Heavy-chain complementarity-determining regions determine conformation selectivity of anti-abeta antibodies.

摘要

BACKGROUND/AIMS: Amyloid-beta (Abeta) protofibrils are neurotoxic soluble intermediates in the Abeta aggregation process eventually forming senile plaques in Alzheimer's disease. This Abeta species is a potential biomarker for Alzheimer's disease and also a promising target for immunotherapy. In this study, we investigated the characteristics of conformation-dependent Abeta antibodies specific for Abeta protofibrils. METHODS: Mice were immunized with Abeta protofibrils to generate hybridomas producing Abeta-specific monoclonal antibodies. Binding of antibodies to different Abeta conformations was investigated with inhibition ELISA. The antibodies' complementarity-determining region (CDR) sequences were determined and compared. RESULTS: A majority of the antibodies were of the IgM class, all selectively binding to aggregated Abeta. Two IgG antibodies were generated: one with selective affinity for Abeta protofibrils and the other bound Abeta in all conformations. A high degree of similarity between the heavy-chain CDRs of the conformation-dependent antibodies was found, and all high-affinity Abeta antibodies displayed a high degree of sequence similarity in the light-chain CDRs. CONCLUSION: Sequence similarity in the heavy-chain CDRs is associated with conformation selectivity of the antibodies, while sequence similarity in the light-chain CDRs correlates with the affinity for Abeta.