Bovine arterial endothelial cells showed lower sensitivity to Stx in vitro than porcine cells. The bovine glomerulus lacks a receptor for Stx, grobotriaosylceramide (Gb3), which exists in the porcine glomerulus. These findings may explain why Escherichia coli O157:H7 does not provoke systemic disorders in cattle. (Comparative Pathology Section, Kyushu Research Station TEL +81-99-268-2078)