Induction of α4β7 by IL-7 occurs primarily in naive T cells. Purified CD4⁺ and CD8⁺ T cells were cultured in the presence or absence of IL-7 at 5 ng/mL. After 24 hours of culture, the expression of α4β7 was evaluated in the naive (CD45RA⁺CD45RO⁻CCR7⁺CD62L⁺), central memory (CM; CD45RA⁻CD45RO⁺CCR7⁺CD62L⁺) and effector memory (EM; CD45RA⁻CD45RO⁺CCR7⁻CD62L^±) cell subsets by flow cytometry. The shaded histograms denote the staining of IL-7–treated cells; the empty profiles denote the staining of control, untreated cells. Data are representative of 3 independent experiments performed with similar results.