File:Lymph node - high endothelial venule.jpg

Lymph Node - Lymphocyte Migration at High Endothelial Venule Model

Chemokines and chemokine-binding molecules expressed in and around high endothelial venules (HEVs) in a concentric manner might function coordinately in lymphocyte trafficking across HEVs.

Original authors^[1] propose that several chemokine-binding molecules are expressed in a concentric manner in HEVs and their surrounds. The coordinated actions of chemokines and chemokine-binding molecules in and around HEVs are shown in the above cartoon in sequential order.

• a - In the lumen of HEVs
  • heparan sulphate proteoglycans (red) can capture and present a lymphoid chemokine (X, green) in situ.
  • Duffy antigen receptor for chemokines (DARC; black) — a non-signalling chemokine receptor — captures and scavenges inflammatory chemokines, such as CXC-chemokine ligand 1 (CXCL1; pink), which is constitutively produced by HEVs.
• b - In the basal lamina of HEVs
  • another chemokine-binding protein MAC25 (dark blue) can capture a chemokine, such as CC-chemokine ligand 21 (CCL21), CXCL10 or CCL5 (Y, light blue).
  • In addition, other components in the basal lamina such as collagen and fibronectin (grey) can capture a different chemokine (Z, yellow) expressed in the HEV area.
• c - Lymphocytes rolling along the HEV endothelium
  • recognize chemokine X presented in the lumen
  • signalled to activate their integrins and firmly adhere to HEVs.
• d - Some adhering lymphocytes
  • migrate across HEVs and are stimulated by chemokine Y, which is immobilized on MAC25.
• e - Farther outside
  • other chemokine-binding molecules, such as collagen IV and fibronectin, can capture a different chemokine (Z).
  • Some of the extravasating lymphocytes might interact with chemokine Z and be stimulated to move into this area.
• f - By sequentially recognizing the multiple chemokines presented on the tissue matrix
  • more and more lymphocytes extravasate and progressively move from the inside to the outside of HEVs.

See also Lymph node cartoon and Lymphocyte Migration Movies.

OMIM Links

• CCL21 - CC-chemokine ligand 21
• CXCL10 - Chemokine CXC motif
• DARC - Duffy antigen receptor for chemokines
• MAC25 - Insulin-like growth factor (IGF)-binding protein 7

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Reference

Copyright

Adapted by permission from Macmillan Publishers Ltd: Nat. Rev. Immunol.: 2004, 4(5);360-70, copyright (2004)

Licensee: Mark A Hill License Number: 2857291045727 Publication: Nature Reviews Immunology

Title: Lymphocyte trafficking across high endothelial venules: dogmas and enigmas Type Of Use: post on the internet

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