Monoclonal antibodies requiring coating buffer with low pH for efficient antigen capture in sandwich ELISA: the rarities or practically important phenomena?

This article reexamines some opinions concerning pH requirements for optimal immobilization of monoclonal antibodies (mAbs) by passive adsorption in antigen capture ELISA. It was discovered that substitution of "classical" sodium phosphate (pH 7.5) and carbonate (pH 9.5) coating solutions by acid (pH 2.8) buffers maximized antigen capture 4 out of 10 different tested anti-HBsAg mAbs, resulting in a 1.5-2.5 increase of binding curve coefficients. By measuring both mAbs amounts and functionality, the enhancement effect was attributed to the better preservation of solid phase antibodies activity.