Cutting edge: Central memory CD8 T cells in aged mice are virtual memory cells.
The number of memory phenotype CD8 T cells increases dramatically with aging in both humans and mice. However, the mechanism for this is unknown. The prevailing hypothesis is that memory T cells accumulate with aging as a result of lifelong antigenic stimulation. However, data supporting this supposition are lacking. In this study, we demonstrate that central memory CD8 T cells, which represent a large majority of memory CD8 T cells in aged mice, are not memory cells that develop in response to antigenic stimulation but are virtual memory cells that develop without antigenic stimulation. In addition to phenotypic evidence, we show that accumulation of central memory CD8 T cells is independent of CD4 T cells, CCR5, and CXCR3, all of which are known to be essential for Ag-driven development of central memory CD8 T cells. Thus, this study reveals a novel mechanism for aging-related changes in CD8 T cells.
Department of Pathology, University of Michigan Medical School, Ann Arbor, MI 48109.
Bo-Chin
BC
Chiu
Brian E
BE
Martin
Valerie R
VR
Stolberg
Stephen W
SW
Chensue
D000375:Aging / Q000276:immunology*; D000818:Animals; D000941:Antigens / Q000276:immunology; D015704:CD4 Antigens / Q000502:physiology; D018414:CD8-Positive T-Lymphocytes / Q000737:chemistry / Q000145:classification / Q000276:immunology*; D005260:Female; D018960:Hyaluronan Receptors / Q000032:analysis; D007156:Immunologic Memory / Q000276:immunology*; D019409:Interleukin-15 / Q000276:immunology*; D019041:L-Selectin / Q000032:analysis; D018655:Lymphocyte Count; D038041:Lymphopoiesis; D008297:Male; D051379:Mice; D020297:Mice, Congenic; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D018448:Models, Immunological; D011828:Radiation Chimera; D019713:Receptors, CCR5 / Q000172:deficiency; D054367:Receptors, CXCR3 / Q000172:deficiency; D016176:T-Lymphocyte Subsets / Q000737:chemistry / Q000276:immunology*
D000941:Antigens; D015704:CD4 Antigens; C476399:Cd44 protein, mouse; C515188:Cxcr3 protein, mouse; D018960:Hyaluronan Receptors; D019409:Interleukin-15; D019713:Receptors, CCR5; D054367:Receptors, CXCR3; D019041:L-Selectin