title: Chemokines CCL19 and CCL21 promote activation-induced cell death of antigen-responding T cells.
abstract: Secondary lymphoid organs (SLOs) provide a niche for the initiation and regulation of T-cell responses, but the mechanisms have been poorly understood. We investigated the influence of chemokines CCL19 and CCL21 constitutively expressed in SLOs on activation-induced cell death (AICD) of CD4+ T cells. When paucity of lymph node T cells (plt) mutant mice lacking expression of CCL19/CCL21 were primed with OVA/CFA, both expansion of OVA-responding CD4+ T cells in the draining lymph nodes and an in vitro recall response were prolonged as compared with responses in wild-type (WT) mice. The apoptotic cell frequency among OVA-responding CD4+ T cells was similarly low in plt/plt and WT mice during the clonal expansion phase. However, during the clonal contraction phase, the frequency never increased in plt/plt mice, whereas in WT mice it continuously increased to a peak 18 days after immunization. The presence of CCL19/CCL21 during the in vitro stimulation of CD4+ T cells with anti-CD3 plus anti-CD28 significantly enhanced in vitro AICD induction of the restimulated T cells, partially through enhancing expression of Fas ligand. Our results suggest that CCL19/CCL21 produced by stromal cells and antigen-presenting cells regulate CD4+ T-cell immune responses in SLOs by promoting AICD.
authors.affiliation: Department of Immunology, Toho University School of Medicine, 5-21-16 Omori-nishi, Ota-ku, Tokyo 143-8540, Japan.
authors.forename: Takuwa
authors.initials: T
authors.lastname: Yasuda
authors.forename: Taku
authors.initials: T
authors.lastname: Kuwabara
authors.forename: Hideki
authors.initials: H
authors.lastname: Nakano
authors.forename: Kentaro
authors.initials: K
authors.lastname: Aritomi
authors.forename: Takashi
authors.initials: T
authors.lastname: Onodera
authors.forename: Martin
authors.initials: M
authors.lastname: Lipp
authors.forename: Yousuke
authors.initials: Y
authors.lastname: Takahama
authors.forename: Terutaka
authors.initials: T
authors.lastname: Kakiuchi
mesh_terms: D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D016923:Cell Death / Q000276:immunology; D054415:Chemokine CCL19; D054421:Chemokine CCL21; D019742:Chemokines, CC / Q000276:immunology*; D008221:Lymphoid Tissue / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D012680:Sensitivity and Specificity
chemical_list: C515461:Ccl19 protein, mouse; C515479:Ccl21c protein, mouse; D054415:Chemokine CCL19; D054421:Chemokine CCL21; D019742:Chemokines, CC