PT  - JOURNAL ARTICLE
AU  - Thome, Joseph J. C.
AU  - Grinshpun, Boris
AU  - Kumar, Brahma V.
AU  - Kubota, Masaru
AU  - Ohmura, Yoshiaki
AU  - Lerner, Harvey
AU  - Sempowski, Gregory D.
AU  - Shen, Yufeng
AU  - Farber, Donna L.
TI  - Long-term maintenance of human naïve T cells through in situ homeostasis in lymphoid tissue sites
AID  - 10.1126/sciimmunol.aah6506
DP  - 2016 Dec 02
TA  - Science Immunology
PG  - eaah6506
VI  - 1
IP  - 6
4099  - http://immunology.sciencemag.org/content/1/6/eaah6506.short
4100  - http://immunology.sciencemag.org/content/1/6/eaah6506.full
SO  - Sci. Immunol.2016 Dec 02; 1
AB  - Naïve T cells develop in the thymus. Although thymic function declines with age, T cells are persistent throughout the human life span. Thome et al. examined human lymphoid tissues from donors ranging from 2 months to 73 years in age. They found that, although the number of double-positive thymocytes and recent thymic emigrants dropped in individuals >40 years of age, naïve T cells were functionally maintained in the lymph nodes. There was minimal overlap in clonotype between the lymph tissues, suggesting that lymph nodes may maintain a diverse set of T cell specificities. These data suggest that location really does matter—tissue compartmentalization and homeostasis are critical for maintaining naïve T cells throughout the human life span.Naïve T cells develop in the thymus and coordinate immune responses to new antigens; however, mechanisms for their long-term persistence over the human life span remain undefined. We investigated human naïve T cell development and maintenance in primary and secondary lymphoid tissues obtained from individual organ donors aged 2 months to 73 years. In the thymus, the frequency of double-positive thymocytes declined sharply in donors >40 years of age, coincident with reduced recent thymic emigrants in lymphoid tissues, whereas naïve T cells were functionally maintained predominantly in lymph nodes (LNs). Analysis of T cell receptor clonal distribution by CDR3 sequencing of naïve CD4+ and CD8+ T cells in spleen and LNs reveals site-specific clonal expansions of naïve T cells from individuals >40 years of age, with minimal clonal overlap between lymphoid tissues. We also identified biased naïve T cell clonal distribution within specific LNs on the basis of VJ usage. Together, these results suggest prolonged maintenance of naïve T cells through in situ homeostasis and retention in lymphoid tissue.