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Updated: Aug 8, 2026

Static Adhesion Assay for the Study of Integrin Activation in T Lymphocytes
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B-cell activation by membrane-bound antigens is facilitated by the interaction of VLA-4 with VCAM-1

Yolanda R Carrasco1, Facundo D Batista

  • 1Lymphocyte Interaction Laboratory, Cancer Research UK London Research Institute, Lincoln's Inn Fields Laboratories, London, UK.

The EMBO Journal
|February 4, 2006
PubMed

VCAM-1 is one of the main ligands of VLA-4, an integrin that is highly expressed on the surface of mature B cells. Here we find that coexpression of VCAM-1 on an antigen-bearing membrane facilitates B-cell activation. Firstly, this is achieved by mediating B-cell tethering, which in turn increases the likelihood of a B cell to be activated. Secondly, VLA-4 synergizes with the B-cell receptor (BCR), providing B cells with tight adhesion and enhanced signalling. This dual role of VCAM-1 in promoting B-cell activation is predominantly effective when the affinity of the BCR for the antigen is low. In addition, we show that the VCAM-1 ectodomain alone is sufficient to carry out this function. However, it requires the transmembrane domain to segregate properly into a docking structure characteristic of the B-cell immunological synapse (IS). These results show that the VLA-4/VCAM-1 interaction during membrane antigen recognition enhances B-cell activation and this function appears to be independent of its final peripheral localization at the IS.

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