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B cell ligand discrimination through a spreading and contraction response.
S J Fleire1, J P Goldman, Y R Carrasco
1Lymphocyte Interaction Laboratory, London Research Institute, Cancer Research UK, 44 Lincoln's Inn Fields, London, WC2A 3PX, UK.
Science (New York, N.Y.)
|May 6, 2006
Summary
B cells dynamically spread and contract on antigen-presenting surfaces, collecting antigens to initiate an immune response. This actin-dependent process is crucial for B cell activation and antigen discrimination.
Area of Science:
- Immunology
- Cell Biology
- Biophysics
Background:
- B cells are crucial for adaptive immunity, recognizing foreign antigens via surface immunoglobulin receptors.
- Activation of B cells is most effective when encountering membrane-bound ligands, initiating downstream signaling cascades.
Purpose of the Study:
- To investigate the early physical dynamics of B cell-antigen interactions.
- To elucidate the mechanisms underlying antigen collection and B cell activation.
- To explore the role of cell mechanics in immune synapse formation.
Main Methods:
- Live-cell imaging of B cell-antigen interactions.
- Pharmacological inhibition of signaling pathways and actin polymerization.
- Brownian dynamic simulations of antigen-B cell interactions.
Main Results:
- B cells exhibit a two-phase response: initial spreading followed by contraction on antigen-presenting membranes.
- This dynamic spreading and contraction process collects bound antigens into a central aggregate.
- The extent of this response is dependent on cellular signaling and actin dynamics, influencing antigen accumulation and B cell activation.
- Simulations support the observed antigen collection and suggest a mechanism for affinity discrimination.
Conclusions:
- B cell dynamic spreading is a critical, actin-dependent early step in immune responses.
- This physical process enhances antigen capture and contributes to the discrimination of antigen affinity.
- Understanding these dynamics provides insights into B cell activation and immune synapse formation.
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