B cell activation is regulated by the stiffness properties of the substrate presenting the antigens
B lymphocytes are activated upon Ag sensing by BCRs. The substrate presenting the Ag can show different degrees of stiffness. It is not clear whether B cells can respond to changes in substrate stiffness. In this study we use high-resolution, high-speed live cell imaging techniques to capture the mo...
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Published in | The Journal of immunology (1950) Vol. 190; no. 9; pp. 4661 - 4675 |
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Main Authors | , , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
United States
01.05.2013
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Subjects | |
Online Access | Get full text |
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Summary: | B lymphocytes are activated upon Ag sensing by BCRs. The substrate presenting the Ag can show different degrees of stiffness. It is not clear whether B cells can respond to changes in substrate stiffness. In this study we use high-resolution, high-speed live cell imaging techniques to capture the molecular events in B cell activation after the recognition of Ags tethered to polyacrylamide gel substrates with variable degrees of stiffness as quantified by Young's modulus (2.6-22.1 kPa). We show that the initiation of B cell activation is extremely sensitive to substrate stiffness. B cells exhibit much stronger activation responses when encountering Ags tethered to substrates with a high degree of stiffness as measured by the accumulation of BCR, phospho-spleen tyrosine kinase, and phosphotyrosine molecules into the B cell immunological synapse. Ags tethered to stiff substrates induce the formation of more prominent BCR and phospho-spleen tyrosine kinase microclusters with significantly enhanced colocalization as compared with Ags tethered to soft substrates. Moreover, the expression of the B cell activation marker CD69 is enhanced in B cells encountering Ags on stiffer substrates. Through time-lapse live cell imaging, we find that the different responses of B cells to substrate stiffness are only demonstrated 5 min after BCR and Ag recognition. Using a series of cytoskeleton inhibitors, we determine that the mechanosensing ability of B cells is dependent on microtubules, and only mildly linked to the actin cytoskeleton. These results suggest the importance of the mechanical properties mediated by substrate stiffness in B cell activation. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 ObjectType-Article-2 ObjectType-Feature-1 |
ISSN: | 0022-1767 1550-6606 |
DOI: | 10.4049/jimmunol.1202976 |