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Time-lapse 3D Imaging of Phagocytosis by Mouse Macrophages
Published on: October 19, 2018
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Submicron-Sampling of Living Cells by Macrophages.
Amy C Fan1, Rukman Thota1,2, Nina Serwas1,3
1Department of Pathology, University of California San Francisco, San Francisco, CA, USA.
Biorxiv : the Preprint Server for Biology
|December 11, 2025
Summary
The immune system samples living cells through a novel, non-destructive process called trogocytosis. This direct cell sampling by macrophages influences T cell responses and maintains immune tolerance.
Area of Science:
- Immunology
- Cell Biology
- Molecular Biology
Background:
- The immune system distinguishes self from non-self to prevent autoimmunity.
- Self-antigens are typically acquired through cell death and vesicle uptake.
- Macrophages play a key role in immune surveillance and antigen presentation.
Purpose of the Study:
- To investigate an alternative mechanism of self-antigen sampling by macrophages.
- To characterize the process of direct sampling of living cells by macrophages.
- To understand the immunological consequences of this sampling mechanism.
Main Methods:
- Utilized advanced imaging and vesicular labeling technologies.
- Employed a high-dimensional flow-based method for analyzing ingested vesicles.
- Investigated the effects of disrupting antigen trafficking pathways.
Main Results:
- Discovered macrophages directly sample living cells via trogocytosis, a non-destructive process.
- Live-sampled material is processed differently, with reduced lysosomal fusion.
- This process differentially affects CD4 and CD8 T cell presentation, impacting T cell priming.
Conclusions:
- Macrophages engage in significant sampling of living cells, distinct from cell death pathways.
- This live-cell sampling mechanism is crucial for immune tolerance and maintaining the immune system's border.
- Targeting antigen trafficking pathways alters macrophage-mediated T cell priming.
