Heavy-chain complementarity-determining regions determine conformation selectivity of anti-aβ antibodies.
OBJECTIVE
Amyloid-β (Aβ) protofibrils are neurotoxic soluble intermediates in the Aβ aggregation process eventually forming senile plaques in Alzheimer's disease. This Aβ 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 Aβ antibodies specific for Aβ protofibrils.


METHODS
Mice were immunized with Aβ protofibrils to generate hybridomas producing Aβ-specific monoclonal antibodies. Binding of antibodies to different Aβ 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 Aβ. Two IgG antibodies were generated: one with selective affinity for Aβ protofibrils and the other bound Aβ in all conformations. A high degree of similarity between the heavy-chain CDRs of the conformation-dependent antibodies was found, and all high-affinity Aβ antibodies displayed a high degree of sequence similarity in the light-chain CDRs.


CONCLUSIONS
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 Aβ.
Sehlin
Dag
D
Department of Public Health/Molecular Geriatrics, Rudbeck Laboratory Uppsala University, Uppsala, Sweden.
Hedlund
Marie
M
Lord
Anna
A
Englund
Hillevi
H
Gellerfors
Pär
P
Paulie
Staffan
S
Lannfelt
Lars
L
Pettersson
Frida Ekholm
FE
D000682:Amyloid / Q000276:immunology*; D016229:Amyloid beta-Peptides / Q000276:immunology*; D016564:Amyloid beta-Protein Precursor / Q000172:deficiency / Q000276:immunology; D000818:Animals; D000888:Antibodies, Anti-Idiotypic / Q000276:immunology*; D000918:Antibody Specificity / Q000276:immunology*; D022801:Complementarity Determining Regions / Q000276:immunology*; D018604:Epitope Mapping; D007074:Immunoglobulin G / Q000276:immunology; D007143:Immunoglobulin Heavy Chains / Q000276:immunology*; D007075:Immunoglobulin M / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D023421:Models, Animal; D011487:Protein Conformation
D000682:Amyloid; D016229:Amyloid beta-Peptides; D016564:Amyloid beta-Protein Precursor; D000888:Antibodies, Anti-Idiotypic; D022801:Complementarity Determining Regions; D007074:Immunoglobulin G; D007143:Immunoglobulin Heavy Chains; D007075:Immunoglobulin M