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Comparing the efficacy and neuroinflammatory potential of three anti-abeta antibodies.

Fuller JP, Stavenhagen JB, Christensen S, Kartberg F, Glennie MJ, Teeling JL - Acta Neuropathol. (2015)

Bottom Line: In this study, we directly compared 3 clinical candidates in the same pre-clinical model, with the same effector function, for their ability to clear plaques and induce inflammation in the brain.This translated into 3D6 effectively clearing plaques and reducing the levels of insoluble Aβ, whilst chGantenerumab and mC2 did not. 3D6 caused a significant increase in the levels of pro-inflammatory cytokines IL-1β and TNFα, and an associated increase in microglial expression of CD11B and CD68. chGantenerumab increased pro-inflammatory cytokines and microglial activation, but minimal changes in CD68, as an indicator of phagocytosis.Injection of mC2 did not cause any significant inflammatory changes.

View Article: PubMed Central - PubMed

Affiliation: Centre for Biological Sciences, University of Southampton, Southampton, UK. jpf1g11@soton.ac.uk.

ABSTRACT
Immunotherapy is a promising strategy for the treatment of Alzheimer's disease (AD). Antibodies directed against Amyloid Beta (Aβ) are able to successfully clear plaques and reverse cognitive deficits in mouse models. Excitement towards this approach has been tempered by high profile failures in the clinic, one key issue has been the development of inflammatory side effects in the brain (ARIAs). New antibodies are entering the clinic for Alzheimer's disease; therefore, it is important to learn all we can from the current generation. In this study, we directly compared 3 clinical candidates in the same pre-clinical model, with the same effector function, for their ability to clear plaques and induce inflammation in the brain. We produced murine versions of the antibodies: Bapineuzumab (3D6), Crenezumab (mC2) and Gantenerumab (chGantenerumab) with an IgG2a constant region. 18-month transgenic APP mice (Tg2576) were injected bilaterally into the hippocampus with 2 µg of each antibody or control. After 7 days, the mice tissue was analysed for clearance of plaques and neuroinflammation by histology and biochemical analysis. 3D6 was the best binder to plaques and in vitro, whilst mC2 bound the least strongly. This translated into 3D6 effectively clearing plaques and reducing the levels of insoluble Aβ, whilst chGantenerumab and mC2 did not. 3D6 caused a significant increase in the levels of pro-inflammatory cytokines IL-1β and TNFα, and an associated increase in microglial expression of CD11B and CD68. chGantenerumab increased pro-inflammatory cytokines and microglial activation, but minimal changes in CD68, as an indicator of phagocytosis. Injection of mC2 did not cause any significant inflammatory changes. Our results demonstrate that the ability of an antibody to clear plaques and induce inflammation is dependent on the epitope and affinity of the antibody.

No MeSH data available.


Related in: MedlinePlus

Anti-Aβ immunohistochemistry and congophilic plaque load. a Tissue sections from Tg2576 mice injected with antibodies were immuno-stained for Aβ, and the percentage staining area above threshold was measured. Data were analysed by Kruskal–Wallis and Dunn’s post hoc test and expressed as mean ± SD (n = 6/7). 3D6 significantly reduced Aβ load compared to mC2 and chGantenerumab (p = 0.0265 and p = 0.0013, respectively). Images taken with a ×10 objective, scale bar 250 µm. b To test for clearance of congophilic plaques, brain sections from were stained with Congo red. The numbers of congophilic plaques were counted and normalised to hippocampal area and expressed as congophilic plaques/mm2. Data were analysed by one-way ANOVA and Tukey post hoc test and expressed as mean ± SD (n = 6/7). 3D6 significantly reduced the number of congophilic plaques compared to irrelevant IgG2a and chGantenerumab (p = 0.0265 and p = 0.0178, respectively). Images taken with a ×10 objective, scale bar 250 µm
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Fig2: Anti-Aβ immunohistochemistry and congophilic plaque load. a Tissue sections from Tg2576 mice injected with antibodies were immuno-stained for Aβ, and the percentage staining area above threshold was measured. Data were analysed by Kruskal–Wallis and Dunn’s post hoc test and expressed as mean ± SD (n = 6/7). 3D6 significantly reduced Aβ load compared to mC2 and chGantenerumab (p = 0.0265 and p = 0.0013, respectively). Images taken with a ×10 objective, scale bar 250 µm. b To test for clearance of congophilic plaques, brain sections from were stained with Congo red. The numbers of congophilic plaques were counted and normalised to hippocampal area and expressed as congophilic plaques/mm2. Data were analysed by one-way ANOVA and Tukey post hoc test and expressed as mean ± SD (n = 6/7). 3D6 significantly reduced the number of congophilic plaques compared to irrelevant IgG2a and chGantenerumab (p = 0.0265 and p = 0.0178, respectively). Images taken with a ×10 objective, scale bar 250 µm

Mentions: Next, we tested the ability of the anti-Aβ antibodies to clear Aβ in vivo by injecting 2 µg of each antibody into the hippocampus of 18-month-old Tg2576 mice. Clearance of Aβ after intracerebral injection of antibody into Tg2576 mice was quantified by Aβ immuno-staining. Injection of 3D6 significantly reduced Aβ plaque load in comparison to chGantenerumab and mC2 (Fig. 2a, p = 0.0013 and p = 0.026, respectively). Due to the potential of antigenic masking by injected antibodies, Congo red staining was used to detect the clearance of congophilic deposits after antibody injection. 3D6 significantly reduced the number of Congo red-positive plaques in the hippocampus compared to irrelevant IgG2a and chGantenerumab injected animals (Fig. 2b, p = 0.0265 and p = 0.0178, respectively). The results were confirmed by measuring the levels Aβ38, Aβ40 and Aβ42 in brain homogenate. Diffuse (triton soluble) Aβ levels were not affected 7 days post-injection. Supporting the decreased immuno-staining, 3D6 significantly reduced the amount of aggregated (formic acid soluble) Aβ38 compared to Gantenerumab or irrelevant IgG2a injection (Fig. 3d, p = 0.0168 and p = 0.0073, respectively). 3D6 also significantly lowered the amount of aggregated Aβ42 compared to irrelevant IgG2a (Fig. 3f, p = 0.041), and cleared aggregated Aβ40 in 50 % of mice treated with this antibody (Fig. 3e). chGantenerumab and mC2 did not induce significant changes to aggregated Aβ levels.Fig. 2


Comparing the efficacy and neuroinflammatory potential of three anti-abeta antibodies.

Fuller JP, Stavenhagen JB, Christensen S, Kartberg F, Glennie MJ, Teeling JL - Acta Neuropathol. (2015)

Anti-Aβ immunohistochemistry and congophilic plaque load. a Tissue sections from Tg2576 mice injected with antibodies were immuno-stained for Aβ, and the percentage staining area above threshold was measured. Data were analysed by Kruskal–Wallis and Dunn’s post hoc test and expressed as mean ± SD (n = 6/7). 3D6 significantly reduced Aβ load compared to mC2 and chGantenerumab (p = 0.0265 and p = 0.0013, respectively). Images taken with a ×10 objective, scale bar 250 µm. b To test for clearance of congophilic plaques, brain sections from were stained with Congo red. The numbers of congophilic plaques were counted and normalised to hippocampal area and expressed as congophilic plaques/mm2. Data were analysed by one-way ANOVA and Tukey post hoc test and expressed as mean ± SD (n = 6/7). 3D6 significantly reduced the number of congophilic plaques compared to irrelevant IgG2a and chGantenerumab (p = 0.0265 and p = 0.0178, respectively). Images taken with a ×10 objective, scale bar 250 µm
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Fig2: Anti-Aβ immunohistochemistry and congophilic plaque load. a Tissue sections from Tg2576 mice injected with antibodies were immuno-stained for Aβ, and the percentage staining area above threshold was measured. Data were analysed by Kruskal–Wallis and Dunn’s post hoc test and expressed as mean ± SD (n = 6/7). 3D6 significantly reduced Aβ load compared to mC2 and chGantenerumab (p = 0.0265 and p = 0.0013, respectively). Images taken with a ×10 objective, scale bar 250 µm. b To test for clearance of congophilic plaques, brain sections from were stained with Congo red. The numbers of congophilic plaques were counted and normalised to hippocampal area and expressed as congophilic plaques/mm2. Data were analysed by one-way ANOVA and Tukey post hoc test and expressed as mean ± SD (n = 6/7). 3D6 significantly reduced the number of congophilic plaques compared to irrelevant IgG2a and chGantenerumab (p = 0.0265 and p = 0.0178, respectively). Images taken with a ×10 objective, scale bar 250 µm
Mentions: Next, we tested the ability of the anti-Aβ antibodies to clear Aβ in vivo by injecting 2 µg of each antibody into the hippocampus of 18-month-old Tg2576 mice. Clearance of Aβ after intracerebral injection of antibody into Tg2576 mice was quantified by Aβ immuno-staining. Injection of 3D6 significantly reduced Aβ plaque load in comparison to chGantenerumab and mC2 (Fig. 2a, p = 0.0013 and p = 0.026, respectively). Due to the potential of antigenic masking by injected antibodies, Congo red staining was used to detect the clearance of congophilic deposits after antibody injection. 3D6 significantly reduced the number of Congo red-positive plaques in the hippocampus compared to irrelevant IgG2a and chGantenerumab injected animals (Fig. 2b, p = 0.0265 and p = 0.0178, respectively). The results were confirmed by measuring the levels Aβ38, Aβ40 and Aβ42 in brain homogenate. Diffuse (triton soluble) Aβ levels were not affected 7 days post-injection. Supporting the decreased immuno-staining, 3D6 significantly reduced the amount of aggregated (formic acid soluble) Aβ38 compared to Gantenerumab or irrelevant IgG2a injection (Fig. 3d, p = 0.0168 and p = 0.0073, respectively). 3D6 also significantly lowered the amount of aggregated Aβ42 compared to irrelevant IgG2a (Fig. 3f, p = 0.041), and cleared aggregated Aβ40 in 50 % of mice treated with this antibody (Fig. 3e). chGantenerumab and mC2 did not induce significant changes to aggregated Aβ levels.Fig. 2

Bottom Line: In this study, we directly compared 3 clinical candidates in the same pre-clinical model, with the same effector function, for their ability to clear plaques and induce inflammation in the brain.This translated into 3D6 effectively clearing plaques and reducing the levels of insoluble Aβ, whilst chGantenerumab and mC2 did not. 3D6 caused a significant increase in the levels of pro-inflammatory cytokines IL-1β and TNFα, and an associated increase in microglial expression of CD11B and CD68. chGantenerumab increased pro-inflammatory cytokines and microglial activation, but minimal changes in CD68, as an indicator of phagocytosis.Injection of mC2 did not cause any significant inflammatory changes.

View Article: PubMed Central - PubMed

Affiliation: Centre for Biological Sciences, University of Southampton, Southampton, UK. jpf1g11@soton.ac.uk.

ABSTRACT
Immunotherapy is a promising strategy for the treatment of Alzheimer's disease (AD). Antibodies directed against Amyloid Beta (Aβ) are able to successfully clear plaques and reverse cognitive deficits in mouse models. Excitement towards this approach has been tempered by high profile failures in the clinic, one key issue has been the development of inflammatory side effects in the brain (ARIAs). New antibodies are entering the clinic for Alzheimer's disease; therefore, it is important to learn all we can from the current generation. In this study, we directly compared 3 clinical candidates in the same pre-clinical model, with the same effector function, for their ability to clear plaques and induce inflammation in the brain. We produced murine versions of the antibodies: Bapineuzumab (3D6), Crenezumab (mC2) and Gantenerumab (chGantenerumab) with an IgG2a constant region. 18-month transgenic APP mice (Tg2576) were injected bilaterally into the hippocampus with 2 µg of each antibody or control. After 7 days, the mice tissue was analysed for clearance of plaques and neuroinflammation by histology and biochemical analysis. 3D6 was the best binder to plaques and in vitro, whilst mC2 bound the least strongly. This translated into 3D6 effectively clearing plaques and reducing the levels of insoluble Aβ, whilst chGantenerumab and mC2 did not. 3D6 caused a significant increase in the levels of pro-inflammatory cytokines IL-1β and TNFα, and an associated increase in microglial expression of CD11B and CD68. chGantenerumab increased pro-inflammatory cytokines and microglial activation, but minimal changes in CD68, as an indicator of phagocytosis. Injection of mC2 did not cause any significant inflammatory changes. Our results demonstrate that the ability of an antibody to clear plaques and induce inflammation is dependent on the epitope and affinity of the antibody.

No MeSH data available.


Related in: MedlinePlus