Activation of pertussis toxin-sensitive CXCL12 (SDF-1) receptors mediates transendothelial migration of T lymphocytes across lymph node high endothelial cells.
In this study we examined the role of chemokines in regulating T lymphocyte transmigration across the lining high endothelial cells (HEC) of high endothelial venules (HEV). The roles played by CCL21 (SLC), CCL19 (MIP-3 beta, ELC) and CXCL12 (SDF-1) were assessed using an in vitro transendothelial migration culture system, which constitutively supports high levels of lymphocyte transmigration. We determined that transmigration of T lymphocytes across HEC is inhibitable by treatment of the T lymphocytes with pertussis toxin (PTX) (80% inhibition). This was attributed to blockade of Gi-protein coupled receptors of T lymphocytes, since a non-ADP-ribosylating form of PTX had no significant effect on transendothelial migration. Inhibition of Gi-protein-coupled receptors on the endothelium had no effect on T cell transmigration. Treatment of T lymphocytes with a desensitizing concentration of CXCL12 caused a 60% reduction in T lymphocyte migration across HEC, and the CXCR4 antagonist SDF-1P2G reduced transmigration by 40%. Desensitizing concentrations of CCL21 and CCL19 had no significant effects on T lymphocyte transendothelial migration. Homologous desensitization of T lymphocytes to each chemokine was confirmed in a transwell migration assay. An approximately 3-kb mRNA corresponding to rat SDF-1 beta was constitutively expressed in HEC and cell surface CXCL12 was detectable by enzyme-linked immunosorbent assay. Together, these findings support a pivotal role for HEC-expressed CXCL12 and its receptor on T cells in the regulation of T lymphocyte homing to lymph nodes.
Phillips
Rhian
R
Division of Cellular Immunology, National Institute for Medical Research, Mill Hill, London, GB.
Ager
Ann
A
D000246:Adenosine Diphosphate Ribose / Q000378:metabolism; D000818:Animals; D002478:Cells, Cultured / Q000187:drug effects; D054415:Chemokine CCL19; D054421:Chemokine CCL21; D054377:Chemokine CXCL12; D019742:Chemokines, CC / Q000494:pharmacology / Q000502:physiology; D019743:Chemokines, CXC / Q000096:biosynthesis / Q000235:genetics / Q000494:pharmacology / Q000502:physiology*; D002633:Chemotaxis / Q000187:drug effects; D004727:Endothelium / Q000166:cytology; D004797:Enzyme-Linked Immunosorbent Assay; D019206:GTP-Binding Protein alpha Subunits, Gi-Go / Q000187:drug effects / Q000502:physiology; D006801:Humans; D008198:Lymph Nodes / Q000166:cytology*; D051379:Mice; D037342:Pertussis Toxin; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D019718:Receptors, CXCR4 / Q000037:antagonists & inhibitors; D019707:Receptors, Chemokine / Q000187:drug effects / Q000502:physiology; D013601:T-Lymphocytes / Q000187:drug effects*; D010566:Virulence Factors, Bordetella / Q000494:pharmacology*
C515460:CCL19 protein, human; C515478:CCL21 protein, human; C515255:CXCL12 protein, human; C515461:Ccl19 protein, mouse; C515479:Ccl21c protein, mouse; D054415:Chemokine CCL19; D054421:Chemokine CCL21; D054377:Chemokine CXCL12; D019742:Chemokines, CC; D019743:Chemokines, CXC; C515256:Cxcl12 protein, mouse; D012333:RNA, Messenger; D019718:Receptors, CXCR4; D019707:Receptors, Chemokine; C452845:SDF-1P2G; D010566:Virulence Factors, Bordetella; D000246:Adenosine Diphosphate Ribose; D037342:Pertussis Toxin; D019206:GTP-Binding Protein alpha Subunits, Gi-Go