piggyBac Transposon/Transposase System to Generate CD19-Specific T Cells for the Treatment of B-Lineage Malignancies

In this report, transposition with the piggyBac system is used to introduce a chimeric antigen receptor (CAR) into T lymphocytes. The CD19-specific CAR is expressed long term in expanding T cell populations from its integrated locus and leads to CD19-dependent killing of tumor targets. Chromosomal analysis indicated no signs of genotoxicity. Nonviral integrating vectors can be used for expression of therapeutic genes. piggyBac (PB), a transposon/transposase system, has been used to efficiently generate induced pluripotent stems cells from somatic cells, without genetic alteration. In this paper, we apply PB transposition to express a chimeric antigen receptor (CAR) in primary human T cells. We demonstrate that T cells electroporated to introduce the PB transposon and transposase stably express CD19-specific CAR and when cultured on CD19+ artificial antigen-presenting cells, numerically expand in a CAR-dependent manner, display a phenotype associated with both memory and effector T cell populations, and exhibit CD19-dependent killing of tumor targets. Integration of the PB transposon expressing CAR was not associated with genotoxicity, based on chromosome analysis. PB transposition for generating human T cells with redirected specificity to a desired target such as CD19 is a new genetic approach with therapeutic implications.