The dissociation activation model of B cell antigen receptor triggering

To detect its cognate antigen, each B lymphocyte contains up to 120 000 B cell antigen receptor (BCR) complexes on its cell surface. How these abundant receptors remain silent on resting B cells and how they can be activated by a molecularly diverse set of ligands is poorly understood. The antigen-specific activation of the BCR is currently explained by the cross-linking model (CLM). This model predicts that the many BCR complexes on the surface of a B cell are dispersed signalling-inert monomers and that it is BCR dimerization that initiates signalling from the receptor. The finding that the BCR forms auto-inhibited oligomers on the surface of resting B cells falsifies these predictions of the CLM. We propose the dissociation activation model (DAM), which fits better with the existing body of experimental data. (C) 2010 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.