CCR7-deficient mice show an age-dependent increase in mucosal CD4⁺ T lymphocytes predominantly of the CD44^hiCD62L^lo CD4⁺ T_EM subtype. Flow cytometric analysis of CD4⁺-gated lymphocytes recovered from the mucosal tissue of the stomach of CCR7^−/− compared with those of wt mice. Numbers indicate the percentages of CD44^loCD62L^hi naive CD4⁺ T cells (top left quadrant), CD44^hi/medCD62L^hi/med CD4⁺ T_CM cells (top right quadrant), or CD44^hiCD62L^lo CD4⁺ T_EM cells (bottom right quadrant). Data are from 2 representative wt and CCR7^−/− mice of 3 to 5 mice per group.