B cells acquire antigen from target cells after synapse formation.
Soluble antigen binds to the B-cell antigen receptor and is internalized for subsequent processing and the presentation of antigen-derived peptides to T cells. Many antigens are not soluble, however, but are integral components of membrane; furthermore, soluble antigens will usually be encountered in vivo in a membrane-anchored form, tethered by Fc or complement receptors. Here we show that B-cell interaction with antigens that are immobilized on the surface of a target cell leads to the formation of a synapse and the acquisition, even, of membrane-integral antigens from the target. B-cell antigen receptor accumulates at the synapse, segregated from the CD45 co-receptor which is excluded from the synapse, and there is a corresponding polarization of cytoplasmic effectors in the B cell. B-cell antigen receptor mediates the gathering of antigen into the synapse and its subsequent acquisition, thereby potentiating antigen processing and presentation to T cells with high efficacy. Synapse formation and antigen acquisition will probably enhance the activation of B cells at low antigen concentration, allow context-dependent antigen recognition and enhance the linking of B- and T-cell epitopes.
Batista
F D
FD
Medical Research Laboratory of Molecular Biology, Cambridge, UK. fdb@mrc-lmb.cam.ac.uk
Iber
D
D
Neuberger
M S
MS
D000818:Animals; D017951:Antigen Presentation; D000954:Antigens, Surface / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology*; D002450:Cell Communication; D002460:Cell Line; D004705:Endocytosis; D006801:Humans; D051379:Mice; D008822:Mice, Transgenic; D009113:Muramidase / Q000276:immunology; D011947:Receptors, Antigen, B-Cell / Q000276:immunology
D000954:Antigens, Surface; D011947:Receptors, Antigen, B-Cell; C421864:hen egg lysozyme; D009113:Muramidase