Titer and isotype of anti-Aβ antibodies induced by (1–11)E2 formulated in Alhydrogel 2% or AddaVax.

<p><b>panel a</b> The plot reports the anti-Aβ antibody titer at day 14 of B6C3/F1 mice that have received one injection of (1–11)E2, formulated in Alhydrogel 2% (diamonds), AddaVax (circles), or without adjuvant (triangles). Each symbol represents a mouse. Some mice were immunized with LPS-free (1–11)E2 (open symbols) while other mice were immunized with (1–11)E2 obtained with the standard purification protocol (closed symbols). With either adjuvant, the presence of LPS contamination in the (1–11)E2 preparation has no statistically significant effect on the anti-Aβ titer. Both Alhydrogel 2% and AddaVax significantly enhanced the anti-Aβ response induced by LPS-free (1–11)E2, with no significant difference in the anti-Aβ IgG titer obtained with Alhydrogel 2%, or AddaVax. <b>panel b</b> The histograms show the anti-Aβ titer of IgG1 (white bars) and IgG2a (black bars) isotype antibodies in the pooled sera of B6C3/F1 mice (n = 5 in each treatment group) vaccinated with LPS-free (1–11)E2, formulated in the indicated adjuvants. Sera were collected at day 109. The error bars represent the standard deviation, calculated from extreme alternative fit lines. IgG1 antibodies were more abundant than IgG2a in both the Alhydrogel 2% and the AddaVax group. <b>panel c</b> The graph shows the anti-Aβ (1–11) IgG titer in the sera of B6C3/F1 mice immunized with (1–11)E2 formulated in either Alhydrogel 2% or AddaVax. Mice received 3 doses of adjuvanted vaccine, at day 0, 15 and 238. Sera were collected before the day 238 recall dose (black symbols) and 14 days after the day 238 recall dose (open symbols). A memory response was observed both in the Alhydrogel 2% and in the AddaVax group.