Antibodies bound to Aβ oligomers potentiate the neurotoxicity of Aβ by activating microglia
Article first published online: 27 JUN 2013
© 2013 International Society for Neurochemistry
Journal of Neurochemistry
Volume 126, Issue 5, pages 604–615, September 2013
How to Cite
J. Neurochem. (2013) 126, 604–615.
- Issue published online: 23 AUG 2013
- Article first published online: 27 JUN 2013
- Accepted manuscript online: 7 JUN 2013 09:25AM EST
- Manuscript Accepted: 5 JUN 2013
- Manuscript Revised: 4 JUN 2013
- Manuscript Received: 28 JAN 2013
- Research Council of Lithuania. Grant Number: LIG-04/2012
- Alzheimer's disease;
- beta amyloid;
Beta amyloid (Aβ) oligomers are thought to contribute to the pathogenesis of Alzheimer's disease. However, clinical trials using Aβ immunization were unsuccessful due to strong brain inflammation, the mechanisms of which are poorly understood. In this study we tested whether monoclonal antibodies to oligomeric Aβ would prevent the neurotoxicity of Aβ oligomers in primary neuronal-glial cultures. However, surprisingly, the antibodies dramatically increased the neurotoxicity of Aβ. Antibodies bound to monomeric Aβ fragments were non-toxic to cultured neurons, while antibodies to other oligomeric proteins: hamster polyomavirus major capsid protein, human metapneumovirus nucleocapsid protein, and measles virus nucleocapsid protein, strongly potentiated the neurotoxicity of their antigens. The neurotoxicity of antibody-oligomeric antigen complexes was abolished by removal of the Fc region from the antibodies or by removal of microglia from cultures, and was accompanied by inflammatory activation and proliferation of the microglia in culture. In conclusion, we find that immune complexes formed by Aβ oligomers or other oligomeric/multimeric antigens and their specific antibodies can cause death and loss of neurons in primary neuronal-glial cultures via Fc-dependent microglial activation. The results suggest that therapies resulting in antibodies to oligomeric Aβ or oligomeric brain virus proteins should be used with caution or with suppression of microglial activation.
Immunization against Aβ in Alzheimer's disease carries a significant risk of neuroinflammation, the mechanisms of which are poorly understood. In this study we show that oligomeric antigens such as Aβ and viral proteins complexed with their specific antibodies can exert neurotoxic effects by Fc-dependent microglia activation. This suggests that therapies using antibodies against oligomeric proteins should be used with caution.