T Cell Engineering.

T cells are a new and promising antigen-specific therapeutic option for the treatment of malignant diseases. To achieve antigen specificity against tumor antigens, T cells can be manipulated by gene transfer to express chimeric antigen receptors (CARs). CAR-expressing T cells are called redirected T cells. CARs are composed of an extracellular antibody-derived antigen recognition domain, a transmembrane domain and a cytoplasmatic signal domain. Therefore, redirected T cells combine the exchangeable specificity of an antibody with the cytotoxic machinery of a T cell. Early clinical trials with redirected T cells targeting cluster of differentiation (CD) 19 have shown impressive results in CD19-positive hematological cancers. However, for solid cancers only limited clinical experience exists and new and innovative concepts have to be developed to overcome tumor-mediated immune suppression. Herein, we describe the general design of a CAR, the function of the different domains and the different strategies to produce redirected T cells. Furthermore, we summarize and discuss the preclinical and clinical data indicating the tremendous potential of redirected T cells to become a mainstay of cancer immunotherapy.