Different cellular cytotoxicity of the various Stx-subtypes probably relates to differences in the toxins’ receptor specificity: Stx1a and Stx2a (associated with hemorrhagic colitis and HUS in humans) bind preferentially to Gb3Cer, whereas Stx2e (associated with edema disease in pigs) prefers Gb4Cer [25,26]. This evidence concerns the gene STX2 and hemolytic-uremic syndrome.