Immune-mediated eradication of tumors through the blockade of transforming growth factor-β signaling in T cells

Despite the existence of tumor-specific antigens and demonstrated presence of tumor-specific immune cells, the majority of tumors manage to avoid immune-mediated destruction. Various mechanisms have been suggested for tumor evasion from immune response. One such mechanism is thought to be mediated by transforming growth factor-beta (TGF-beta), an immunosuppressive cytokine found at the site of most tumors. We demonstrate here that T-cell-specific blockade of TGF-beta signaling allows the generation of an immune response capable of eradicating tumors in mice challenged with live tumor cells. In addition, we provide mechanisms through which abrogation of TGF-beta signaling leads to the enhancement of anti-tumor immunity. Our data indicate that T-cell-specific blockade of TGF-beta signaling has strong therapeutic potential to shift the balance of the immune response in favor of anti-tumor immunity.