A general interactive model for B cell activation. I. The theory.

A quantitative model of the B lymphocyte triggering apparatus is proposed in which mitogen receptors and surface immunoglobulins are described as allosteric proteins that interact with mitogens and antigens. An equation is derived that describes the activation of a cell as a function of the states of these receptors as defined by ligand and receptor concentrations, ligand receptor equilibrium constants, and receptor allosteric constants. We analyze the model and show that different parameter sets will actually generate a description of the one-nonspecific-signal model, the matrix model, or the two-signal model of B cell triggering. We suggest that our general interactive model provides a useful conceptual approach to studies of B cell activation because it encompasses other available models that are individually consistent with some experiments, but mutually exclusive to each other. A companion paper describes a series of experiments that verify the consistency of the general model.