Immunological detection assays for recombinant Shiga toxin & Shigella dysenteriae

BACKGROUND & OBJECTIVES: Shiga toxin (Stx) is produced by Shigella dysenteriae, a Gram-negative, facultative anaerobic bacillus that causes shigellosis, haemolytic uraemic syndrome (HUS) and Reiter's syndrome. The detection methods for shiga toxin needs to be rapid, accurate, reliable and must be extensively evaluated under field conditions. The aim of this study was to develop rapid, sensitive and specific detection method for Stx. METHODS: Mice and rabbits were immunized with purified recombinant Shiga toxin B (rStxB). Using these antibodies dot ELISA, sandwich ELISA and flow through assay were developed. RESULTS: The high-titre antibodies specifically reacted with purified rStxB. Dot-ELISA, sandwich ELISA and flow-through assay were developed and standardized that could detect StxB with limit of detection (LOD) of 9.75, 9.7 ng/ml and 0.46 μg/cassette, respectively. INTERPRETATION & CONCLUSIONS: The rStxB was used to produce antibodies to avoid handling of pathogen. The Flow through assay ‘developed was specific, rapid and field amenable.