Figure 7: cell subtype counter-regulation of the differentiation of the other Th cell subsets from activated naïve Th cells. Counter-regulation serves to allow the development of subset-specific immune responses necessary to eliminate the pathogen/tumor/antigen detected by the APCs and subsequently presented to Th0 cells. Antigen presentation to na├»ve Th0 cells drives their differentiation towards the most appropriate adaptive immune response. Red lines indicate inhibitory influences on Th cell differentiation and green lines illustrate lineage promoting effects. Transcription factor, downstream signaling factors, and cytokines that mediate Th cell subset regulation are indicated. (Green arrows, excitatory; red arrows, inhibitory).