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Updated: Jun 30, 2025
Cell-based Assay to Study Antibody-mediated Tau Clearance by Microglia
Published on: November 9, 2018
Measuring Antibody-Mediated Tau Fibril Uptake in Microglia by Flow Cytometry
1Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC, USA. kfunk@charlotte.edu.
Abstract:
Microglia are brain-resident phagocytic cells, considered to be the innate immune cells of the central nervous system. Microglia respond to both infectious pathogens in the brain and sterile cellular debris, including the proteinaceous aggregates that accumulate in the brains of patients with Alzheimer's disease (AD). Microtubule-associated protein Tau is an intracellular protein that self-aggregates into neurofibrillary tangles in Alzheimer's disease and many other neurodegenerative diseases. Ongoing clinical trials are testing whether therapeutic antibodies specific to Tau protein aggregates can reduce pathological protein deposition and improve the course of disease. Data suggest that Tau-specific antibodies act on extracellular Tau aggregates by promoting uptake into microglia cells and thus preventing its prion-like spread to unaffected neurons. Here we describe a protocol to test the effect of Tau-specific antibodies on Tau uptake into microglia by flow cytometry. Recombinant Tau protein is fibrillized in vitro and tagged with a fluorescent label. Then, fibrillized Tau is incubated with the antibody of interest and applied to microglial cells in culture. Uptake of Tau into microglia is then assessed by measuring fluorescence intensity by flow cytometry. With slight modifications, this assay can be used to test effects of many antibodies, various Tau protein compositions, and different microglial sources in a high-throughput format.
Insights
This study introduces a flow cytometry method to assess how Tau-specific antibodies affect microglia
Area of Science:
- Neuroscience
- Immunology
- Cell Biology
Background:
- Microglia are the central nervous system's innate immune cells, crucial for clearing debris like Tau aggregates in Alzheimer's disease (AD).
- Tau protein aggregates into neurofibrillary tangles, contributing to AD and other neurodegenerative diseases.
- Therapeutic antibodies targeting Tau aggregates are being investigated for their potential to reduce pathology and disease progression.
Purpose of the Study:
- To develop and describe a protocol for evaluating the efficacy of Tau-specific antibodies in promoting Tau aggregate uptake by microglia.
- To establish a method for assessing how antibodies influence the interaction between Tau aggregates and microglia.
Main Methods:
- Fibrillization of recombinant Tau protein in vitro and fluorescent tagging.
- Incubation of fibrillized Tau with specific antibodies.
- Application to cultured microglial cells and assessment of Tau uptake via flow cytometry by measuring fluorescence intensity.
Main Results:
- The described protocol enables quantitative measurement of Tau aggregate uptake into microglia in the presence of Tau-specific antibodies.
- The assay is adaptable for high-throughput screening of various antibodies, Tau compositions, and microglial sources.
Conclusions:
- This flow cytometry-based assay provides a robust method to test Tau-specific antibodies for their ability to enhance microglial clearance of Tau aggregates.
- The protocol facilitates research into antibody-mediated therapeutic strategies for neurodegenerative diseases characterized by Tau pathology.
