Reevaluation of the origin of CD44(high) "memory phenotype" CD8 T cells: comparison between memory CD8 T cells and thymus-independent CD8 T cells.
CD44(high)CD8 T cells in naive mice, which increase with age, and are often referred to as memory CD8 T cells. However, since thymus-independent CD8 T cells have also been shown to be CD44(high), the origin of the CD44(high)CD8 T cells in naive mice remains unclear. In this study, we compared the characteristics of memory CD8 T cells and thymus-independent CD8 T cells in TCR transgenic mice to clarify the origin of the CD44(high)CD8 T cells in naive normal mice. The memory and thymus-independent CD8 T cells showed differences in surface molecules, spontaneous cell death, cytokine production, and response to IL-2R binding of cytokines. Importantly, the "memory phenotype" CD8 T cells in naive normal mice showed similar characteristics to the thymus-independent CD8 T cells, but differed greatly from "true" memory CD8 T cells in the TCR transgenic mice. Therefore, we conclude that a significant part of the CD44(high) memory phenotype CD8 T cells in naive normal mice represents thymus-independent CD8 T cells, which may participate in age-related changes in immune responses.
Yamada
H
H
Department of Orthopedic Surgery, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan. hisaky@hotmail.com
Matsuzaki
G
G
Chen
Q
Q
Iwamoto
Y
Y
Nomoto
K
K
D000818:Animals; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D016923:Cell Death; D002455:Cell Division; D005260:Female; D006182:H-Y Antigen / Q000276:immunology; D006801:Humans; D018960:Hyaluronan Receptors / Q000096:biosynthesis / Q000276:immunology*; D007156:Immunologic Memory / Q000276:immunology*; D016130:Immunophenotyping; D007371:Interferon-gamma / Q000096:biosynthesis; D007376:Interleukin-2 / Q000096:biosynthesis; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D011946:Receptors, Antigen / Q000235:genetics / Q000276:immunology; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000276:immunology; D015375:Receptors, Interleukin-2 / Q000096:biosynthesis / Q000276:immunology; D013950:Thymus Gland / Q000166:cytology / Q000276:immunology*
D006182:H-Y Antigen; C028507:H-Y antigen receptor; D018960:Hyaluronan Receptors; D007376:Interleukin-2; D011946:Receptors, Antigen; D016693:Receptors, Antigen, T-Cell, alpha-beta; D015375:Receptors, Interleukin-2; D007371:Interferon-gamma