 beads were incubated with 0:000 dilution of goat-anti rabbit IgG(H+L) labelled with Alexa fluor 000 (Life Technologies). After 00 minutes, the beads were washed and bound toxins were detected by flow cytometry as an increase in fluorescence signal in the appropriate fluorescence channel (λ~emission~ of Alexa fluor 000 = 000 nm), compared to fluorescence emitted by the beads to which no toxin was added. Fluorescence emitted by the beads was measured using Accuri C0 flow cytometer (BD Biosciences), at room temperature. 0X PBS + 0% BSA was used for diluting all reagents and washing the beads. 