Transient selection in multi-cellular immune networks
M. V. Ivanchenko
Theory of Oscillations Department, University of Nizhniy Novgorod, Russia
Abstract
We analyze the dynamics of a multi-clonotype naive T-cell population
competing for survival signals from antigen-presenting cells. We find that this
competition provides with an efficacious selection of clonotypes, making the
less able and more repetitive get extinct. We uncover the scaling principles for
large systems the extinction rate obeys and calibrate the model parameters to
their experimental counterparts. For the first time we estimate the
physiological values of the T-cell receptor - antigen presentation profile
recognition probability and T-cell clonotypes niche overlap. We demonstrate
that, while the ultimate state is a stable fixed point, sequential transients
dominate the dynamics over large timescales that may span over years, if not
decades, in real time. We argue that what is currently viewed as 'homeostasis'
is a complex sequential transient process, while being quasi-stationary in the
total number of T-cells only. The discovered type of sequential transient
dynamics in large random networks is a novel alternative to the stable
heteroclinic channel mechanism.