Media evaluation for production and expansion of anti-CD19 chimeric antigen receptor T cells.

BACKGROUND: The use of CD19 chimeric antigen receptor (CAR) T cells to treat B-cell malignancies has proven beneficial. Several groups use serum to produce CD19 CAR T cells. Today, ready-to-use serum-free media that require no addition of serum are commercially available. Therefore, it becomes important to evaluate the production of CD19 CAR T cells with and without the addition of serum.

METHODS: T cells from buffy coats were cultured in AIM-V and TexMACS (TM) supplemented with 5% human serum (A5% and TM5%, respectively), and in TM without serum. Cells were activated with OKT3 and expanded in interleukin (IL)-2. Viral transduction was performed in RetroNectin-coated plates using the spinoculation method. CD19 CAR T cells were tested for their viability, expansion, transduction efficacy, phenotype and cytotoxicity.

RESULTS: CD19 CAR T cells expanded in A5% and TM5% showed significantly better viability and higher fold expansion than cells expanded in TM. TM promoted the expansion of CD8+ T cells and effector phenotype of CD19 CAR T cells. The transduction efficacy and the cytotoxic function were comparable between the different media. Higher CD107a+ cells were detected in TM and TM5%, whereas higher IL-2+ and IL-17+ cells were detected in A5%. CD19 CAR exhibited co-expression of inhibitory receptors such as TIM-3+ LAG-3+ and/or TIM-3+ PD-1+ .

CONCLUSION: Our results indicate that serum supplementation promotes better CD19 CAR T-cell expansion and viability in vitro. CD19 CAR T cells produced in TM medium showed lower CD4/CD8 ratio, which warrants further evaluation in clinical settings. Overall, the choice of culture medium impacts CD19 CAR T-cell end product.