title: Double-sandwich enzyme-linked immunosorbent assay for determination of Escherichia coli heat-labile porcine enterotoxins.
abstract: A "double-sandwich" ELISA for the detection and measurement of a heat-labile enterotoxin produced by porcine enterotoxigenic strains of Escherichia coli (LTp) is described. In contrast with other heat-labile toxins, LTp did not bind to agarose gels and exhibited a very low affinity for GM1 in the classical GM1-ELISA technique. The similarity of LTp with cholera toxin was confirmed by immunoblotting. This property allowed the binding of LTp to rabbit IgG anti-cholera toxin antibodies (covalently linked to polystyrene plates) and sheep anti-cholera toxin serum. The immunocomplex was revealed by anti-sheep immunoglobulin antibodies conjugated with peroxidase. Application of the "double-sandwich" ELISA to the quantitation of toxin production by two strains, which differ only in the presence or the absence of the K88ab antigen, showed that the Ent+, K88+ strain produced significantly less toxin than the Ent+, K88- derivative.
mesh_terms: D000818:Animals; D001427:Bacterial Toxins / Q000032:analysis*; D002772:Cholera Toxin / Q000032:analysis / Q000276:immunology; D004768:Enterotoxins / Q000032:analysis*; D004797:Enzyme-Linked Immunosorbent Assay; D004926:Escherichia coli; D029968:Escherichia coli Proteins; D015151:Immunoblotting; D013552:Swine
chemical_list: D001427:Bacterial Toxins; D004768:Enterotoxins; D029968:Escherichia coli Proteins; D002772:Cholera Toxin; C027538:heat-labile enterotoxin, E coli