Development of an Antidote for E Coli 0157--H7 Verotoxin

E. coli Ol57:H7 is an emerging food-borne pathogen with substantial morbidity and mortality.There are an estimated 20,000 cases of E. coli 0157:H7 infection per year in the United States.However, only 11 states require reporting of the cases to the State Health Department; hence, the actualnumber of cases is likely to be much higher. Twenty-two percent of children acquiring E. coli Ol57:H7infection develop potentially fatal complications, such as hemolytic uremic syndrome (HUS). Patientswho develop complications must be hospitalized for long periods, and often require life-long kidneydialysis or kidney transplants. HUS is believed to be caused by verotoxins produced by the offendingbacterium, and there are no antitoxins available for clinical use. We will develop E. coli Ol57:H7antiverotoxin using proprietary methods for the large-scale production of therapeutic polyclonalantibodies from eggs of hyperimmune hens. High-purity avian antitoxins have been shown to havesuperior toxin-neutralizing potency when used in either a parenteral or enteral dosing regimen. Hens willbe immunized with pure E. coli O157:H7 verotoxins, followed by preparation of yolk immunoglobulinfractions. The resulting antibodies will be characterized in vitro by immunochemical analysis and bytoxin neutralization in a vero cell assay. The therapeutic efficacy of antiverotoxin will be assessed invivo in a mouse HUS model using either enteral or parenteral antiverotoxin administration. These studieswill i) provide experimental evidence for the therapeutic utility of antiverotoxin antibodies in E. coliO157:H7 disease, such as HUS, and ii) determine if disease progression can be arrested by antiverotoxinenterally administered and/or whether antiverotoxin is effective when given parenterally.