Investigation of Shiga-like Toxin Binding to Chemically Synthesized Oligosaccharide Sequences

Abstract

Shiga-like toxin (SLT)-1 and SLT-II/lIc bound to Synsorbs containing synthetic αGal(1–4)βGal (P1 disaccharide), αGal(1–4)βGal(1–4)βGlcNAc (PI trisaccharide), or αGal(1–4)βGal(1–4)βGlc (Pk trisaccharide) sequences but not to Synsorbs containing αGal(1–3)βGal, αGal(1–3) αGal(1–4)βGlcNAc, or the hydrophobic oligosaccharide linkage arm. SLT-I had a preference for Synsorbs containing trisaccharides, whereas SLT-II/IIe binding was less selective. ¹²⁵I-labeled SLT-I remained bound to Pk trisaccharide Synsorb in the presence of lactose, galactose, or EDTA but was partially released by acetic acid, guanidine HCl, or a 10% solution ofSDS. Vero cells coincubated with Pk trisaccharide Synsorb and SLT 1 extract were protected from this toxin, whereas Pk trisaccharide Synsorb was much less efficient at neutralizing SLT-II/IIe activity in Vero cell coincubation experiments. The SLT-lIe component was not responsible for the inefficient neutralization. Results suggest that synthetic oligosaccharide sequences related to the P blood group antigens coupled to inert matrices could be useful for rapid diagnosis or possibly therapeutic intervention in enterohemorrhagic Escherichia coli infections.