Figure 1.
Relative affinities of tau monoclonal antibodies.
PHF-tau (0.5 µg/ml) purified from Alzheimer brain was used in ELISA in order to determine the relative binding abilities of a battery of tau monoclonal antibodies. In this assay, DA31 and PHF1 have much higher relative affinities for PHF-tau than does MC1.
Figure 2.
P301L mice (n = 13–15 per group) immunized with MC1 or DA31, 3 to 7 months of age.
a) MC1-treated mice display a significant reductions (p = 0.023) in forebrain total tau, while DA31-treated mice do not differ from controls. b) When injecting MC1 the mice exhibit a significant decrease (p = 0.022) in forebrain insoluble pathological tau, and again DA31 fails in exerting any beneficial effect. No significant differences were detected when analyzing the hindbrains of treated versus aged-matched controls (a–b).
Figure 3.
Representative CP13 and RZ3 immunohistochemistry of immunized P301L mice, 3 to 7 months of age.
The CA1 hippocampal region of either MC1 or DA31 treated mice was stained with two different phospho-tau antibodies. A–b) CP13 (pSer202) staining is significantly reduced (p = 0.0018) after injecting MC1 or DA31 (p = 0.046). c-d) RZ3 (pThr231) immunoreactivity displays a significant decrease (p = 0.002) in mice treated with MC1, while DA31 does not show any obvious changes. Results are expressed as percent of area stained.
Figure 4.
Representative CP13 and RZ3 immunohistochemistry of immunized P301L mice, 7 to 10 months of age.
The CA1 hippocampal region of the MC1 treated mice was stained with two different phospho-tau antibodies. a–b) CP13 (pSer202) staining is significantly reduced after injecting MC1, both when comparing 7 and 10 months old controls mice with MC1 treated animals from 7 to 10 months of age (p = 0.016 and p = 0.036 respectively). c–d) RZ3 (pThr231) immunoreactivity displays a significant decrease in mice treated with MC1 from 7 to 10 months of age (p = 0.013). Results are expressed as percent of area stained.
Figure 5.
P301L mice (n = 13–15 per group) immunized with MC1, 7 to 10 months of age.
a) Insoluble tau analysis, using the DA31-DA9hrp ELISA, does not show any obvious change both in forebrain and hindbrain of treated mice. b) In forebrain, the ratios of insoluble pS202 and pThr231 over total tau are significantly reduced (p = 0.0145, p = 0.0196). The hindbrain analysis does not show any effect.
Figure 6.
a) P301L mice were treated with MC1, PHF1 or saline from 7 months of age (200 days): no difference in the survival rate is observed between the animal cohorts. b) The analysis of forebrain and hindbrain insoluble tau does not show any difference between groups, correlating well with the survival rate data.
Figure 7.
IgG do not enter into neuronal cell bodies.
A) Goat anti-mouse IgG1 followed by Streptavidin-HRP staining: some immunoreactivity from the blood vessels, but no detectable staining of neurons. B–C) PG5 (pSer409) staining of brain stem of P301L mice: neuronal staining is readily detectable when present. D) Biotinylated-secondary antibody followed by Streptavidin-HRP staining: no neuronal reactivity is seen. Blood vessels staining is detectable in the hippocampus of the mice. E) The same mouse does show any tau pathology (CP13) in hippocampal pyramidal cells.