Isolation of phage-display library-derived scFv antibody specific to Listeria monocytogenes by a novel immobilized method.

AIMS: To select Listeria monocytogenes-specific single-chain fragment variable (scFv) antibodies from a phage-display library by a novel simple and cost-effective immobilization method. METHODS AND RESULTS: Light expanded clay aggregate (LECA) was used as biomass support matrix for biopanning of a phage-display library to select L. monocytogenes-specific scFv antibody. Four rounds of positive selection against LECA-immobilized L. monocytogenes and an additional subtractive panning against Listeria innocua were performed. The phage clones selected using this panning scheme and LECA-based immobilization method exhibited the ability to bind L. monocytogenes without cross-reactivity toward 10 other non-L. monocytogenes bacteria. One of the selected phage clones was able to specifically recognize three major pathogenic serotypes (1/2a, 1/2b and 4b) of L. monocytogenes and 11 tested L. monocytogenes strains isolated from foods. CONCLUSIONS: The LECA-based immobilization method is applicable for isolating species-specific anti-L. monocytogenes scFv antibodies by phage display. SIGNIFICANCE AND IMPACT OF THE STUDY: The isolated scFv antibody has potential use in development of immunoassay-based methods for rapid detection of L. monocytogenes in food and environmental samples. In addition, the LECA immobilization method described here could feasibly be employed to isolate specific monoclonal antibodies against any given species of pathogenic bacteria from phage-display libraries.