Development of an immunoassay using recombinant maltose-binding protein-STa fusions for quantitating antibody responses against STa, the heat-stable enterotoxin of Escherichia coli.

A set of fusion proteins containing heat-stable enterotoxin (STa) and maltose-binding protein were engineered. These molecules were readily purified and used as solid-phase antigens in an enzyme-linked immunosorbent assay to monitor anti-STa responses in mice immunized with a recombinant vaccine composed of STa and the B subunit of heat-labile enterotoxin.