Figure 7.

CD11b⁺ leukocytes carry and deliver Stx2 to Vero cells. Vero cells labeled with CSFE were cultured in a 96-well plate (~1 × 10⁵ cells/well) for 12 h. Excessive dye was washed off prior to the culture. Cell viability after the treatment was determined by counting cells under a fluorescent microscope. (A) Plasma toxicity study. Plasma were obtained from healthy control mice, LPS-primed mice (300 μg/kg, i.p; 48 h after the injection) or HUS-developed mice (4 h after 2^nd Stx2 i.p. injection, as described in manuscript), followed by the incubation with Vero cells (100 μl each well, 37 °C, 24 h). (B) Stx2 delivery study. CD11b⁺ cells isolated from the peripheral blood of LPS-primed or unprimed mice were incubated with a series of concentrations of Stx2 (0, 2, 20, 200 and 2000 ng/ml, respectively; 25 °C, 30 min). After thoroughly washing, Stx2-treated CD11b⁺ cells were incubated with Vero cells (1 × 10⁵ CD11b⁺ cells each well, 37 °C, 24 h). Data represent three independent experiments; n = 4; *P < 0.05, **P < 0.01, ***P < 0.001 versus respective controls.