Verotoxin Receptor Glycolipid in Human Renal Tissue

Abstract

Infection with verotoxin producing Escherichia coli has been strongly implicated in the etiology of the hemolytic uremic syndrome (HUS). We have previously shown that this toxin specifically binds to a glycolipid receptor-globotriosyl ceramide (Gb₃). We have therefore quantitated the level of this glycolipid by HPLC in human renal cortex and medulla as a function of age. We have also measured the binding of verotoxin to Gb₃ isolated from each renal tissue sample. Gb₃ was a major component of the glycolipid fraction of all renal samples analyzed. The levels were found to be higher in the cortex than medulla, correlating with the clinical incidence of renal lesions in HUS, but reduced in the kidneys of infants as compared to adults. Verotoxin binding was directly proportional to the renal Gb₃ content. Thus, human renal tissue is a rich source of the verotoxin receptor glycolipid. However, changes in receptor concentration cannot explain the age-related incidence of HUS.