Fig. 4.

Determination of the sensitivity of the parent antibody 1E8 (a) and the recombinant Fab antibody 1E8-4b (b) to the amyloid peptides Aβ[1–40], Aβ[1–42] and Aβ[1–43] by ELISA. The peptides were serially diluted with doubling dilutions starting from 50 ng/ml while the concentrations of 1E8 and 1E8-4b were kept constant at 5 μg/ml. 1E8 was detected with antimouse-HRP conjugated antibody while 1E8-4b was probed with M2 anti-Flag antibody and then detected with antimouse-HRP conjugated antibody. Detection was via an ‘o’-phenylenediamine development mixture. The isotype control used was M2 anti-Flag antibody which is a mouse IgG₁.