Modelling the self-tolerance mechanisms of T cells: An adaptive sliding mode control approach

The response of the immune system to self or foreign tissues induce dynamics which lead to health or disease. The maintenance of the healthy state by the inhibition of undesirable responses to self tissues is a key property of the naturally occurring robust feedback mechanism seen within a healthy immune system. In this paper, Variable Structure Control (VSC) theory is used to design an adaptive sliding mode control to model the observed self-tolerance exhibited by a healthy immune system. A suitable sliding manifold and corresponding reachability condition are formulated based on knowledge of the healthy tolerance steady-state. Unlike existing candidate immune response functions, the proposed control function exhibits robust performance commensurate with the self-tolerance mechanisms of the immune system which have been observed experimentally.