Higher yields of Vγ9Vδ2 T cells from peripheral blood than umbilical cord blood via interleukin-12 and interleukin-18.

PURPOSE: To evaluate the efficacy of a modified protocol involving interleukin-12 (IL-12) and IL-18 in the ex vivo expansion of Vγ9Vδ2 T cells (a major subset of γδ T cells, referred to as GDTs) and to compare the expansion efficiency and functional activity of these cells when peripheral blood (PB) and umbilical cord blood (UCB) were used as cell sources.

METHODS

Mononuclear cells obtained from PB and UCB were cultured with zoledronic acid and IL-2 for 15 days. IL-12 was added from days 9-15 and IL-18 was added from days 12-15 to generate advanced GDTs (adGDTs). These adGDTs were compared to conventional GDTs (produced without cytokine supplementation). Expanded cells were then evaluated in terms of phenotype and function, including cytotoxic activity and antigen-presenting capacity. Lastly, associations between baseline lineage composition, including BTN2A1-positive subsets, and GDT yield from UCB were analyzed.

RESULTS

In PB-derived cultures, IL-12 and IL-18 supplementation significantly increased GDT cytotoxic activity while maintaining antigen-presenting capacity. With the same protocol, UCB-derived cultures had significantly lower and more variable GDT yields compared with PB-derived cultures (28.13% ± 24.79% versus 54.78% ± 7.73%, P = 0.0007). In the UCB samples, adGDT yield was positively correlated with HLA-DR-positive monocytes (r = 0.7857) and T cells (r = 0.7381) but inversely correlated with the proportions of BTN2A1-positive monocytes (r = -0.6429) and T cells (r = -0.5357).

CONCLUSION

IL-12 and IL-18 supplementation generates adGDTs with augmented cytotoxicity without compromising antigen-presenting capacity. PB is a more reliable cell source than is UCB for clinical-scale GDT expansion, and it results in higher and more uniform output under the same protocol.