Combination of specific monoclonal antibodies allow identification of soluble aggregates of by sandwich ELISA

Abstract

Aggregate amyloid beta protein 1-42 (A β 1-42 ) can typically be found in the early stage of Alzheimer’s disease (AD). A β 1-42 self-assembles and is highly toxic to neurons. Thus, recognizing aggregated A β 1-42 is very important for elucidation of A β 1-42 structure and for the diagnosis of AD. In this study, the specificity of the 79-3 monoclonal antibody against soluble aggre- gate A β 1-42 was measured by sandwich Enzyme-Linked Immuno Sorbent Assay (ELISA). Eight mono clonal antibodies against both soluble aggregates and amorphous aggregates were used as primary antibodies. Soluble aggregates and amorphous aggregates were used as antigen. As secondary antibody, HRP was labeled with the 79-3 monoclonal antibody. The reactivity of the 79-3 monoclonal antibody against soluble aggregates was confirmed in all combinations, but little reactivity against amorphous aggregates was found. Furthermore, we performed the above sandwich ELISA using the 37-11 antibody, which is reac tive a gainst large oval aggregates (LOA) that occur in micro aggregates, instead of the 79-3 an tibody. T he 77-3 antibody is 1 of the 8 monoclonal antibo dies against soluble aggregates; amorphous aggregates also reacted with the 37-11 antibody. These re sults indicated that soluble aggregates are specifically recognized by a combination of different antibodies. The combined use of these antibodies can be applied to the diagnosis of AD and to defining the structure of the A β 1-42 .