A novel GPI-anchored dominant-negative TGF-j3 receptor II renders T cells unresponsive to TGF-j3 signaling

Transforming growth factor O (TGF-O) is a pleiotropic cyto-kine expressed by a wide range of cell types and is known for hampering the effectiveness of cancer immune cell therapeutic approaches. We have designed a novel construct containing the extracellular domain of the TGF-O receptor II linked to a gly-cosylphosphatidylinositol (GPI) anchor (GPI-ecto-TORII) lacking the transmembrane and cytoplasmic signaling domain of TGF-O receptor II (TORII). T cells transduced with lenti -virus expressing the GPI-ecto-TORII construct show 5 to 15 times higher membrane expression compared with a previously established dominant-negative receptor carrying a truncated signaling domain. GPI-ecto-TORII expression renders T cells unresponsive to TGF-O-induced signaling seen by a lack of SMAD phosphorylation upon exogeneous TGF-O treatment. Transduced T cells continue to express high levels of IFNy and granulocyte-macrophage colony-stimulating factor (GM-CSF), among other cytokines, in the presence of TGF-O while cytokine expression in untransduced T cells is being markedly suppressed. Furthermore, T cells expressing GPI-ecto-TORII constructs have been shown to efficiently capture and inactivate TGF-O from their environment. These results indicate the po-tential benefits of GPI-ecto-TORII expressing cytotoxic T cells (CTLs) in future cell therapies.