Genetically fused single-chain anti-Salmonella antibody with aequorin: a bioluminescence immunoassay for a Salmonella antigen Original Research Article

We report the development of a competitive heterogeneous immunoassay for BSA-conjugated Salmonella antigen using a fusion protein between an anti-Salmonella single-chain antibody (scFv) and the photo-protein aequorin (AEQ). It has been demonstrated that the fusion protein (scFvLAEQ) maintains both the antibody binding affinity toward the Salmonella antigen as well as the luminescence properties of the photoprotein. Using scFvLAEQ, the competitive immunoassay gave a detection limit of 10 μg ml−1 of Salmonella antigen. The assay eliminates the need for a labeled secondary antibody usually required in enzyme-linked immuosorbent assays (ELISAs), and therefore, it may find potential applications in detecting Salmonella contamination.