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Phenotypic and Functional Analysis of Activated Regulatory T Cells Isolated from Chronic Lymphocytic Choriomeningitis Virus-infected Mice
Published on: June 22, 2016
Basis of CTLA-4 function in regulatory and conventional CD4(+) T cells
Xuguang Tai1, François Van Laethem, Leonid Pobezinsky
1Experimental Immunology Branch, National Cancer Institute, Bethesda, MD 20892, USA.
Cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) externalization grants suppressor function to both regulatory T cells (Tregs) and conventional T cells (Tconv). Intracellular localization is crucial for CTLA-4 protein function.
Area of Science:
- Immunology
- Cell Biology
Background:
- Cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) is crucial for regulatory T cell (Treg) function, but its precise mechanism remains unclear.
- CTLA-4 mediates Treg suppression, TCR hyposignaling, and anergy, key aspects of immune regulation.
Purpose of the Study:
- To elucidate the mechanism of CTLA-4 protein function in Tregs and conventional T cells (Tconv).
- To investigate the role of CTLA-4 domains and intracellular localization in T cell function.
Main Methods:
- Assessed CTLA-4 protein function in Tregs and Tconv cells.
- Analyzed the contribution of CTLA-4's external and internal domains to T cell functions.
- Investigated CTLA-4 protein localization within T cells using microscopy.
Main Results:
- CTLA-4 mediates Treg suppression, TCR hyposignaling, and anergy.
- Treg suppression and anergy depend on CTLA-4's external domain, while TCR hyposignaling requires its internal domain.
- CTLA-4 localization in submembrane vesicles in Tregs facilitates function, whereas Golgi retention in Tconv cells limits it. Tconv cells gain suppressor function upon activation and CTLA-4 externalization.
Conclusions:
- Intracellular localization is critical for CTLA-4 protein function.
- Externalization of CTLA-4 imparts suppressor function to both Tregs and Tconv cells, highlighting a shared mechanism in immune regulation.
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