Figure 1: Differentiation of naïve T helper cells into particular subsets. T helper lymphocytes leaving the thymus (naïve or T_{H}0) are not yet fully differentiated to perform their specific functions in peripheral lymphoid tissues. They are endowed of these properties in the process of their interactions with dendritic cells (DCs) that engulf, process, and present antigens to them. Moreover, DCs in dependence of the processed antigens produce different cytokines. If DCs produce IL12, naïve T cells polarise into the T_{H}1 subset, if IL4 into the T_{H}2 subset and eventually, if DCs synthesise IL6, naïve T helper cells will become the T_{H}17 cells. 
