Model for antigen binding by B cell-derived receptors

In this study we investigate receptor–ligand binding in the context of antibody–antigen binding. We established a quantitative mapping between macroscopic binding rates of a deterministic differential equation model and their microscopic equivalents as obtained from simulating the spatiotemporal binding kinetics by a stochastic agent-based model. Furthermore, various properties of B cell-derived receptors like their dimensionality of motion, morphology, and binding valency are considered and their impact on receptor–ligand binding kinetics is investigated. The different morphologies of B cell-derived receptors include simple sperical representations as well as more realistic Y-shaped morphologies. These receptors move in different dimensionalities, i.e. either as membrane-anchored receptors or as soluble antibodies. The mapping of the macroscopic and microscopic binding rates allowed us to quantitatively compare different agent-based model variants for the different types of B cell-derived receptors. Our results indicate that the dimensionality of motion governs the binding kinetics and that this predominant impact is quantitatively compensated by the bivalency of these receptors.