CRISPR/Cas9-Mediated GFP Reporter Knock-in in K562 and Raji Cell Lines for Tracking Immune Cell Killing Assay.

Cell-mediated cytotoxicity plays an important role in several fundamental immunological processes and is crucial for biological evaluation in in vitro studies. In order to determine the immunological activities of the cells, an assay should be safe, reproducible, and cost-effective. Here, we present a simple and cost-effective approach for evaluation of natural killer (NK) cell-mediated cytotoxicity by generating a CRISPR/Cas9-mediated GFP reporter knock-in in the target cell line, K562, and the non-target cell line, Raji, using a plasmid-based transfection method. The GFP+ target cells facilitate tracking of the immune cell killing assay, which avoids the need for multiple cell labeling with fluorescent dyes. Our approach is also applicable to the genome editing of other target cell types for functional analysis of effector cells.