Immunoreactivity of phage library-derived human single-chain antibodies to amyloid beta conformers in vitro.
The pathogenesis of Alzheimer's disease involves conformational changes of A beta. A series of antibodies recognizing a distinct conformation of A beta (snapshot antibody) is useful for both understanding the mechanism of molecular conversion and identifying diagnostic and therapeutic reagents. As A beta with various conformations can be prepared in vitro under varying physicochemical conditions, snapshot antibodies can be isolated by directly binding to target molecules with antibody-displaying phages. We tested the feasibility of this idea. We show a feature of several A beta-reactive antibodies isolated from our human single-chain Fv antibody-phage library and particularly report the characteristics of an scFv clone, B6, selected from the fibrillar A beta 1-42-coated biopanning. B6 bound to fibrillar A beta 1-42 as well as globulomer A beta 1-42 but not to soluble A beta 1-42 or A beta 1-40. B6 inhibited A beta 1-42 fibril formation with 600 nM IC50 in spite of being the monovalent scFv form. Epitope analysis suggested that the binding site might be located at the beta2 sheet of the C-terminus of A beta 1-42. Although it is believed that N-terminus-recognizing antibodies tend to show the capability to inhibit A beta 1-42 fibrillation, B6 is the first human inhibitory antibody recognizing the C-terminus of A beta 1-42.
Yoshihara
Tomoki
T
Department of Bioengineering, Faculty of Engineering, Kagoshima University, Korimoto 1-21-40, Kagoshima, Kagoshima, Japan.
Takiguchi
Sho
S
Kyuno
Akifumi
A
Tanaka
Koichi
K
Kuba
Sayaka
S
Hashiguchi
Shuhei
S
Ito
Yuji
Y
Hashimoto
Tadafumi
T
Iwatsubo
Takeshi
T
Tsuyama
Shinichiro
S
Nakashima
Toshihiro
T
Sugimura
Kazuhisa
K
D000595:Amino Acid Sequence; D016229:Amyloid beta-Peptides / Q000737:chemistry / Q000276:immunology*; D000906:Antibodies / Q000235:genetics / Q000276:immunology*; D001435:Bacteriophages / Q000235:genetics*; D001483:Base Sequence; D017931:DNA Primers; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D008969:Molecular Sequence Data; D011487:Protein Conformation; D017386:Sequence Homology, Amino Acid
D016229:Amyloid beta-Peptides; D000906:Antibodies; D017931:DNA Primers