Application of an anti-idiotypic antibody as a mimetic competing antigen in a direct competitive ELISA for the detection of paralytic shellfish poisoning toxins in shellfish.

The previously developed direct competitive ELISA to detect PSP toxins (PSP-ELISA) was modified by employing an enzyme-conjugated anti-idiotypic antibody as a competing antigen. The detection limit of the modified PSP-ELISA in shellfish tissue was estimated to be 0.07 MU/g. When the modified PSP-ELISA was evaluated using the 192 toxin-contaminated shellfish samples, the modified PSP-ELISA results showed a sensitivity of 100% (88 of 88) and a specificity of 92.3% (96 of 104) compared to the MBA results.