Effects of different serum supplements on PiggyBac CD19 Chimeric Antigen Receptor T cells

Abstract

Chimeric Antigen Receptor (CAR) T cell is a novel therapy for relapse and refractory hematologic malignancy. Characteristics of CAR T cells is associated with clinical efficacy and toxicity. Type of serum supplements used during cultivation affect the immunophenotype and function of viral-based CAR T cells. This study explores the effect of serum supplements on non-viral piggyBac transposon CAR T cell production. PiggyBac CD19 CAR T cells were expanded in cultured conditions containing either fetal bovine serum, human AB serum, human platelet lysate or xeno-free serum replacement. Then, the effect of different serum supplements on cell expansion, transfection efficiency, immunophenotypes and anti-tumor activity were evaluated. Xeno-free serum replacement exhibited comparable CAR surface expression, cell expansion, and short-term anti-tumor activity comparing with conventional serum supplements. However, CAR T cell cultivated with xeno-free and serum-free cultured condition exhibited increase naïve T cell population and better T cell expansion after long term co-culture as well as during tumor rechallenge assay. This study supports the usage of xeno-free serum replacement as an alternative source of serum supplements for PiggyBac based CAR T cell expansion.