title: Role for CCR7 ligands in the emigration of newly generated T lymphocytes from the neonatal thymus.
abstract: Most T lymphocytes are generated within the thymus. It is unclear, however, how newly generated T cells relocate out of the thymus to the circulation. The present study shows that a CC chemokine CCL19 attracts mature T cells out of the fetal thymus organ culture. Another CC chemokine CCL21, which shares CCR7 with CCL19 but has a unique C-terminal extension containing positively charged amino acids, failed to show involvement in thymic emigration. Neonatal appearance of circulating T cells was defective in CCL19-neutralized mice as well as in CCR7-deficient mice but not in CCL21-neutralized mice. In the thymus, CCL19 is predominantly localized in the medulla including endothelial venules. These results indicate a CCL19- and CCR7-dependent pathway of thymic emigration, which represents a major pathway of neonatal T cell export.
authors.affiliation: Division of Experimental Immunology, Institute for Genome Research, The University of Tokushima and Laboratory of Immune System Development, RIKEN Research Center for Allergy and Immunology, 3-18-15 Kuramoto, 770-8503, Tokushima, Japan.
authors.forename: Tomoo
authors.initials: T
authors.lastname: Ueno
authors.forename: Kyoko
authors.initials: K
authors.lastname: Hara
authors.forename: Melissa Swope
authors.initials: MS
authors.lastname: Willis
authors.forename: Mark A
authors.initials: MA
authors.lastname: Malin
authors.forename: Uta E
authors.initials: UE
authors.lastname: Höpken
authors.forename: Daniel H D
authors.initials: DH
authors.lastname: Gray
authors.forename: Kouji
authors.initials: K
authors.lastname: Matsushima
authors.forename: Martin
authors.initials: M
authors.lastname: Lipp
authors.forename: Timothy A
authors.initials: TA
authors.lastname: Springer
authors.forename: Richard L
authors.initials: RL
authors.lastname: Boyd
authors.forename: Osamu
authors.initials: O
authors.lastname: Yoshie
authors.forename: Yousuke
authors.initials: Y
authors.lastname: Takahama
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D054415:Chemokine CCL19; D054421:Chemokine CCL21; D019742:Chemokines, CC / Q000235:genetics / Q000502:physiology*; D002633:Chemotaxis / Q000502:physiology*; D015870:Gene Expression; D006801:Humans; D008024:Ligands; D051379:Mice; D018345:Mice, Knockout; D009500:Neutralization Tests; D009924:Organ Culture Techniques; D054400:Receptors, CCR7; D019707:Receptors, Chemokine / Q000235:genetics / Q000502:physiology*; D013601:T-Lymphocytes / Q000166:cytology / Q000502:physiology*; D013950:Thymus Gland / Q000166:cytology* / Q000196:embryology
chemical_list: C515460:CCL19 protein, human; C515478:CCL21 protein, human; C515370:CCR7 protein, human; C515461:Ccl19 protein, mouse; C515479:Ccl21c protein, mouse; C515371:Ccr7 protein, mouse; D054415:Chemokine CCL19; D054421:Chemokine CCL21; D019742:Chemokines, CC; D008024:Ligands; D054400:Receptors, CCR7; D019707:Receptors, Chemokine