Mathematical model for IL-2-based cancer immunotherapy

A basic mathematical model for IL -2 -based cancer immunotherapy is proposed and studied. Our analysis shows that the outcome of therapy is mainly determined by three parameters, the relative death rate of CD 4 + T cells, the relative death rate of CD 8 + T cells, and the dose of IL -2 treatment. Minimal equilibrium tumor size can be reached with a large dose of IL -2 in the case that CD 4 + T cells die out. However, in cases where CD 4 + and CD 8 + T cells persist, the final tumor size is independent of the IL -2 dose and is given by the relative death rate of CD 4 + T cells. Two groups of in silico clinical trials show some short-term behaviors of IL -2 treatment. IL -2 administration can slow the proliferation of CD 4 + T cells, while high doses for a short period of time over several days transiently increase the population of CD 8 + T cells during treatment before it recedes to its equilibrium. IL -2 administration for a short period of time over many days suppresses the tumor population for a longer time before approaching its steady-state levels. This implies that intermittent administration of IL -2 may be a good strategy for controlling tumor size.