Math Biology Seminar: Peter Kim

In a healthy immune system, the T cell response discriminates between self and nonself cells. Medical research has shown that this phenomenon is not black-and-white, since the immune system always contains T cells that could react against self antigens, but are kept suppressed by other immune cells. The solution also cannot only involve a simple bistable system that shifts between immune and tolerant modes, because the T cell response has to be immunogenic to nonself and tolerogenic to self at the same time. We propose that the immune system resolves this difficulty by producing T cell responses that are localized in the vicinity of antigen-presenting cells (APC), which act as information collectors and T cell interaction hubs in the lymph node. We develop an ordinary differential equation model that considers helper, killer, and regulatory T cells. Helper T cells stimulate the immune response, while regulatory T cells suppress it. All T cells interact with each other and with APCs and migrate among APC microenvironments.