Comparison of the survival of pre-RTEs (SP4 in adult animals) and naïve T cells in mice.

<p>(A) Purified SP4 thymocytes, and CD4⁺ naïve T cells from lymph nodes of C57BL/6 mice were labeled with CFSE and adoptively transferred into unirradiated adult C57BL/6 mice. Donor T cells from lymph nodes (LN) of the hosts were analyzed for CD44 expression and CFSE dilution (proliferation) 7 days later. The numbers in the plot display the percentage of CD44^hi (upper) and CD44^lo (lower) cells that diluted CFSE. (B) Unlabeled SP4 thymocytes (pre-RTEs) and CFSE-labeled CD4⁺ naïve T cells of CD45.1 congenic mice were mixed at 1:1 ratio and were adoptively transferred into CD45.2 C57BL/6 mice. Seven days later, the mice were sacrificed and cells were harvested from peripheral blood, lymph nodes, peyer’s patch, and spleen. Donor cells collected from host lymph nodes were shown as CD45.1⁺CFSE⁺ (naïve T) and CD45.1⁺CFSE^- (SP4). (C) The ratio of SP4 and naïve T cells (gated as (B)) after seven days of adoptive transfer was calculated. (D) Unlabeled SP4 thymocytes and CFSE-labeled GFP⁺CD4⁺CD8^- lymph node cells (RTEs) from CD45.2 mice were mixed at 1:1 ratio and were transferred into CD45.1 mice. The donor cells were gated at CD45.2⁺CFSE⁺ (RTEs) and CD45.2⁺CFSE^- (SP4) and the ratio was analyzed 7 days later. The experiments were repeated twice and similar results were obtained. Error bars represent SEM. *P<0.05, **P<0.01, using an unpaired Student’s <i>t</i> test. N = 3-4 mice per group.