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Geometric Analysis and Partial Differential Equations Seminar
February 21, 2013 @ 10:30 am - 11:30 pm
Dr Peter Kim (University of Sydney)
T cell state transitions and change detection
Numerous immune cells exhibit transitions from inactive to activated states. We focus on T cells and develop a model of T cell activation, expansion, and contraction. Our study suggests that state transitions enable T cells to respond to changes in antigen levels, rather than simply the presence or absence of antigen. A key component that gives rise to this change detector is naïve T cell activation. The activation step separates the slow dynamics of naïve T cells from the fast dynamics of effector T cells. As a result, the T cell population responds to sudden shifts in antigen levels, even if the antigen were present prior to the change. This feature provides a mechanism for T cells to react to rapidly expanding sources of antigen, such as viruses, while maintaining tolerance to gradually changing sources, such as healthy tissue during growth.