What Scales the T Cell Response?

T cells are known to scale their clonal expansion and effector cytokine response according to the dose and strength of antigenic signal so as to balance their role of affecting protection with the intertwined and immunologically driven tissue damage. How T cells achieve this is now beginning to be understood. We underscore temporal integration of digital T cell receptor (TCR) signaling as the basis for achieving scaled response by means of accumulating crucial mediators over time. We also discuss the role of temporally integrated crosstalk between TCR and IL2 signaling in mediating a scaled, coherent, collective response by T cells. Finally, we highlight numerous known and putative regulatory interactions in the transcriptional program that are expected to quantitatively scale the T cell response, and also offer new mechanisms to hitherto unexplained observations.

TrendsThe extent of clonal expansion and effector cytokine production by T cells is largely proportional to antigen dose and strength. This is, in short, referred as a scaled response.A scaled T cell response is an important functional feature of the immune system.Temporal integration of TCR signaling is primarily responsible for a scaled T cell response.Numerous regulatory interactions are involved in ensuring a scaled T cell response. These include crosstalk with cytokine signaling as well as feed-forward and feedback regulation involving transcription factors.