Immune Cell migration and inflammation Flashcards
Where do T-cell translocate from and to?
T-Cells translocate from circulation into epithelium
What is the 4 stage process of T-cell translocation from circulation to epithelium?
1) Rolling/tethering (T-cells slow down in blood)
2) Activation
3) Adhesion
4) Transmigration
What are the three selectin molecules
L,P and E
How do T-cells translocate from circulation to epithelium?
1)T-cells are slowed down by L,P and E selectins.
2)
What activates intergrins on T-cells?
Chemokines
What is lymphocyte homing?
trafficking of naive T and B
lymphocytes to secondary lymphoid organs in lymph nodes, Peyer’s patches, tonsil this
requires active migration across blood vessels
• Entry into secondary lymphoid organs is highly
selective for lymphocytes
• Egress from lymphoid organs involves distinct
molecular mechanisms from entry
What are the effects of cytokines on vascular permeability?
Cytokines cause increase in vascular permeability
leading to local swelling, increased entry of
antibody, complement, etc.
What effects do cytokines have on cellular adhesion molecules?
Cytokines cause increased expression of adhesion
molecules on vascular endothelium and these
work together with chemokines to recruit cells -
neutrophils, monocytes, NK cells and, later,
effector lymphocytes.
What are selectins?
Selectins are calcium-dependent (C-type)
lectins (carbohydrate binding proteins)
What is the role of L-selectins?
L-selectin promote entry to LNs, PPs–on lymphocytes (neutrophils)–
binds specialized sulfated mucins (‘peripheral node
addressins’or PNAd) made by high endothelial venules
(HEV
What is the structure of lectins?
C-type lectin domain EGF-Like domain Consensus repeats Transmembrane region Cytoplasmic domain
What is the role of P-Selectins?
Early role in entry to site of inflammation–in
Weibel-Palade bodies in endothelial cells and a-granules of
platelets–translocates to membrane in response to
thrombin, histamine, C5a, etc–binds PSGL-1, a tyrosine
sulfated mucin present on neutrophils, some effector T
cells
What is the role of E selectins?
-delayed role in entry to site of inflammation–
cytokine inducible on endothelial cells (especially
cutaneous)–binds carbohydrate ligand (sialyl-Lex) on
neutrophil and effector T cell glycoproteins /glycolipids
What cells are LFA-1 (αLβ2) intergrins expressed on?
What are the LFA-1 (αLβ2) ligands?
1) Lymphocytes, DCs , NK cells, neutrophils
2) ICAMs (1–5),JAM-1
What cells are Mac-1 (αMβ2) intergrins expressed on ?
What are its Ligands?
1)Neutrophils, monocytes, macrophages, dendritic
cells, lymphocytes, NK cells
2) ICAMs (1, 2, 4), fibrinogen, C3bi, factor X,
