Lower concentrations of methyl-β-cyclodextrin combined with interleukin-2 can preferentially induce activation and proliferation of natural killer cells in human peripheral blood

Abstract

Previous studies have demonstrated that high concentrations of methyl-β-cyclodextrin (MβCD, 10–15 mM) can interfere with the formation of lipid rafts and inhibit activation of lymphocytes. In this report, we determined that lower concentrations of MβCD (1–4 mM) could accelerate the proliferation of lymphocytes in human peripheral blood mononuclear cells (PBMCs). In the expanded cells, CD3 -CD56 + natural killer (NK) cells were the dominant subpopulation, and a significant dose–effect relationship existed between the proportion of NK cells and the concentration of MβCD. In the groups treated with 3–4 mM MβCD, the proportions of NK cells reached a level of more than 60%. When PBMCs were treated with MβCD, CD69 was more preferentially expressed on CD3 -CD56 + cells than on CD3 + cells at 48 and 72 hours. The expression of CD25 had no distinct difference at 48 hours, but when recombinant human interleukin-2 (IL-2) was added for a further 24 hours, it was also preferentially expressed on NK cells. MβCD and IL-2 synergistically could also induce interferon-γ (IFN-γ) production in CD56 + human PBMCs. Mechanistic studies revealed that IFN-γ production in response to MβCD plus IL-2 was IL-12 independent but depended on endogenous IL-18 and IL-1β, and CD56 +CD14 + dendritic cell-like cells and B cells might mediate the ability of MβCD to activate NK cells. The MβCD-activated NK cells also had high cytotoxicity against the natural killer cell–sensitive K562 cells or lymphokine-activated killer cell–sensitive DAUDI cells in vitro. These studies indicated that lower concentrations of MβCD combined with IL-2 can preferentially induce activation and proliferation of NK cells in PBMCs.