Transfection with mRNA for CD19 specific chimeric antigen receptor restores NK cell mediated killing of CLL cells

An emerging treatment option for chronic lymphocytic leukemia (CLL) is to make cytotoxic immune cells express a chimeric antigen receptor (CAR) that recognizes specific surface molecules on CLL cells. Here an mRNA coding for an anti-CD19 CAR was transfected into the NK-92 cell line by electroporation. In contrast to cDNA, mRNA resulted in high transfection efficiency (47.2 +/- 8% versus <5% for cDNA) with minimal effect on cell viability. NK-92 cells expressing anti-CD19 CAR killed previously resistant CD19+ B-ALL cell lines, as well as primary CLL cells and therefore may present a safe, cell-based, targeted treatment for patients with CLL.