The regulatory network that controls the differentiation of T lymphocytes.

There is a vast amount of molecular information regarding the differentiation of T lymphocytes, in particular regarding in vitro experimental treatments that modify their differentiation process. This publicly available information was used to infer the regulatory network that controls the differentiation of T lymphocytes into CD4(+) and CD8(+) cells. Hereby we present a network that consists of 50 nodes and 97 regulatory interactions, representing the main signaling circuits established among molecules and molecular complexes regulating the differentiation of T cells. The network was converted into a continuous dynamical system in the form of a set of coupled ordinary differential equations, and its dynamical behavior was studied. With the aid of numerical methods, nine fixed point attractors were found for the dynamical system. These attractors correspond to the activation patterns observed experimentally for the following cell types: CD4(-)CD8(-), CD4(+)CD8(+), CD4(+) naive, Th1, Th2, Th17, Treg, CD8(+) naive, and CTL. Furthermore, the model is able to describe the differentiation process from the precursor CD4(-)CD8(-) to any of the effector types due to a specific series of extracellular signals.