Monoclonal antibody against the turn of the 42-residue amyloid ?-protein at positions 22 and 23.

ABSTRACT: Aggregation of the 42-mer amyloid ?-protein (A?42) plays a critical role in the pathogenesis of Alzheimer's disease (AD). We have proposed a toxic conformer with a turn at positions 22 and 23, as well as a nontoxic conformer with a turn at positions 25 and 26, in A?42 aggregates from systematic proline scanning and solid-state NMR studies. Although recent clinical trials of immunization targeting A?42 aggregates have proved useful, some adverse effects were reported. One of the reasons was hypothesized to be excessive immunoreactions derived from the unintended removal of nontoxic A?42, which plays an important role in the physiological function. To develop a monoclonal antibody for toxic A?42, E22P-A?10-35, a minimum moiety for neurotoxicity containing the turn at positions 22 and 23, was used for the generation of antibodies, following the selection of clones using A?42 mutants of E22P (turn-inducing) and E22V (turn-preventing). The obtained clone (11A1) showed a high binding affinity (K(D) = 10.3 nM) for A?42 using surface plasmon resonance. 11A1 also inhibited the neurotoxicity of A?42 in PC12 cells. Immunohistochemical studies showed that not only extracellular but intracellular amyloid was stained in human AD brains. In Western blotting analyses using human brains, low-molecular weight-oligomers rather than the monomer of A? were readily recognized by 11A1. These results imply that 11A1 could detect toxic A?42 oligomers with the turn at positions 22 and 23 and that 11A1 could be applicable for the therapeutic targeting of toxic A?42 in AD.

SUBMITTER: Murakami K 

PROVIDER: S-EPMC3368655 | biostudies-literature | 2010 Nov

REPOSITORIES: biostudies-literature