An antibody to the beta-secretase cleavage site on amyloid-beta-protein precursor inhibits amyloid-beta production.
Proteolytic cleavage of amyloid-beta-protein precursor (AbetaPP) by beta- and gamma-secretases results in production of the amyloid-beta peptide (Abeta) that accumulates in the brains of sufferers of Alzheimer's disease (AD). We have developed a monoclonal antibody, 2B12, which binds in the vicinity of the beta-secretase cleavage site on AbetaPP but does not bind within the Abeta region. We hypothesised that this antibody, directed against the substrate rather than the enzyme, could inhibit cleavage of AbetaPP by beta-secretase via steric hindrance and thus reduce downstream production of Abeta. The antibody would enter cells by binding to AbetaPP when it is at the cell surface and then be internalised with the protein. We subsequently demonstrated that, after addition of 2B12 to standard growth media, this antibody was indeed capable of inhibiting Abeta40 production in neuroblastoma and astrocytoma cells expressing native AbetaPP, as measured by an ELISA. This inhibition was both concentration- and time-dependent and was specific to 2B12. We were only able to inhibit approximately 50% of Abeta40 production suggesting that not all AbetaPP is trafficked to the cell surface. We propose that this antibody could be used as a novel, putative therapy for the treatment of AD.
Thomas
Rhian S
RS
Welsh School of Pharmacy, Cardiff University, Redwood Building, King Edward VII Avenue, Cardiff, CF10 3XF, UK.
Liddell
J Eryl
JE
Murphy
Lynne S
LS
Pache
David M
DM
Kidd
Emma J
EJ
D053829:Amyloid Precursor Protein Secretases / Q000276:immunology*; D016229:Amyloid beta-Peptides / Q000378:metabolism*; D016564:Amyloid beta-Protein Precursor / Q000276:immunology*; D000911:Antibodies, Monoclonal / Q000494:pharmacology*; D001254:Astrocytoma / Q000378:metabolism; D001666:Binding Sites, Antibody / Q000276:immunology; D001932:Brain Neoplasms / Q000378:metabolism; D045744:Cell Line, Tumor; D004305:Dose-Response Relationship, Drug; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D066298:In Vitro Techniques; D009447:Neuroblastoma / Q000378:metabolism; D010446:Peptide Fragments / Q000378:metabolism
D016229:Amyloid beta-Peptides; D016564:Amyloid beta-Protein Precursor; D000911:Antibodies, Monoclonal; D010446:Peptide Fragments; D053829:Amyloid Precursor Protein Secretases