DEVELOPMENT OF MONOCLONAL-ANTIBODIES TO THE LANTIBIOTIC NISIN-A

Monoclonal antibodies were prepared against nisin A (nisA), an antimic robial peptide that is used as a food preservative and is produced by strains of Lactococcus lactis subsp. lactis. NisA antibodies were secr eted by hybridomas derived from mice immunized with a nisA-keyhole lim pet hemocyanin conjugate. Competitive direct enzyme-Linked immunoabsor bent assays (CD-ELISA) were devised whereby free nisA and nisA-horsera dish peroxidase competed for antibody binding. The detection limit for nisA in this assay was 10 ng/mL. Antibodies also cross-reacted with n isin Z (nisZ). Mean concentrations of nisA and nisZ required to inhibi t 50% antibody binding for the selected clones were 1180 and 3750 ng/m L, respectively. When the nisA CD-ELISA performance was assessed in sp iked(250, 1250, and 5000 ng/g) spread cheese, the average recovery was 116.5%, with mean intra- and interassay coefficients of variation of 13.3 and 14.1%, respectively.