TGF-β suppresses the differentiation of transitional subsets of CD8 ⁺ T cells. (A) Same experimental setup as in Fig. 1. Day 21–23 after infection, representative FACS profiles of pre-gated donor P14 T cells isolated from the spleen (three independent repeats). (B–G) Characterization of the four P14 subsets defined by the expression of Tcf-1 and CD69. The percentage of each subset in total P14 T cells (B), intravascular anti-CD8α labeling in each subset (C and D), and the percentage of β1⁺β7⁺ cells in each subset (E) are shown. (F) Representative FACS profiles to show the expression of CX3CR1 and Granzyme A in each subset of P14 T cells. (G) The percentage of CX3CR1⁺ cells in each subset is shown. Each pair of symbols in B, D, E, and G represents the results from an individual recipient mouse. Pooled or representative results from two (C–E, n = 10; F and G, n = 4) or three (A and B, n = 14) independent experiments are shown. *, P < 0.05; **, P < 0.01; ***, P < 0.001; and ****, P < 0.0001 by ordinary one-way ANOVA or Student’s t test.