Ex vivo treatment with IL-7 induces integrin α4β7 in human CD4⁺ and CD8⁺ T cells. (A) Expression of different α and β integrins as evaluated by flow cytometry in PBMCs derived from healthy blood donors after 72 hours of treatment with IL-7 at 5 ng/mL; control cultures (C) were not treated. Data are representative of 3 independent experiments performed with analogous results. The shaded histograms denote staining with the indicated antibody; the empty profiles denote the background fluorescent signal obtained with an irrelevant, isotype-matched antibody. CD4⁺ and CD8⁺ T cells were separately analyzed by differential gating using multicolor flow cytometry. The numbers in each plot indicate the mean fluorescence intensity (MFI) of the stained population. (B) Expression of α4 and β7 in IL-7–treated cells (shaded histogram) or untreated (empty profiles) cells as evaluated by flow cytometry using either subunit-specific antibodies or an antibody that recognizes the heterodimeric α4β7 complex (clone Act1). CD4⁺ and CD8⁺ T cells were purified from the peripheral blood of healthy blood donors and cultured for 72 hours in the presence or absence of IL-7 at 5 ng/mL. Data are representative of 3 independent experiments performed with similar results. (C) Mean levels of expression (± standard error of the mean) of the α4β7 heterodimer in purified CD4⁺ T cells from 25 healthy blood donors treated for 72 hours with IL-7 (5 ng/mL) or left untreated (control). Statistical analysis was performed using a paired 2-tailed t test. (D) Effect of IL-7 on α4β7 expression in NK and B cells. PBMCs derived from a healthy blood donor were treated with IL-7 at 5 ng/mL or left untreated for 72 hours, and the expression of α4β7 was measured by flow cytometry. Data for gated NK cells (CD56⁺) and B cells (CD19⁺) are shown. 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 at least 3 independent experiments performed with similar results. (E) Effect of IL-7 and RA on the expression of integrin α4β7 in purified CD4⁺ T cells. The cells were treated with IL-7 (5 ng/mL) or RA (10μM) or a combination of IL-7 and RA for 72 hours (shaded histograms) or left untreated (empty profiles) in the presence or absence of anti-CD3 + anti-CD28 antibodies. Data are representative of at least 3 independent experiments performed with similar results. (F) Expression of the IL-7 receptor (CD127) in purified CD4⁺ T cells treated with IL-7 or RA (shaded histograms) or left untreated (empty profiles) for 72 hours in the presence or absence of anti-CD3 + anti-CD28 antibodies. Data are representative of 3 independent experiments performed with similar results. (G) Expression of chemokine receptors CCR7, CCR9, and CXCR4 in PBMCs from healthy blood donors after 72 hours of treatment with IL-7 (5 ng/mL); control cultures (C) were not treated. Data are representative of 3 independent experiments performed with analogous results. The shaded histograms denote staining with the indicated antibody; the empty profiles denote the background fluorescent signal obtained with an irrelevant, isotype-matched antibody. The numbers in each plot indicate the MFI of the stained population.