Development of a monoclonal antibody binding okadaic acidand dinophysistoxins-1, -2 in proportion to their toxicityequivalence factors

Okadaic acid (OA) and structurally related toxins dinophysistoxin-1 (DTX-1), and DTX-2,are lipophilic marine biotoxins. The current reference method for the analysis of thesetoxins is the mouse bioassay (MBA). This method is under increasing criticism both froman ethical point of view and because of its limited sensitivity and specificity. Alternativereplacement methods must be rapid, robust, cost effective, specific and sensitive. Althoughpublished immuno-based detection techniques have good sensitivities, they are restrictedin their use because of their inability to: (i) detect all of the OA toxins that contribute tocontamination; and (ii) factor in the relative toxicities of each contaminant. Monoclonalantibodies (MAbs) were produced to OA and an automated biosensor screening assaydeveloped and compared with ELISA techniques. The screening assay was designed toincrease the probability of identifying a MAb capable of detecting all OA toxins. The resultwas the generation of a unique MAb which not only cross-reacted with both DTX-1 andDTX-2 but had a cross-reactivity profile in buffer that reflected exactly the intrinsic toxicpotency of the OA group of toxins. Preliminary matrix studies reflected these results. Thisantibody is an excellent candidate for the development of a range of functional immunochemical-based detection assays for this group of toxins.