A “Minimal” Basic T-Cell Model

Abstract

We present a basic regulatory model for the cellular immune response of two T cell populations interacting with a specific antigen pool. Analytical study and corresponding stability analysis reveal that our model system accounts for the occurrence of multiple steady states in the absence as well as in the presence of the antigen population. Besides the virgin state, where no population is present, the model exhibits a state of immune memory, one state with low antigen and high helper concentration (tolerance) and one state with high antigen and low helper concentration (disease). While the latter states also allow oscillatory behaviour, injection of high antigen doses allow the system to jump from one attractor to the other. Finally, we discuss the intriguing issue of dynamic diseases.