I. Introduction
T lymphocytes (T cells) are an integral part of the human body's natural defense against the threats of invading pathogens and cancerous cells. Engagement of T cell receptors (TCRs) immediately initiates intracellular signal transduction pathways resulting in the activation of transcription factors that ultimately direct the cell's action. During this process, manipulations to the early signaling events within the transduction pathways can alter the cell's response through changes to the active transcription factor profile. Traditional biochemical assays can monitor only a limited number of signaling molecules and do not support real-time observations. As a result, open-loop control provides a suitable tool for designing systematic manipulations to obtain desired signaling responses.