Figure 2

Binding of tau aggregation antibodies in an in vivo model. The TBS-soluble fraction was obtained from rTg4510 mice overexpressing human P301L mutant tau (0N4R) and from non-transgenic mice (non-Tg) at 10 months of age. This fraction was then subjected to dot blot (A–D), immunohistochemistry (E, F) and western blot (G) analyses. (A–D) The dot blot analysis detected tau in the occipital cortex homogenates from rTg4510 mice. The following antibodies were used: MC1 (0.74 μg/ml), which reacts with conformational tau aggregates (A, upper panel), pan-tau mouse monoclonal antibody (tau5; A, middle panel), and tau aggregation antibodies 2D6-2C6 (0.74 μg/ml) (B), 2B2-1B6 (C), and 8D6-1F7 (D). Densitometry of tau immunoreactivity was quantified. The levels of MC-1, 2D6-2C6, 2B2-1B6, and 8D6-1F7-reactive tau were normalized by the corresponding tau5-reactive tau levels. Quantitative data are presented as a percentage of non-Tg mice (mean ± SD of 4–5 mice). P values were determined using Student’s t tests. Significance is indicated by *(p < 0.05) shown on black columns comparing non-Tg with rTg4510 mice. (E, F) Immunohistochemistry using the 2D6-2C6 antibody highlighted accumulated tau aggregates (arrows) in the CA3 region (left panels), CA1 region (middle panels), and entorhinal cortex (right panels) of rTg4510 mice (E), but not of non-Tg mice (F). (G) In the western blot analysis, both 2D6-2C6 (left panel) and tau5 (right panel) detected endogenous tau in non-Tg mice.