Figure A. Sandwich ELISA for purified IgA2 using IgA monoclonal antibody, clone KT41 (Cat # MAB9733) coated plate and HRP conjugated KT40. IgE is a negative control. Figure B. Sandwich ELISA for human serum using IgA monoclonal antibody, clone KT41 (Cat # MAB9733) coated plate and HRP conjugated KT40.