Figure 2.

Induction and transcriptional program of the main regulatory and Inflammatory CD4+ T-cell sub-populations. During antigen-specific activation via the T-cell receptor (TCR) and subsequent proliferation in the lymph node naïve CD4⁺ T-cells undergo a functional programming termed differentiation. Depending on the strength of the TCR signal and in response to cytokine co-stimulation by the APC the T-cells express specific transcription factors that skew differentiation to a range of functionalities such as host defense against intracellular pathogens, defense against extracellular pathogens, defense against helminths or immune suppression. Although these differentiation programs are not irreversible classification according to these “subsets” based on dominant cytokine profiles and transcription factors is commonly used to better describe and characterize immune responses.