Figure 2: T-cells regulate fibrosis through direct and indirect mechanisms.
CD4+ T-cells produce multiple factors that influence macrophage (M1 versus M2) polarization which in turn influence fibroblast activity and fibrotic deposition of collagen. T-reg cells influence fibroblast activity through direct cellular interaction in tissues. CD8+ cells are critical at early and late times after ischemic injury. T-cell activity with known age-dependent changes in activity are shown in purple. IL- interleukin; TGFβ- tissue growth factor β.