Preparation and characterization of polyclonal and monoclonal antibodies against fusarenon‐X

Production and characterization of a monoclonal antibody that cross-reacts with the mycotoxins nivalenol and 4-deoxynivalenol

Nivalenol is a mycotoxin produced by certain fungi that are pathogenic to important cereal crops, in particular maize, wheat, and barley. This toxin, 3alpha,4beta,7alpha,15-tetrahydroxy-12,13-epoxytrichothec-9-en-8-one, is found worldwide and is closely related to 4-deoxynivalenol (DON or vomitoxin), a mycotoxin associated with outbreaks of Fusarium head blight in North America. The literature on the toxicity of nivalenol suggests it is similar, if not more toxic, than DON. Despite the development of rapid immunologically based assays for detecting DON, such assays have not existed for detecting nivalenol without chemical modification of the analyte. This paper describes the development of a monoclonal antibody using a nivalenol-glycine protein conjugate. The monoclonal antibody was most specific for an acetylated form of DON (3-Ac-DON), but it exhibited sensitivity and cross-reactivity that were useful for detecting nivalenol and DON at relevant levels without the need to modify either toxin chemically. In an competitive indirect ELISA format, the concentrations of toxins able to inhibit colour development by 50% (IC50) were 1.7, 15.8, 27.5, 68.9, and 1740 ng ml(-1) for the mycotoxins 3-Ac-DON, DON, nivalenol, 15-Ac-DON, and fusarenon-X, respectively. The antibody was also used to develop a competitive direct ELISA for DON and nivalenol, with IC50's of 16.5 ng ml(-1) (DON) and 33.4 ng ml(-1) (nivalenol). These assays are capable of detecting both DON and nivalenol simultaneously, a property that may be useful in regions where these toxins co-occur or in formats, such as immunoaffinity columns, where co-isolation of both toxins is desirable.

Rapid methods for deoxynivalenol and other trichothecenes

Method development for deoxynivalenol (DON) and other trichothecenes in recent years was driven by the analytical necessities arising from its widespread (and increasing) occurrence in foods and feeds. This has resulted in the establishment of guideline levels for animal feed, tolerable daily intake (TDI) levels for humans, and most importantly, in the prospect of low-tolerance levels for these toxins in foods in the near future. In order to ensure reliable determination of the toxin content at the tolerance levels, routine analytical methods must have detection limits of less than the tolerance level. This paper intends to give an overview of current analytical developments of rapid testing for deoxynivalenol and other trichothecene mycotoxins, with a special focus on antibody-based techniques. This includes high-throughput instrumental analysis for the laboratory environment, as well as rapid visual tests for on-site testing. The applicability of rapid tests within an integrated detection system for mycotoxins in foods is discussed.

Use of monoclonal antibodies for the analysis of mycotoxins

Hybridomas producing monoclonal antibodies against aflatoxin M1, ochratoxin A, zearalenone, T-2 toxin, diacetoxyscirpenol, 3-acetyl-deoxynivalenol, fusarenon X, and roridin A were developed after immunization of BALB/c mice and fusion of the splenocytes with myeloma cells. The antibodies were characterized in terms of immunoglobulin subclass, sensitivity, and specificity. The use of these antibodies in competitive enzyme immunoassays, either as microtiter plate assays or membrane-based quick tests, as well as for the production of immunoaffinity columns is described. The advantages and disadvantages of monoclonal antibodies compared to polyclonal antisera for the improvement of mycotoxin analysis are discussed.

Production and characterization of antibodies against nivalenol tetraacetate

Antibody against nivalenol tetraacetate (tetra-Ac-NIV) was prepared by immunization of rabbits with triacetyl-15-pimelate-NIV conjugated to bovine serum albumin. By using tritiated tetra-Ac-NIV as the test ligand, antibody titers were demonstrated as early as 4 weeks after immunization. Useful antibody for radioimmunoassay (RIA) of tetra-Ac-NIV was obtained 7 weeks after immunization, with one booster injection. Results of competitive RIA revealed that the antibody was most specific to tetra-Ac-NIV. The relative cross-reactivity of this antibody with tetra-Ac-NIV, deoxynivalenol triacetate, and neosolaniol triacetate was found to be 100, 2.2, and less than 1, respectively. Practically no cross-reaction was found with deoxynivalenol, fusarenon X, and NIV. The detection limit for tetra-Ac-NIV by RIA was about 5.0 ng/ml (0.5 ng per assay). The use of this antibody for quantitation of NIV in cereals after acetylation of sample extracts is proposed.