Human cells expressing Neu5Gc are resistant to VcN activity in generating Ctx binding and cell intoxication.

(a-b) DMB-HPLC analysis for sialic acid incorporation in the cell surface glycans of T84 cells fed with 5mM of Neu5Gc (right histogram) or 5mM of Neu5Ac (left histogram) as a control. Arrow indicates the Neu5Gc-corresponding peak in Neu5Gc fed cells that is absent in Neu5Ac fed cells. NT = Not treated. (c) Whole cell ELISA (6 wells for each condition) for Ctx binding to T84 cells with or without VcN treatment. (d) Quantification of cAMP production induced by CtxAB5 with or without VcN treatment calculated for three different wells (biological triplicates) for each condition. Graphs represent one of three independent experiments. Black bars—Neu5Gc fed cells. Gray bars Neu5Ac expressing cells. (*p<0.05 and **p<0.005).