EVIDENCE THAT VEROTOXINS (SHIGA-LIKE TOXINS) FROM ESCHERICHIA-COLI BIND TO P-BLOOD-GROUP ANTIGENS OF HUMAN ERYTHROCYTES IN-VITRO

The interaction of verotoxins (VTs) with human erythrocytes (RBCs) in vitro was investigated, with particular reference to the role of P blo od group glycolipids that are structurally related to the known VT rec eptors. RBC binding of purified VT1, VT2, VT2c, and VT2e was detected by direct and indirect immunofluorescence. Glycolipids were extracted from defined RBCs, separated by thin-layer chromatography, and assesse d for VT binding in an overlay assay by adding toxin and specific anti bodies. All VTs bound to P1 phenotype (Pk, P, and P1 antigens) and P2 phenotype (Ph and P antigens) RBCs but not to p phenotype (lacking the Pk, P, and P1 antigens) RBCs. Binding of VT1 and VT2 was approximatel y 10-fold greater to P1 and the rare Pk2 (Pk antigen but no P1 or P an tigen) phenotype cells than to P2 phenotype RBCs, whereas VT2e bound e qually well to P1 and P2 phenotype cells. The VT1 and VT2 immunofluore scence results correlated with the detection of P1 and/or increased am ounts of Pk (globotriaosylceramide) antigen; VT2e immunofluorescence c orrelated with the detection of P (globotetraosylceramide) antigen. Th e Pk band pattern and VT binding observed in the thin-layer chromatogr am of human P1 and P phenotype RBC extracts varied from that of human kidney and Pk1 phenotype (Pk and P1 antigens) RBCs. We conclude that e ach VT binds tb human RBCs in vitro by utilizing specific P blood grou p glycolipids as receptors. On P1 and P phenotype RBCs, the accessibil ity of the Pk antigen for VTs appeared to be restricted. The occurrenc e of VT-RBC binding in natural VT-producing Escherichia coli disease a nd its relevance for the pathophysiology of hemolytic uremic syndrome remain to be established.