title: Chemokine receptor expression defines heterogeneity in the earliest thymic migrants.
abstract: Chemokine signaling has been implicated in directing colonization of the fetal thymus by hematopoietic precursors. However, the patterns of expression of the chemokine receptors responsible for directing thymic colonization by the earliest thymic migrants remain unknown. We have identified heterogeneity within the earliest thymus seeding cells based on chemokine receptor expression. By analyzing the first wave of progenitors to colonize the thymus at E12 of gestation, we show that multiple chemokine receptors are expressed by T-lymphoid precursors present within perithymic mesenchyme, while expression of chemokine ligands is limited to CCL21, CCL25 and CXCL12, which are located in distinct epithelial and mesenchymal compartments of the thymic/parathyroid anlagen. Collectively, these results identify multiple populations of T-lymphoid precursors colonizing the fetal thymus and provide evidence for several potential pathways mediating migration of precursors into the embryonic thymus.
authors.affiliation: MRC Centre for Immune Regulation, Institute for Biomedical Research, University of Birmingham Medical School, Birmingham, UK.
authors.forename: William E
authors.initials: WE
authors.lastname: Jenkinson
authors.forename: Simona W
authors.initials: SW
authors.lastname: Rossi
authors.forename: Sonia M
authors.initials: SM
authors.lastname: Parnell
authors.forename: William W
authors.initials: WW
authors.lastname: Agace
authors.forename: Yousuke
authors.initials: Y
authors.lastname: Takahama
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Jenkinson
authors.forename: Graham
authors.initials: G
authors.lastname: Anderson
mesh_terms: D000818:Animals; D002634:Chemotaxis, Leukocyte / Q000276:immunology*; D005333:Fetus; D005434:Flow Cytometry; D015870:Gene Expression; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000276:immunology*; D007150:Immunohistochemistry; D051379:Mice; D019707:Receptors, Chemokine / Q000096:biosynthesis*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology*; D013950:Thymus Gland / Q000196:embryology* / Q000276:immunology
chemical_list: D019707:Receptors, Chemokine