Figure 1.

Immunization of old and young Tg-SwDI mice with the Epi-Aβ vaccine formulated in Quil-A adjuvant induces robust and uniform anti-Aβ antibody responses. Anti-Aβ antibody responses in individual mice revealed by ELISA in older 15-month-old (A) or younger 11-month-old (B) mice immunized with the Epi-Aβ vaccine (injection number is reflected on the graphs). C, Functionally active anti-Aβ antibodies: affinity-purified anti-Aβ antibodies from Tg-SwDI immunized mice efficiently block Aβ₄₂ fibril formation. Aβ₄₂ peptide was incubated for up to 7 d alone or in the presence of affinity-purified antibodies or control anti-Aβ N-terminus monoclonal 20.1 antibody (50:1 molar ratio of peptide to antibody). Aliquots were taken at the indicated time, and fluorescent assay for fibril formation was performed with thioflavin T. D, Sera from mice immunized with the Epi-Aβ vaccine recognized Aβ deposits in the brains of Tg-SwDI and Tg2576 mice, as well as the monoclonal 6E10 antibody, and sera from non-immune mice were negative (data not shown). E, Affinity-purified anti-Aβ antibodies from Epi-Aβ vaccine immunized mice as well as control 6E10 antibodies recognize monomers and higher oligomeric forms of synthetic Aβ₄₀-DI peptide on a Western blot. F, Pooled serum from multiple mice immunized with Quil-A–Epi-Aβ recognize Aβ₄₀-DI and wild-type human Aβ₄₂ peptides equally well on ELISA plates, as well as control MAb20.1 antibody. OD, Optical density.