Production, characterization and immunodiagnostic application of a monoclonal antibody to Shiga toxin.

A mouse monoclonal antibody (MAb ICT7) that is specific for Shiga toxin was produced. The MAb neutralises the cytotoxic effects of both purified Shiga toxin and culture extracts of Shigella dysenteriae type 1 in HeLa cells. Using MAb ICT7 and polyclonal rabbit antiserum, a sandwich ELISA was developed. This test detects Shiga toxin in both S. dysenteriae type 1 bacterial extracts and in stools of patients with S. dysenteriae type 1 infection. The ELISA also detects toxin in enterohaemorrhagic Escherichia coli (EHEC) strains positive for Shiga-like toxin I. The test could detect a minimum of 100 pg of purified Shiga toxin. Furthermore, the ELISA did not detect toxin in non-S. dysenteriae type 1 Shigella species or Shiga-like toxin II produced by EHEC strains.