Engineering an anti-Stx2 antibody to control severe infections of EHEC O157:H7

Enterohaemorrhagic Escherichia coli (EHEC) O157:H7, a primary enteric pathogen, has been implicated in a wide spectrum of food/water-borne infectious diseases such as hemorrhagic colitis (HC) and hemolyticuremic syndrome (HUS). Effective treatments for EHEC O157:H7 induced disease are not available yet. Shiga-toxin 2 (Stx2) has been related to clinical manifestations of HUS, suggesting its critical role in pathology following infection with EHEC O157:H7. Here we report the development of four anti-Stx2-Monoclonal antibodies (McAbs) (5F3and 5C11 for Stx2A, and 1A4 and 1A5 for Stx2B), all of which have strong immunogenicity and neutralization activities in vitro and in vivo. The full-length cDNA coding for anti-Stx2A McAb, 5F3, was cloned and an engineered antibody was developed whose therapeutic effects were evaluated. Our data indicate that the engineered scFv together with two new McAbs may be applicable for the prevention and therapy of EHEC induced pathology.