Premium
B‐cell activation by membrane‐bound antigens is facilitated by the interaction of VLA‐4 with VCAM‐1
Author(s) -
Carrasco Yolanda R,
Batista Facundo D
Publication year - 2006
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1038/sj.emboj.7600944
Subject(s) - biology , library science , computer science
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.