FIG 5.

Sialic acids are required for LtxA-induced lysis of β₂-integrin-expressing K562 cells. (A) Neuraminidase treatment (60 mU ml⁻¹) of LFA-1-transfected K562 cells reduces lysis at increasing concentrations of LtxA. Values are normalized to a control without toxin showing ∼0% lysis. (B) Neuraminidase treatment (60 mU ml⁻¹) of human erythrocytes has no effect on HlyA-induced hemolysis. The erythrocytes and K562 cells were preincubated with neuraminidase for 60 min and afterwards incubated for 60 and 90 min with the toxin, respectively. All experiments were conducted at 37°C with shaking (250 rpm). Data are shown as mean ± SEM (n = 3 to 7). *, statistical difference from the control (P < 0.05).