The present invention pertains to engineered immortalized T-cell lines, method for their preparation and their use as medicament, particularly for immunotherapy. The engineered immortalized T-cell lines of the invention are characterized in that the expression of endogenous T-cell receptors (TCRs) and beta 2-microglobulin (B2M) is inhibited, e.g., by using an endonuclease able to selectively inactivate the TCR and B2M genes in order to render the immortalized T-cells non-alloreactive. In addition, expression of immunosuppressive polypeptide can be performed on those engineered immortalized T-cells in order to prolong the survival of these T-cells in host organisms. Such engineered immortalized T-cells are particularly suitable for allogeneic transplantations, especially because it reduces both the risk of rejection by the host's immune system and the risk of developing graft versus host disease. The invention opens the way to standard and affordable adoptive immunotherapy strategies using immortalized T-cells for treating cancer, infections and auto-immune diseases.
