P3‐311: Amyloid immunotherapy trials in Alzheimer's disease: Experiences from a memory clinic

matter Ab was over 2 times more abundant in the immunized cases as compared to the non-immunized AD patients. In addition, ELISA-quantified TNF-a levels were, on average, almost 3 times higher in the immunized AD subjects as compared to the non-immunized AD cases. SELDI-TOF mass spectrometry of HPLC-purified peptides demonstrated the presence of Ab40 and Ab42 in monomeric and dimeric forms, peptides with an N-terminus starting at residue Ab17 and an assortment of Ab peptides extended at their C-termini. Western blots revealed APP, tau and their degradation fragments were unaffected by immunization. Conclusions: Our analyses revealed that although immunization consistently disrupted amyloid plaque deposits, individuals exhibited substantial variability in the extent of their response. Increased levels of soluble Ab peptides may have toxic consequences for gray and white matter physiology and cerebrovascular function. Immunization against Ab may be most effectively employed as a prophylactic measure under conditions that will permit rapid Ab clearance or degradation.