Figure 3. T_Mem cells cause precocious differentiation of T_N cells in vivo.

(A) Experimental schema showing the generation, isolation, and transfer of Thy1.1⁺ pmel-1 T_N cells (CD44^loCD62L⁺) alone or in combination with FACS-sorted, vaccine-induced Ly5.1⁺ pmel-1 T_Mem cells (CD44^hi) into Ly5.2⁺ hosts. (B) In vivo expansion and persistence of 1 × 10⁵ adoptively transferred Thy1.1⁺ T_N cells injected alone or in combination with 3 × 10⁵ Ly5.1⁺ T_Mem cells into Ly5.2⁺ WT mice bearing 10-day established B16 melanomas. (C) FACS analysis on day 17 of CD27 and KLRG1 expression on CD8⁺Thy1.1⁺ T_N-derived or CD8⁺Ly5.1⁺ T_Mem-derived cells. (D) Tumor regression and survival of mice bearing 10-day established B16 melanoma tumors who received 1 × 10⁵ T_N cells alone, in combination with 3 × 10⁵ T_Mem cells, or 3 × 10⁵ T_Mem cells alone. All treated mice received 6 Gy irradiation, i.v. rVV-gp100, and 3 days of i.p. IL-2. n = 3 mice/group/time point (B and C) or n = 5 mice per group (D). Results are displayed as mean ± SEM with statistical comparisons performed using an unpaired 2-tailed Student’s t test corrected for multiple comparisons by a Bonferroni adjustment or log-rank test for animal survival. *P < 0.05; **P < 0.01. Data shown are representative of 2 independently performed experiments.