Understanding how antigen mobility and adhesion molecules influence B cell activation.

Abstract

B cells are activated by specific binding events between antigen and the B cell receptor (BCR). B cells sense physical properties of the antigen-presenting cell, such as antigen mobility, through forces loaded onto BCR-antigen bonds. The LFA-1-ICAM-1 interaction also promotes traction forces at the B cell immune synapse and has been shown to promote B cell activation. In contrast to the biochemical mechanisms governing B cell activation, the role of physical factors remains not fully explored. Here, we systematically explore the role of antigen mobility on B cell activation, investigating a role for both the BCR and LFA-1 integrin. We control forces loaded onto BCR-antigen bonds by manipulating substrate viscosity and controlling antigen density. Understanding how forces on BCR-antigen bonds influence B cell behaviour can help us develop better predictive models of B cell activation and routes to control it.