Figure 1.

Two pathogens ($x$ and $y$) activate the naïve T-cells ($T_n$ via antigen-presenting cells (APC) into specific effector cells ($T_x$ and $T_y$, respectively) which try to defeat the pathogens. All cell types may be eliminated with natural death rates and the pathogen by additional rates dependent on the number of specific effector cells. The naïve T-cells are upregulated by a baseline production (α). The pool of specific effector T-cells may affect each other through related cytokines, and these may expose an additional effect on the pathogens (green dotted curves). Such effects may be stimulating, neutral, or inhibiting. The mutual inhibiting case considered in this paper is denoted, the immune-competition model.