Only early effector CD8 T cells migrate to intestinal epithelium and express α4β7. (A) Dynamics of P14 response to LCMV. The day 37 time point represents 12 mice analyzed from days 31 to 50 after infection. (B) Experimental design consists of transferring P14 at different stages of differentiation and harvesting tissues the next day. (C) Numbers of naive (N), effector (isolated 4.5 or 7 d after infection), and memory (isolated 60 d after infection) cells isolated from recipient spleen and intestinal epithelium (IEL). ns, not significant, *, P < 0.05; **, P < 0.01, unpaired Student’s t test. Error bars indicate SEM. (D) Virus-specific P14 CD8 T cells were analyzed for expression of α4β7. gmfi, geometric mean fluorescence intensity of α4β7 staining. All plots are gated on Thy1.1⁺ CD8⁺ lymphocytes and are representative of at least three independent experiments totaling >10 mice/time point.