Related Experiment Video
Updated: Jun 14, 2025
07:12
Mouse Naïve CD4+ T Cell Isolation and In vitro Differentiation into T Cell Subsets
Published on: April 16, 2015
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A CD4+ T cell-intrinsic complement C5aR2-prostacyclin-IL-1R2 axis orchestrates Th1 cell contraction
Jubayer Rahman1, Jack A Bibby1, Parul Singh1
1Complement and Inflammation Research Section, NHLBI, NIH, Bethesda, MD 20892, USA.
Immunity
|May 31, 2025
Summary
Complement C5 triggers a pathway that reduces T helper 1 (Th1) cell activity by shifting lipid mediator production. This mechanism, when disrupted, causes persistent Th1 inflammation in autoimmune diseases.
Area of Science:
- Immunology
- Molecular Biology
- Inflammation Research
Background:
- T helper 1 (Th1) cell initiation is understood, but their contraction pathways are not.
- Persistent Th1 cell activity contributes to various inflammatory conditions.
Purpose of the Study:
- To elucidate the molecular mechanisms controlling Th1 cell contraction.
- To identify potential therapeutic targets for inflammatory diseases characterized by excessive Th1 cell activity.
Main Methods:
- Investigated a CD4+ T cell-autonomous pathway involving complement C5.
- Analyzed lipid mediator production (PGE2 and PGI2) and receptor signaling (C5aR2, PGI2 receptor).
- Examined the role of IL-1 receptor type 2 (IL-1R2) in sequestering IL-1β.
Main Results:
- Complement C5 activation of C5aR2 shifts lipid mediator production from PGE2 to PGI2.
- This shift promotes autocrine PGI2 signaling, leading to IL-1R2 expression and IL-1β sequestration.
- Disruption of the C5aR2-PGI2-R axis is linked to persistent Th1 activity in CAPS, Crohn's disease, and rheumatoid arthritis.
- Selective PGE2 synthase inhibition reversed hyperactive Th1 cell phenotype in vitro.
Conclusions:
- Complement C5 is a critical regulator of prostanoid metabolism influencing Th1 cell contraction.
- The C5aR2-PGI2-R axis represents an intrinsic checkpoint for terminating Th1 cell effector responses.
- This pathway is a potential therapeutic target for inflammatory disorders.
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