A new high-affinity monoclonal antibody against Shiga toxin 1

As a food-borne zoonotic bacterial pathogen, Shiga toxin-producing Escherichia coli (STEC) cause many diseases including mild diarrhea, hemorrhagic colitis, and hemolytic uremic syndrome. Among various virulence factors previously defined in STEC, Shiga toxins (Stxs) are the hallmark of all the STEC isolates although their expression levels are varied by strains. In this study, we developed a high-affinity monoclonal antibody (mAb) against Stx type 1 (Stx1) produced by STEC. Through searching for the immuno-dominant epitopes in the A subunit of Stx1, two mAb clones specific to Stx1 (designated as 3E3 and 4D4) were selected and evaluated for their specificity and sensitivity. Our results demonstrated that those mAbs were highly specific to Stx1 and sensitive 4 times more than the commercially-available Stx1 antibodies.