Mathematical modeling for the regulation of the T helper cell differentiation in the immune system

An immune system is regulated by interactions between many immune cells and molecules. We develops mathematical models by simplifying the complex network of the interactions between cells and regulatory molecules. The models describe the interactions between T helper cell activities and regulatory molecules in the immune system, in response to various levels of sensitization. Analysis of the models illustrates the mono-, bi-, and oneway-switches in the key regulatory parameter sets in the absence or presence of time delays. The models predict coexistence of those phenotypes and Th1- or Th2-dominant immune responses in a spatial domain under various conditions in the microenvironment. Stochasticity also enables immune responses to move into another phenotypes without time delays or spatial effects.