe the molecular interations which can fascilitate adhesion and extravasation

Answer 7

• chemokine and chemokine receptors (preceeding adhesion and extravasation)
• Selectins (bind sugar molecules)
• INTEGRINS (expressed constitutively and have a major role in adhesion; their absence results in NO inflammatory process)

Question 8

The integrin system is a major controller of…

Answer 8

Inflammation

Question 9

Describe the transcriptional vs non-transcriptional control which integrins can have

Answer 9

Transcriptional control - stimuli that come from injured tissue increase the level of their expression in cells (meaning more leukocytes migrate to injury)

Post-transcriptional control - inside out signalling pathway. A signal from inside the cell (a chemokine) can cause a conformational change in the integrin on the surface - from an inactive to an active conformation - able to bind ligand