CD4 and HIV-1 infection: Previous studies indicated that galectin-1 promotes HIV-1 infection through stabilization of viral attachment to macrophages [10] and CD4+ T cells [11], and galectin-9 inhibits HIV-1 infection via resistance of activated CD4+ T cells to HIV-1 infection and triggering Tim-3 downstream signaling via Gal9/Tim-3 interaction [21].