Environmental Factors Preceding A40 Monomer to Oligomers and the Detection of Oligomers in Alzheimer's Disease Patient Serum
Figure 3
Affinity of moAbs to pH-modified PrP(23–231) and PrP(90–231) [12]. The pH dependence of the affinity of rFab 13A5 (fuchsia square), mAb 6H4 (green diamond), and mAb MAI–750 (yellow triangle) toward (a) SHaPrP(29–231) and (b) SHaPrP(90–231) after incubation at various pH values within the range 3.0–7.2 was tested. Four acidic residues are clustered in the central region within the nine residues 144–152, and rFab 13A5, mAb 6H4, and mAb MAI–750 could bind in this region. None of these antibodies showed any pH dependence of reactivity toward PrP(29–231), whereas MAI-750 showed a pH dependence around at pH 4 to 5 in its reactivity toward PrP(90–231). A further reduction in the reactivity of MAI-750 at very low pH suggests that the antibody is unable to bind to its epitope when the acidic groups are strongly protonated.
