title: The S1P-analog FTY720 differentially modulates T-cell homing via HEV: T-cell-expressed S1P1 amplifies integrin activation in peripheral lymph nodes but not in Peyer patches.
abstract: Sphingosine-1-phosphate (S1P) and its receptor S1P1 control T-cell egress from thymus and secondary lymphoid organs (SLOs). To further define the role of S1P1 in lymphocyte trafficking, we performed adoptive transfer experiments and intravital microscopy (IVM) using both S1P1-/- lymphocytes and recipient wild-type (WT) mice treated with FTY720, an immunosuppressant that downmodulates S1P receptors. S1P1 deficiency and FTY720 caused rapid disappearance of T cells from blood, prolonged retention in SLOs, and accumulation in bone marrow, but did not alter interstitial T-cell motility in peripheral lymph nodes (PLNs) as assessed by multiphoton IVM. However, S1P1-/- lymphocytes displayed reduced short-term homing to PLNs due to attenuated integrin-mediated firm arrest in high endothelial venules (HEVs). By contrast, S1P1-/- T cells homed normally to Peyer patches (PPs), whereas S1P1-/- B cells had a marked defect in homing to PPs and arrested poorly in PP HEVs. Therefore, S1P1 not only controls lymphocyte egress from SLOs, but also facilitates in a tissue- and subset-specific fashion integrin activation during homing. Interestingly, FTY720 treatment enhanced accumulation of both S1P1 sufficient and S1P1-/- T cells in PPs by enhancing integrin-mediated arrest in HEVs. Thus, FTY720 exerts unique effects on T-cell traffic in PPs that are independent of T-cell-expressed S1P1.
authors.affiliation: The CBR Institute for Biomedical Research, 200 Longwood Ave, Boston, MA 02115, USA.
authors.forename: Cornelia
authors.initials: C
authors.lastname: Halin
authors.forename: M Lucila
authors.initials: ML
authors.lastname: Scimone
authors.forename: Roberto
authors.initials: R
authors.lastname: Bonasio
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Gauguet
authors.forename: Thorsten R
authors.initials: TR
authors.lastname: Mempel
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Quackenbush
authors.forename: Richard L
authors.initials: RL
authors.lastname: Proia
authors.forename: Suzanne
authors.initials: S
authors.lastname: Mandala
authors.forename: Ulrich H
authors.initials: UH
authors.lastname: von Andrian
mesh_terms: D019264:Adoptive Transfer; D000818:Animals; D002634:Chemotaxis, Leukocyte / Q000187:drug effects* / Q000502:physiology; D000068876:Fingolimod Hydrochloride; D007166:Immunosuppressive Agents / Q000276:immunology / Q000494:pharmacology*; D016023:Integrins / Q000378:metabolism; D008198:Lymph Nodes; D042601:Lymphatic Vessels; D018655:Lymphocyte Count; D008214:Lymphocytes; D008246:Lysophospholipids / Q000172:deficiency / Q000276:immunology / Q000502:physiology*; D051379:Mice; D018345:Mice, Knockout; D018715:Microscopy, Video; D010581:Peyer's Patches; D011409:Propylene Glycols / Q000276:immunology / Q000494:pharmacology*; D013110:Sphingosine / Q000031:analogs & derivatives* / Q000172:deficiency / Q000276:immunology / Q000502:physiology; D013601:T-Lymphocytes / Q000187:drug effects / Q000502:physiology*
chemical_list: D007166:Immunosuppressive Agents; D016023:Integrins; D008246:Lysophospholipids; D011409:Propylene Glycols; C060506:sphingosine 1-phosphate; D000068876:Fingolimod Hydrochloride; D013110:Sphingosine