Specific interaction of Escherichia coli O157:H7-derived Shiga-like toxin II with human renal endothelial cells

In Escherichia coli O157:H7 foodborne infections of humans, the Shiga-like toxins (SLTs) are thought to be the cause of life-threatening vascular complications, including acute renal disease known as hemolytic uremic syndrome or HUS. As virtually all E. coli O157:H7 isolates from HUS patients produce SLT-II (vs. SLT-I), the possible preferential interaction of SLT-II with human renal microvascular endothelial cells (HRMEC), the putative target of the SLTs in the development of HUS, was studied. SLT-II was 1000 times more potent a cytotoxic agent than SLT-I toward HRMEC. Toxin binding studies showed that this occurred although HRMEC could bind 10 times more SLT-I than SLT-II. This preferential action of SLT-II was specific for renal endothelial cells, as human umbilical vein endothelial cells were almost equally affected by SLT-I and SLT-II.