ABSTRACT
OBJECTIVES: To detect the reactivity pattern of sera from patients with mild and severe Alzheimer's disease (AD) to specific antibodies targeting different epitopes in the primary structure of amyloid-beta (Abeta). MATERIALS AND METHODS: Sera from patients diagnosed with mild or severe AD were used. The reactivity of sera to monoclonal antibodies recognizing 1-7, 5-10, 9-14 and 17-21 epitopes of Abeta1-40 at 36-42 degrees C was determined by an enzyme-linked immunosorbent assay. Proteinase K digestion of Abeta1-40 was investigated by dot blotting at 36 and 40 degrees C. RESULTS: Sera of patients with AD displayed reactivity only with monoclonal antibody recognizing the epitope 17-21 (4G8). The reactivity of sera from patients with severe AD was less than that of sera from patients with mild AD at temperatures 36-41 degrees C, with no difference at 42 degrees C. Patients with severe AD displayed lesser digestion with proteinase K. CONCLUSIONS: Sera derived from patients with AD could react with monoclonal antibodies directed to 17-21 sequences of Abeta1-40 in a temperature-dependent manner. The severity of AD is associated with greater Abeta1-40 aggregation and resistance to proteinase K. The present results may be of value in staging and following up of patients with AD.
