Low interleukin-2 concentration favors generation of early memory T cells over effector phenotypes during chimeric antigen receptor T-cell expansion
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CitationKaartinen T. Luostarinen A. Maliniemi P. Keto J. Arvas M. Belt H. Koponen J. Loskog A. Mustjoki S. Porkka K. Ylä-Herttuala S. Korhonen M. (2017). Low interleukin-2 concentration favors generation of early memory T cells over effector phenotypes during chimeric antigen receptor T-cell expansion. Cytotherapy, 19 (6) , 689-702. 10.1016/j.jcyt.2017.03.067.
Adoptive T-cell therapy offers new options for cancer treatment. Clinical results suggest that T-cell persistence, depending on T-cell memory, improves efficacy. The use of interleukin (IL)-2 for in vitro T-cell expansion is not straightforward because it drives effector T-cell differentiation but does not promote the formation of T-cell memory. We have developed a cost-effective expansion protocol for chimeric antigen receptor (CAR) T cells with an early memory phenotype.
Lymphocytes were transduced with third-generation lentiviral vectors and expanded using CD3/CD28 microbeads. The effects of altering the IL-2 supplementation (0–300 IU/mL) and length of expansion (10–20 days) on the phenotype of the T-cell products were analyzed.
High IL-2 levels led to a decrease in overall generation of early memory T cells by both decreasing central memory T cells and augmenting effectors. T memory stem cells (TSCM, CD95+CD45RO−CD45RA+CD27+) were present variably during T-cell expansion. However, their presence was not IL-2 dependent but was linked to expansion kinetics. CD19-CAR T cells generated in these conditions displayed in vitro antileukemic activity. In summary, production of CAR T cells without any cytokine supplementation yielded the highest proportion of early memory T cells, provided a 10-fold cell expansion and the cells were functionally potent.
The number of early memory T cells in a T-cell preparation can be increased by simply reducing the amount of IL-2 and limiting the length of T-cell expansion, providing cells with potentially higher in vivo performance. These findings are significant for robust and cost-effective T-cell manufacturing.