Integrin α4 blocking rescues the defective maintenance of Tcf-1 ⁺ Tgfbr2 ^−/− in vivo without directly interfering with Tcf-1 ⁺ cell differentiation in vitro. Same experimental setup as in Fig. 5. (A) The percentage of Tcf-1⁺ cells in donor P14 T cells isolated from the lymph nodes are shown. (B) MFI of α4β7 on Tcf-1⁺ and Tcf-1⁻ donor P14s are shown. Each pair of symbols represents the results from an individual recipient. Pooled results from five independent experiments are shown in A (n = 15–20). Representative results from two independent experiments are shown in B (n = 5). (C) Experimental design for in vitro integrin α4 blocking. (D) Representative FACS profiles of pre-gated live P14 T cells after 4-d culture are shown. Representative results from two independent experiments (P14 T cells were pooled from five mice/each experiment as sorting input cells) are shown in D. **, P < 0.01; ***, P < 0.001; and ****, P < 0.0001 calculated by paired Student’s t test.