Immunogold labeling of Alzheimer paired helical filaments with ganglioside MAB A2B5
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J R Clements1, A J Beitz, C R Emory
1Department of Veterinary Biology, University of Minnesota, St. Paul.
Abstract:
The ganglioside monoclonal antibody A2B5 has previously been used at the light microscopic level to label Alzheimer neurofibrillary tangles (NFTs). Light microscopic analysis, however, could not reveal whether the A2B5 antibody-labeled NFTs or membrane fragments associated with NFTs. Therefore, we used pre-embedding immunohistochemical electron microscopy to examine A2B5 labeling of NFT. We found that the A2B5 antibody does indeed label a NFT antigen associated with the paired helical filament (PHF) structure, while no significant labeling of membranes or membrane fragments was observed. However, no clear periodicity of the immunogold label on the PHF was found.
Insights
The A2B5 antibody labels antigens within Alzheimer's neurofibrillary tangles (NFTs), specifically associated with paired helical filaments (PHFs). This electron microscopy study confirms A2B5 targets NFTs, not surrounding membranes.
Area of Science:
- Neuroscience
- Immunohistochemistry
- Electron Microscopy
Background:
- The A2B5 antibody has been used to identify Alzheimer's neurofibrillary tangles (NFTs) via light microscopy.
- Previous studies could not definitively determine if A2B5 labeled NFTs or associated membrane fragments.
Purpose of the Study:
- To clarify the precise target of the A2B5 antibody in Alzheimer's disease pathology using electron microscopy.
- To investigate the association of A2B5 labeling with paired helical filaments (PHFs) within NFTs.
Main Methods:
- Pre-embedding immunohistochemical electron microscopy was employed.
- Ultrastructural localization of A2B5 antibody binding was analyzed.
Main Results:
- A2B5 antibody specifically labels an antigen within NFTs, closely associated with the paired helical filament (PHF) structure.
- No significant A2B5 labeling was observed on membranes or membrane fragments near NFTs.
- A clear periodicity of immunogold labeling on the PHF was not detected.
Conclusions:
- The A2B5 antibody is a reliable marker for NFT pathology in Alzheimer's disease at the ultrastructural level.
- The findings confirm A2B5 targets PHF-associated antigens, excluding membrane components.