New antibody test may detect all known Shiga toxins
According to an article published in AgResearch, certain strains of Escherichia coli produce a toxin called “Shiga toxin,” which can make people ill.
According to an article published in AgResearch, certain strains of Escherichia coli produce a toxin called “Shiga toxin,” which can make people ill. The name for these bacteria is “Shiga toxin-producing E. coli,” or STEC. The most common STEC strain, E. coli O157:H7, is often the cause of the foodborne outbreaks that make news. But many other kinds of E. coli can cause disease. Several commercial tests are available for detecting these bacteria, but none of the tests can recognize all STEC.
Scientists at the U.S. Dept. of Agriculture’s (USDA) Agricultural Research Service (ARS) in Albany, Calif., have developed a highly sensitive test that can detect all known STEC strains. The test, which is an ELISA (enzyme-linked immunosorbent assay), uses novel antibodies developed by molecular biologist Xiaohua He and her team.
The new antibody-based assay identifies all known subtypes of Shiga toxins produced by STEC and has been tested in various studies by He, research leader Luisa Cheng, biologist Larry Stanker, and former ARS postdoctoral research associate Craig Skinner.
Antibodies used in current commercial tests recognize only a subset of Shiga toxins, but not all of them, He explains. The new assay, which uses both monoclonal and polyclonal antibodies, can recognize both Shiga toxin 1 and Shiga toxin 2 and all of their known subtypes. In one study, the newly developed antibodies were able to clear toxins from the blood of mice, protecting them from illness.
The ARS holds patents for these novel antibodies, which have been licensed to Abraxis, TechLab, and List Biological Laboratories.