Immobilized MHC class I chain-related protein A synergizes with IL-15 and soluble 4-1BB ligand to expand NK cells with high cytotoxicity ex vivo

Abstract

Major histocompatibility complex (MHC) class I chain-related protein A (MICA), which is a ligand for human NKG2D, is expressed by a variety of epithelial tumor cells and promotes the activation of natural killer (NK), CD8 1 and cd-T cells. Although ectopic expression of MICA on tumor cells elicits anti-tumor responses, soluble MICA downregulates the activities of lymphocytes. In this study, we showed that recombinant, immobilized MICA (iMICA) molecules coated on plastic wells weakly promote peripheral NK cell activation, secretion of interferon (IFN)-c and degranulation without inducing apoptosis. In addition, iMICA synergized with IL-15 and soluble 4-1BB ligand (s4-1BBL) to expand NK cells 25-to 42-fold in a 13-day culture, whereas NK cells stimulated only with IL-15 and s4-1BBL expanded 10-to 16-fold. In contrast to NK cells expanded by IL-15 and s4-1BBL stimulation, NK cells expanded long term in the presence of iMICA exhibited increased cytotoxicity against leukemia cells. These results suggest that large numbers of NK cells with high cytotoxicity can be generated by stimulation with IL-15 and s4-1BBL in the presence of iMICA and that these cells can be used for adoptive cancer immunotherapy. Studies on the 4-1BB signaling pathway have shown that ligation of 4-1BB promotes the survival and multiplication of CD8 1 T and NK cells. 6 IL-15 is essential for the development and function of NK cells. 7 Coculture of NK cells with K562 cells ectopically coexpressing 4-1BB ligand (4-1BBL) and membrane-bound IL-15 effectively promotes the expansion of NK cells in vitro and mediates their cytotoxicity against some leukemia cells. 8,9 In addition, IL-15 upregulates the expression of NKG2D on NK and T cells, even in the presence of soluble NKG2DL. 10 IL-15 and NKG2D signals cross-regulate each other and

Targeting CD137 enhances the efficacy of cetuximab

“…Therefore, as our results demonstrate, anti-CD137 mAb stimulation enhances NK cell-DC crosstalk while also directly enhancing enhanced NK cell function. Our observation is consistent with additional mouse and human studies that report anti-CD137 enhancement of NK cell killing in both hematopoietic and solid tumors lacking expression of the CD137 ligand (33)(34)(35)(36). Rather, by first activating NK cells via CD16 and the Fc-FcγR interaction, surface expression of CD137 is induced and subsequently directly stimulated by administering the agonistic anti-CD137 mAb.…”

“…Although CD137 stimulation has been shown to enhance NK cell function and proliferation in mice (33)(34)(35)(36), a recent study suggests that it may have opposite effects on human NK cells, leading to decreased function, including cytotoxicity (32). This discrepancy with our current results is likely due to differences in experimental conditions.…”

Stimulation of natural killer cells with a CD137-specific antibody enhances trastuzumab efficacy in xenotransplant models of breast cancer

“…We have previously shown that the antilymphoma activity of anti-CD137 agonistic mAb monotherapy requires both CD8 T cells and NK cells (26). Although in the setting of acute myeloid leukemia, expression of CD137 ligand by the leukemic blasts has been shown to impair NK cell spontaneous cytotoxicity (27), additional mouse and human studies have observed enhanced NK cell function, including survival and spontaneous cytotoxicity against both hematopoietic and solid tumors (28)(29)(30)(31). We recently reported that rituximab-induced ADCC of CD20-expressing lymphoma could be augmented by anti-CD137 agonistic mAbs in multiple mouse models (32).…”

Common gamma chain (γc) cytokines differentially potentiate TNFR family signaling in antigen-activated CD8+ T cells

“…Several studies have reported findings that suggest administration of exogenous γc cytokines may augment the efficacy of mAb therapies that target TNFR receptors. Specifically, co-administration of IL-2 has been reported to enhance the anti-tumor immune responses of therapies targeting OX40 (CD134), GITR (CD357) and 4-1BB (CD137) [ 5 ],[ 6 ],[ 61 ],[ 62 ]. In this study, we observed that exposure to IL-2 led recently-activated CD8 + T cells to substantially increase their expression of 4-1BB, GITR, ICOS and OX40, at both the transcriptional and protein level.…”