PRODUCTION OF HIGHLY SPECIFIC MONOCLONAL-ANTIBODIES TO MONENSIN AND DEVELOPMENT OF A MICROELISA TO DETECT THIS ANTIBIOTIC

Monensin, a polyether antibiotic of molecular weight 671 Da, was conve rted into a hemisuccinate and covalently linked to bovine serum albumi n via the mixed anhydride method. Using this immunogen, polyclonal ant i-monensin antibodies were raised in rabbits and monoclonal antibodies were prepared from mice. The specificity of the anti-monensin antibod ies was examined by using several structural analogues as the immunoge n and by performing direct binding and competitive microELISA assays o n Terasaki plates. Rabbit polyclonal antibodies had a dissociation con stant (K(D)) of 5.5 x 10(-8) M for monensin and reacted with nigericin , an antibiotic structurally related to monensin. In contrast, a mouse monoclonal antibody, 2H8, reacted only with monensin and had a much l ower K(D) = 3 x 10(-8) M for monensin. Monoclonal antibody 2H8 was use d to develop a competitive microELISA able to detect as little as 5 ng /ml of monensin in solution which corresponds to 75 pg or 110 fmol of this hapten per Terasaki well.