Memory CD8 T cells do not retain α4β7 expression regardless of anatomical location or immunization route. (A and B) Expression of α4β7 and/or CCR9 by P14 isolated from various tissues 4.5, 7, or 60 d after i.p. LCMV infection (A) or by OT-I after oral LMova infection (B). All plots are gated on Thy1.1⁺ CD8⁺ lymphocytes. (C) 10⁶ Thy1.1⁺ P14 isolated from spleen (red), iLN (blue), or mLN (green) 4.5 d after LCMV infection was transferred to naive mice. The next day, lymphocytes were harvested from recipient spleen and small intestinal epithelium, and the proportion of CD8⁺ lymphocytes that were Thy1.1⁺ was determined. Only p-values of <0.05 are shown. (D) Recipient mice received the entire single cell suspension derived from either one spleen or the complete cluster of mLN derived from one mouse isolated 4.5 d after LCMV infection. The next day, the proportion of CD8⁺ lymphocytes that were Thy1.1⁺ was determined. Error bars indicate SEM. All data are representative of at least two experiments with at least three mice per group in each experiment.