title: Aging-dependent generation of suppressive CD4+CD25-R123loCD103+ T cells in mice.
abstract: Advancing age is associated with significant alterations in immune functions, including a decline in CD4 T cell function, in both mice and humans. In our previous report, we showed that CD4(+)CD25(-) T cells in aged (24-month-old) mice, especially after in vitro pre-stimulation of these cells, exhibit hyporesponsive and suppressive properties. We examined here whether the suppressive activity of aged CD4(+)CD25(-) T cells is ascribable to a particular population within these cells. In vitro analyses revealed that cell populations rapidly extruding Rhodamine-123 (R123) (referred to as R123(lo) cells) in aged CD4(+)CD25(-) T cells have a more potent suppressive function compared with R123(hi) populations. In addition, CD103(+) cells in freshly prepared aged CD4(+)CD25(-)R123(lo) T cells had a most potent suppressive activity. Both R123(hi) and R123(lo) populations had individually stronger suppressive activity after pre-stimulation than before pre-stimulation. Furthermore, the R123(lo) population in young CD4(+)CD25(-) T cells also had different properties from R123(hi) T cells: low responsiveness, no additive effect in proliferation assays, and the gain of a suppressive function after in vitro pre-stimulation. Taken together, these results suggest that CD4(+)CD25(-)R123(lo) T cells are a unique population within whole CD4(+)CD25(-) T cells. This population exists in the early stage of the life span, and the properties in this population become obvious with aging, that is the gain of their suppressive activity.
authors.affiliation: Immunological Aging Research Group, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan. jun@tmig.or.jp
authors.forename: Jun
authors.initials: J
authors.lastname: Shimizu
authors.forename: Eiko
authors.initials: E
authors.lastname: Moriizumi
mesh_terms: D000375:Aging / Q000276:immunology*; D000818:Animals; D015703:Antigens, CD / Q000378:metabolism*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D039001:Integrin alpha Chains / Q000378:metabolism*; D051379:Mice; D015375:Receptors, Interleukin-2 / Q000378:metabolism*; D020112:Rhodamine 123 / Q000378:metabolism*
chemical_list: D015703:Antigens, CD; D039001:Integrin alpha Chains; D015375:Receptors, Interleukin-2; C091367:alpha E integrins; D020112:Rhodamine 123