title: Antigen-independent generation of a unique CD4 T cell-subset with aging and its persistent unresponsiveness.
abstract: Aging leads to a decline in the reactivity of CD4 T cells, in humans and mice. However, we have reported that not all CD4 T cells in aged mice were hyporesponsive, that is, a particular subset maintained the ability to mount a normal response. In this study, we examined the possibility of recalling reactivity in the hyporesponsive CD4 T cell-subset in aged mice. In vivo experiments revealed the changes in CD4 T cell-subsets in aged mice to be antigen-independent and aging-dependent. Once the CD4 T cells became hyporesponsive, they persistently exhibited a weak response. Furthermore, immunization with a co-stimulatory antibody had no effect on T cell-responses in aged mice, although it had a significant effect in young mice. As this hyporesponsive subset accounts for the majority of CD4 T cells in aged mice, it is important to elucidate the cause of the hyporesponsiveness.
authors: Center for Innovation in Immunoregulative Technology and Therapeutics, Graduate School of Medicine, Kyoto University, Yoshidakonoe-cho, Sakyo-ku, Kyoto 606-8501, Japan.
authors: Emi
authors: E
authors: Nishida
authors: Tomohisa
authors: T
authors: Nishioka
authors: Ryuji
authors: R
authors: Iida
authors: Hideo
authors: H
authors: Yagita
authors: Akimichi
authors: A
authors: Morita
authors: Jun
authors: J
authors: Shimizu
mesh_terms: D000375:Aging / Q000276:immunology*; D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D007108:Immune Tolerance / Q000276:immunology*; D007114:Immunization; D008213:Lymphocyte Activation / Q000276:immunology*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D010047:Ovalbumin / Q000276:immunology; D016176:T-Lymphocyte Subsets / Q000276:immunology* / Q000378:metabolism
chemical_list: D010047:Ovalbumin