Mathematical Modelling of the Inhibitory Role of Regulatory T Cells in Tumor Immune Response

Figure 9

(a) Choose different . Stability region of and Hopf bifurcation curve in parameter plane. is stable to the left of the curve and unstable to the right of the curve. (b) Combined immunotherapy surface. is stable below the surface and unstable above the surface. (c) When , the bifurcation diagram of with respect to for system (34). Hopf bifurcation point appears at . (d) Choose different . The bifurcation diagram of with respect to (the stable steady state is represented by the blue curve, and the unstable one corresponds to the red curve).

(a)

(b)

(c)

(d)