Competitive ELISA employing monoclonal antibodies specific for dothistromin

Dothistromin (DOTH) is a fungal toxin occurring in Pinus radiata needles contaminated with Dothistroma pini. Monoclonal antibodies (MAbs) of high affinity were prepared against DOTH and incorporated into competitive ELISAs. MAbs were secreted by hybri‐doma prepared from mice immunized with DOTH conjugated, through the aromatic ring of the anthraquinone, to bovine serum albumin. DOTH could be quantitated at 2–60 ng ml^‐1 (0.1–2 ng/assay) and at 8–300 ng ml^‐1 (0.4–15 ng/assay) using peroxidase‐labelled MAb 10C12A5 and MAb 6A2D4 respectively in indirect competitive ELISA. The corresponding limits of detection of DOTH were < 300 pg and 1 ng ml^‐1 respectively. The furan ring was an important structure in the epitope recognized by both MAbs.