Cancer immunotherapies focus on the power of the immune system to attack tumor cells. Recently, Chimeric Antigen Receptors expressing T cells (CAR-T cells) have received clinical approval for antigen-specific adoptive immunotherapy against CD19 in B cell malignancies. CAR vector designs have dramatically developed since their initial discovery and now include first-generation CARs (CD3ζ-based CAR), second-generation CARs with additional costimulatory domains such as CD28 or CD137 and third generation CARs (CD3ζ with two costimulatory domains) and recently fourth generation CAR with a transgene for cytokine stimulation. Natural Killer (NK) cells have ability recognize the tumor cells by their native receptors and have grown to be promising candidates for adoptive immunotherapy of cancer. CAR expression in NK cells is also clinically tested and carries the potential to translate into clinical application but the majority of literature on CAR vector design relies on observations from T cells. This thesis aims to use NK-92 cells for evaluation of different designs in order to optimize a CAR vector that could be efficiently used to retarget NK cells against tumor antigens. CAR transgenes comprising identical antigen binding domains that target CD19, combined with different intracellular signaling domains (CD3ζ , CD28 and CD137) are transferred to NK-92 cells via the use of lentiviral vectors. Cytotoxic activity and antigen-specificity of CAR-NK-92 cells are evaluated against the CD19- classical NK cell target K562 cell line and the CD19+ cell line Daudi and Namalwa by analysis of degranulation and cytokine secretion. Our results provide valuable data for optimal CAR vector design in NK cell
