Gal-9 reduces infection of CD4⁺ T cells to HIV-1 infection and up-regulates p21 through interaction with Tim-3. (A) Representative dot plots of activated CD4⁺ T cells in the presence of Gal-9 (1 μg/mL) for 2 hours and also in the presence or absence of anti–Tim-3 antibodies (2.5, 5, and 7.5 μg/mL anti–Tim-3 antibody [clone F38-2E2]) before in vitro infection with X4-Tropic isolate. Data obtained by flow cytometry 5 days after infection. (B) RT-PCR reflecting GAPDH and p21 gene expression in activated CD4⁺ T cells in the absence of Gal-9 (−), presence of Gal-9 (+), and presence of both anti–Tim-3 antibody and Gal-9 (++). SNO2, SN06, and SN011 are 3 HIV-1 seronegative individuals. These data are representative of 3 independent experiments performed on 3 different individuals.