Figure 12
![Figure 12](http://media.springernature.com/full/springer-static/image/art%3A10.1186%2F1742-4933-10-12/MediaObjects/12979_2012_Article_138_Fig12_HTML.jpg)
T-cell differentiation into functionally different T-cell subsets and age-related defects in T-cell activation. Th1: T helper 1 cells; Th2: T helper 2 cells; Th17: T helper 17 cells; Tbet, GATA3, ROR, FoxP3: different transcriptional factors; IL: interleukin; TGF-β: transforming growth factor beta.