COMPARISON OF PH AND IONIC-STRENGTH DEPENDENCE OF INTERACTIONS BETWEEN MONOCLONAL-ANTIBODIES AND BOVINE BETA-LACTOGLOBULIN

A panel of 13 monoclonal antibodies (mAbs) against distinct determinan ts on bovine beta-lactoglobulin, a model protein antigen, were examine d and compared for their ability to bind and desorb from the antigen a t differing pHs and ionic strengths by an enzyme-linked immunosorbent assay and elution assay. Among them, mAb 61Cl was found to be highly s ensitive to the pH, and 3 in 4 mAbs directed to the region 42-56 also strongly depended on the change in ionic strength. Because of the larg e proportion of charged amino acid residues in the region 42-56, the e lectrostatic forces are considered to be more predominant than the hyd rophobic interactions in the latter antigen-antibody reactions, thereb y resulting in their high sensitivity to the ionic strength.