Antigen epitope density dependent cell surface discrimination and the role of the lipid rafts

The cell surface is the interface between an extracellular set of signals and the appropriate intracellular cell response. For example, B Lymphocyte activity is determined by the spatial and structural response to soluble of cell bound antigens. In order to correlate experimentally observed cell activities like: cell activation, molecule secretion, anergy, death, survival and cell proliferation to external stimuli, one must model the cell surface dynamics properly. B Lymphocyte activation results from the stimulation by large immune complexes involving antigens, antibodies, rafts and complement actors, all require some compartmentalization of the interacting molecular components for a sufficiently rapidly initiated, localized and sustained transmembrane signaling cascade. To shed light on these mechanisms, a graphically visualized, Monte Carlo simulation of the cell surface dynamics was developed. Currently it represents a feasible, advanced and reliable framework to investigate the cell surface in general. The current work is focused on B cell surface dynamics, where, utilizing our model and using an experimental results on series of synthetic, systematically varied polymers, we present an antigen valence dependent, cell surface discrimination phenomena analysis and determine the effect of lipid rafts on B cell receptor antigen binding dynamics.