Measurement of Clostridium perfringens β-toxin production by surface plasmon resonance immunoassay

A rapid and sensitive assay using surface plasmon resonance (SPR) immunoassay has been developed for the detection of Clostridium perfringens β-toxin. The SPR immunoassay was conducted off-line by passing fermentation broth by a sensor chip coated with a monoclonal antibody specific for C. perfringens β-toxin. Quantitation of toxin using SPR immunoassay was achieved by mass transport analysis; results were obtained within 20 min. The SPR immunoassay was compared with an ELISA and the traditional bioassay for C. perfringens β-toxin. The SPR immunoassay and ELISA detected at least twofold differences in toxin levels at 95% confidence over a broad range of toxin concentrations. The traditional bioassay did not produce the resolution observed with the immunoassays. The SPR immunoassay allows for real-time monitoring of β-toxin accumulation during production and permits the bioengineer to harvest C. perfringens fermentations when toxin is most concentrated. The SPR methodology may be applied to other fermentations to enhance and optimize toxin yields.