Activin A backs-up TGF-ß to promote regulatory T cells.

The mechanisms accountable for the infiltration of regulatory T cells into an irradiated tumor remain elusive. In our recent study, we demonstrate that activin A promotes regulatory T cells in tumors, and impairs anti-tumor immune responses induced by radiotherapy and TGF-β blockade. Dual blockade of activin A and TGF-β may be necessary to reduce regulatory T cells mediated immunosuppression driven by radiation therapy.