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Murine Model of CD40-activation of B cells
Published on: March 5, 2010
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Mechanotransduction governs CD40 function and underlies X-linked hyper-IgM syndrome
Hyun-Kyu Choi1,2,3, Stefano Travaglino1,2, Matthias Münchhalfen4
1Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA 30332, USA.
Science Advances
|November 15, 2024
Summary
T cells and B cells use CD40-CD40L interactions to mature. Mechanical force on these bonds enhances CD40 signaling, crucial for antibody class switch, and its absence causes X-linked hyper-IgM syndrome.
Area of Science:
- Immunology
- Cellular Mechanobiology
- Biophysics
Background:
- B cell maturation relies on T cell interactions, specifically CD40 ligand (CD40L) on T cells engaging CD40 on B cells.
- This interaction, alongside B cell receptor (BCR) signaling, is vital for antibody affinity maturation and class switching.
- Defects in CD40-CD40L interactions lead to X-linked hyper-IgM syndrome (X-HIgM), characterized by impaired antibody responses.
Purpose of the Study:
- To investigate the role of CD40-mediated mechanotransduction in B cell signaling during T cell-B cell interactions.
- To elucidate the biophysical properties of the CD40-CD40L bond and its response to mechanical force.
- To understand how mutations associated with X-HIgM affect CD40-CD40L bond mechanics and downstream signaling.
Main Methods:
- Utilized biophysical techniques to study the mechanical properties of the CD40-CD40L interaction, including force-dependent bond lifetime (catch bonds).
- Measured cellular tension exerted by both T and B cells on CD40-CD40L bonds.
- Assessed the impact of force on CD40 signaling pathways and antibody class switch in B cells.
Main Results:
- Identified that CD40 forms catch bonds with CD40L, with bond duration increasing under higher forces.
- Demonstrated that both T and B cells apply tension to CD40-CD40L bonds.
- Showed that mechanical force enhances CD40 signaling and promotes antibody class switch.
- Found that X-HIgM-associated CD40L mutations disrupt catch bond formation, reduce cellular tension, and impair force-enhanced CD40 signaling.
Conclusions:
- CD40-CD40L interactions exhibit catch bond behavior, where force strengthens the interaction.
- Mechanotransduction, specifically the application of tension, is a critical regulator of CD40 signaling and antibody class switch.
- Impaired mechanotransduction due to CD40L mutations provides a mechanistic basis for the immunodeficiency observed in X-HIgM syndrome.
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