Ex vivo expansion, maturation, and activation of umbilical cord blood–derived T lymphocytes with IL-2, IL-12, anti-CD3, and IL-7: Potential for adoptive cellular immunotherapy post–umbilical cord blood transplantation

Objectives We investigated whether umbilical cord blood (UCB) T cells could be ex vivo expanded and activated in short-term culture for potential utilization as adoptive cellular immunotherapy post–umbilical cord blood transplantation (UCBT). Methods Fresh UCB mononuclear cells (MNCs) were isolated by Ficoll density centrifugation. Cryopreserved UCB mononuclear cells were thawed and washed with 2.5% human serum albumin and 5% dextrose in isotonic saline. The nonadherent MNC fraction were then plated in a serum-free cocktail of IL-2, IL-12, and anti-CD3 with and without IL-7 for 48 hours. Proliferation, cytotoxicity, TH1 (IFN-γ), CD25, and CD45RO assays were performed. Results Proliferation studies demonstrated a significant increase in the proliferative ability of the UCB MNCs incubated in anti-CD3, IL-2, IL-12, and IL-7 (fresh—p < 0.005, and thawed—p < 0.001). The combination of all four agonists significantly induced expression of CD45 RO (fresh—p < 0.05, and thawed—p < 0.001) in both the CD4+ and CD8+ T cells expressing CD25 (fresh UCB—p < 0.01 [CD4] and p < 0.005 [CD8], respectively; thawed UCB—p < 0.001 [CD4] and p < 0.001 [CD8]). Intracellular cytokine profiles also revealed a significant increase in the production of IFN-γ (TH1 cells) (fresh UCB—p < 0.005, and thawed UCB—p < 0.001). The combination also significantly increased the killing of K562-labeled target cells (fresh—p < 0.0001, and thawed—0.731 ± 0.03 vs 0.16 ± 0.01) (p < 0.001). Conclusion These data suggest that the ex vivo combination of IL-2, IL-12, anti-CD3, and IL-7 significantly enhances the proliferation, activation, maturation, and cytotoxic potential of UCB T cells of both fresh and thawed UCB MNC. Further studies, however, are required to determine whether these ex vivo–expanded MNC could also potentially exacerbate acute or chronic graft-vs-host disease and/or other toxicities if utilized post-UCBT.