title: LFA-1/ICAM-1 interaction lowers the threshold of B cell activation by facilitating B cell adhesion and synapse formation.
abstract: The integrin LFA-1 and its ligand ICAM-1 mediate B cell adhesion, but their role in membrane-bound antigen recognition is still unknown. Here, using planar lipid bilayers and cells expressing ICAM-1 fused to green fluorescence protein, we found that the engagement of B cell receptor (BCR) promotes B cell adhesion by an LFA-1-mediated mechanism. LFA-1 is recruited to form a mature B cell synapse segregating into a ring around the BCR. This distribution is maintained over a wide range of BCR/antigen affinities (10(6) M(-1) to 10(11) M(-1)). Furthermore, the LFA-1 binding to ICAM-1 reduces the level of antigen required to form the synapse and trigger a B cell. Thus, LFA-1/ICAM-1 interaction lowers the threshold for B cell activation by promoting B cell adhesion and synapse formation.
authors.affiliation: Lymphocyte Interaction Laboratory, Cancer Research UK London Research Institute, Lincoln's Inn Fields Laboratories, 44 Lincoln's Inn Fields, London WC2A 3PX, United Kingdom.
authors.forename: Yolanda R
authors.initials: YR
authors.lastname: Carrasco
authors.forename: Sebastian J
authors.initials: SJ
authors.lastname: Fleire
authors.forename: Thomas
authors.initials: T
authors.lastname: Cameron
authors.forename: Michael L
authors.initials: ML
authors.lastname: Dustin
authors.forename: Facundo D
authors.initials: FD
authors.lastname: Batista
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology*; D002448:Cell Adhesion / Q000276:immunology; D018799:Intercellular Adhesion Molecule-1 / Q000276:immunology*; D008051:Lipid Bilayers; D008213:Lymphocyte Activation / Q000276:immunology*; D016169:Lymphocyte Function-Associated Antigen-1 / Q000276:immunology*; D051379:Mice; D008822:Mice, Transgenic; D018613:Microscopy, Confocal; D016133:Polymerase Chain Reaction; D011947:Receptors, Antigen, B-Cell
chemical_list: D008051:Lipid Bilayers; D016169:Lymphocyte Function-Associated Antigen-1; D011947:Receptors, Antigen, B-Cell; D018799:Intercellular Adhesion Molecule-1