| First Author | Wang A | Year | 2011 |
| Journal | J Neurosci | Volume | 31 |
| Issue | 11 | Pages | 4124-36 |
| PubMed ID | 21411653 | Mgi Jnum | J:308682 |
| Mgi Id | MGI:6726918 | Doi | 10.1523/JNEUROSCI.5077-10.2011 |
| Citation | Wang A, et al. (2011) Robust amyloid clearance in a mouse model of Alzheimer's disease provides novel insights into the mechanism of amyloid-beta immunotherapy. J Neurosci 31(11):4124-36 |
| abstractText | Many new therapeutics for Alzheimer's disease delay the accumulation of amyloid-beta (Abeta) in transgenic mice, but evidence for clearance of preexisting plaques is often lacking. Here, we demonstrate that anti-Abeta immunotherapy combined with suppression of Abeta synthesis allows significant removal of antecedent deposits. We treated amyloid-bearing tet-off APP (amyloid precursor protein) mice with doxycycline to suppress transgenic Abeta production before initiating a 12 week course of passive immunization. Animals remained on doxycycline for 3 months afterward to assess whether improvements attained during combined treatment could be maintained by monotherapy. This strategy reduced amyloid load by 52% and Abeta42 content by 28% relative to pretreatment levels, with preferential clearance of small deposits and diffuse Abeta surrounding fibrillar cores. We demonstrate that peripherally administered anti-Abeta antibody crossed the blood-brain barrier, bound to plaques, and was still be found associated with a subset of amyloid deposits many months after the final injection. Antibody accessed the brain independent of plasma Abeta levels, where it enhanced microglial internalization of aggregated Abeta. Our data support a mechanism by which passive immunization acts centrally to stimulate microglial phagocytosis of aggregated Abeta, but is opposed by the continued aggregation of newly secreted Abeta. By arresting the production of Abeta, combination therapy allows microglial clearance to work from a static amyloid burden toward a significant reduction in plaque load. Our findings suggest that combining two therapeutic approaches currently in clinical trials may improve neuropathological outcome over either alone. |
