Gal-9 down-regulates CCR5, CXCR4 and α4β7 on the surface of activated CD4⁺ T cells. (A) Percentage of CCR5 suppression in PHA activated CD4⁺ T cells after stimulation with Gal-9 (1 μg/mL) for 2 and 12 hours. Data obtained from 8 HIV-1 seronegative individuals. (B) Percentage of CXCR4 suppression in IL-4/dexamethasone activated CD4⁺ T cells after stimulation with Gal-9 (1 μg/mL) for 2 and 12 hours. Data obtained from 4 HIV-1 seronegative individuals. (C) Percentage of α4β7 suppression in retinoic acid activated CD4⁺ T cells after stimulation with Gal-9 (1 μg/mL) for 2 and 12 hours. Data obtained from 9 HIV-1 seronegative individuals. Significance was tested using paired t test. (D-F) Representative flow cytometry dot plots from CD4⁺ T cells in the absence of Gal-9 (−Gal-9; left flow panel) or in the presence of Gal-9 (+Gal-9; right flow panel) for CCR5, CXCR4, and α4β7, respectively. Data obtained 2 hours after stimulation with Gal-9. Error bars indicate mean ± SEM from duplicate cell cultures from 4 to 9 independent experiments performed in vitro. Each point represents an individual.