Production and characterization of monoclonal antibodies cross‐reactive with major aflatoxins

Monoclonal antibodies cross‐reactive with four major aflatoxins (AFs) were produced by fusion of P3/NS‐1/1‐AG4–1 murine myeloma cells with spleen cells isolated from a BALB/c mouse that had been immunized with aflatoxin B3‐hemisuccinate conjugated to bovine serum albumin. Six stable clones were obtained. Isotyping by enzyme‐linked immunosorbent assay (ELISA) revealed that the antibodies produced by all but two of the clones were of the IgG1 type. Of the remaining clones, one produced IgG21, and the other IgA. Competitive radioimmunoassay using tritiated AFB1 as the marker ligand revealed that two clones produced antibody that cross‐reacted well with both AFB1 and AFG1; one clone produced an antibody that had good specificity toward AFB1. The relative cross‐reactivities (RCR) of antibody produced by clone 575B8F12 for AFB1, AFB2, AFG1, and AFG2 were 100, 5, 153, and 6, respectively. The RCR of antibody produced by clone 575G4H7 for the above AFs were 100, 40, 153, and 40, respectively. The RCR of antibody produced by clone 585D4D6 for the above AFs were 100, 40, 152, and 23, respectively. Antibodies produced by the other three clones were inadequate for immunoassay because their affinities for the AFs were 100 times less than the three clones described above.