Lecture 3 - Leukocyte Ciruclation and Migration into Tissue Flashcards
Define migration and homing with regards to leukocytes.
L3 S3
Migration:
-movement of leukocyte from blood to tissue
Homing:
-migration of leukocyte into peripheral tissues to the site of an infection or injury
What are the steps of leukocyte recruitment?
What molecules play a role in this process?
L3 S5
Steps:
- Tethering: loose interaction between leukocyte selectin molecules
- Rolling: slowing of leukocyte and allows chemokines to bind receptors; activates integrins
- Adhesion and stop: activated integrins bind ligand on endothelium
- Transmigration
What are the different classifications of selectins, what is their ligand, and where are they expressed?
L3 S7-8
P-selectin:
- ligand: sialyated carbohydrates related to Lewis family (PMNs, monocytes, or T cells)
- location: activated endothelium (activated by histamine or thrombin)
E-selectin:
- ligand: sialyated carbohydrates related to Lewis family (PMNs, monocytes, or T cells)
- location: activated endothelium (activated by TNF or IL-1)
L-selectin:
- ligand: located on HEVs
- location: leukocytes and lymphocytes
What are the main types of integrins, what are their ligand, and where are they located?
L3 S10-11
LFA-1:
- ligand: ICAM-1/2 (activated endothelium)
- location: all leukocytes
Mac-1:
- ligand: ICAM-1/2 (activated endothelium)
- location: PMNs, monocytes, DCs
VLA-4:
- ligand: VCAM-1
- location: monocytes and T cells
α4β7 integrin:
- ligand VCAM-1 and MadCAM-1
- location: monocytes and gut homing lymphocytes
Chemokines are a specific type of cytokine that stimulate chemotaxis of leukocytes.
Just a reminder
What are the main chemokines in leukocyte migration? Where are they located and what cells do they attract?
L3 S22
IL-8 (activated endothelium):
-recruits neutorphils
MCP-1 (activated endothelium):
-recruits monocytes
CCL19/21 (HEVs):
-recruits naïve T cells
CXCL10 (peripheral infection sites):
-recruits effector T cells
