T_(TN) cells engraft, expand, and exhibit xenoreactivity and self-renewing ability on transfer into immunodeficient mice. NOD/Scid mice were conditioned, infused IP with 5 × 10⁶ human T lymphocytes, and followed for human chimerism and incidence of severe GVHD. (A) Flow cytometric analysis of human chimerism on peripheral blood (PB) at week 2 after infusion. (B) Mice were followed for severe GVHD-free survival over time (defined as weight loss greater than 5% concomitant to human chimerism greater than 10%). (C) Expression of CD45RA and CD62L on circulating human CD8⁺ T cells 2 weeks after infusion. FACS plots from representative T_(TN)– and T_(TCM)–infused mice (left) and average histograms (right) are shown. (D) Expression of IL-7Rα on circulating human CD8⁺ T cells from T_(TN)– and T_(TCM)–infused mice: representative plot (left) and average histograms (right). Gray histograms represent fluorochrome-matched isotype controls. (E) Percentages of human T cells retrieved from spleen and BM of T_(TN)– and T_(TCM)–infused mice at sacrifice. (F) Absolute numbers of human T cells retrieved per spleen of T_(TN)– and T_(TCM)–infused mice at sacrifice. The dashed line indicates the number of cells infused. (G) Results of serial transplantation experiments; 5 × 10⁶ BM- and spleen-retrieved human T cells from first transplantation were infused into secondary recipients and human chimerism on PB was assessed 1 week after infusion. (H) GVHD-free survival in secondary recipients. (I) Representative plots of CD45RA/CD62L phenotype (left) and IL-7Rα (right) on circulating CD8⁺ T cells from T_(TN) secondary recipients. (J) Human chimerism on BM and spleen at sacrifice.