title: Age-associated parallel increase of Foxp3(+)CD4(+) regulatory and CD44(+)CD4(+) memory T cells in SJL/J mice.
abstract: Effector/memory T cells (Tem) are required to maintain successful immunity, while regulatory T cells (Treg) are required to prevent excessive/uncontrolled inflammation and/or autoimmunity. Although both Tem and Treg cells are increased during aging, the relationship between the increased proportion of Foxp3(+) Treg cells and CD44(+) Tem cells with aging is not clearly understood. We found in this report that Foxp3(+) Treg cells are increased in parallel with CD44(+) Tem cells in SJL/J mice with aging, and that all Foxp3(+) Treg cells are of CD44(+) Tem phenotype, suggesting that the increased Foxp3(+) Treg cells originated from the expanded pool of CD44(+) Tem cells with aging. Our in vitro kinetic studies further suggested that Foxp3(+) Treg cells are converted through the CD44(+) stage. Furthermore, we observed that although the balance between Foxp3(+) Treg and CD44(+)Foxp3(-) Tem cells remained with aging, the aged mice have higher ratios of both Tem and Treg cells vs. naïve T cells resulting in the "shrunken" naïve T cell pools. Our results suggest that an age-associated imbalance of T cell repertoire is a mechanism that contributes to spontaneous occurrence of Hodgkin's-like lymphoma in aged SJL/J mice.
authors.affiliation: Department of Comparative Biomedical Sciences, Louisiana State University, Baton Rouge, 70803, USA.
authors.forename: Guang-Ming
authors.initials: GM
authors.lastname: Han
authors.forename: Baohua
authors.initials: B
authors.lastname: Zhao
authors.forename: Samithamby
authors.initials: S
authors.lastname: Jeyaseelan
authors.forename: Ji-Ming
authors.initials: JM
authors.lastname: Feng
mesh_terms: D000375:Aging / Q000276:immunology*; D000818:Animals; D004198:Disease Susceptibility / Q000276:immunology; D051858:Forkhead Transcription Factors / Q000276:immunology; D006689:Hodgkin Disease / Q000276:immunology; D018960:Hyaluronan Receptors / Q000276:immunology; D007156:Immunologic Memory; D008198:Lymph Nodes / Q000276:immunology; D018655:Lymphocyte Count; D051379:Mice; D013154:Spleen / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*
chemical_list: C476399:Cd44 protein, mouse; D051858:Forkhead Transcription Factors; C498833:Foxp3 protein, mouse; D018960:Hyaluronan Receptors