Skip to main content

NK Cell and NKT Cell Immunotherapy

  • Chapter
  • First Online:
Immunotherapy for Pediatric Malignancies

Abstract

NK cells are a vital component of our innate immune system and serve a variety of biologic functions, including the eradication of tumor. Their importance in preventing leukemic relapse after stem cell transplantation is well documented. The cytotoxic activity of NK cells is regulated by activating and inhibitory signals resulting from interactions between their cell surface receptors and ligands expressed on potential targets. NK cells may destroy tumors directly, or may participate in antibody dependent cellular cytotoxicity (ADCC). The function of NK cells can be augmented by the use of drugs, cytokines, or through genetic modifications. NK cells may also be expanded, ex vivo, for use in adoptive immunotherapy. NKT cells possess features of both the innate and adaptive immune system, and express an invariant T cell receptor (iNKT cells) that recognizes glycolipid antigens in the context of the MHC class-I-like CD1d molecule. iNKT cells are also being utilized for cancer immunotherapy.

This is a preview of subscription content, log in via an institution to check access.

Access this chapter

eBook
USD 16.99
Price excludes VAT (USA)
  • Available as EPUB and PDF
  • Read on any device
  • Instant download
  • Own it forever
Softcover Book
USD 129.99
Price excludes VAT (USA)
  • Compact, lightweight edition
  • Dispatched in 3 to 5 business days
  • Free shipping worldwide - see info
Hardcover Book
USD 179.99
Price excludes VAT (USA)
  • Durable hardcover edition
  • Dispatched in 3 to 5 business days
  • Free shipping worldwide - see info

Tax calculation will be finalised at checkout

Purchases are for personal use only

Institutional subscriptions

References

  1. Yu J, Freud AG, Caligiuri MA. Location and cellular stages of natural killer cell development. Trends Immunol. 2013;34:573–82.

    Article  CAS  PubMed  Google Scholar 

  2. Campbell JJ, Qin S, Unutmaz D, et al. Unique subpopulations of CD56+ NK and NK-T peripheral blood lymphocytes identified by chemokine receptor expression repertoire. J Immunol. 2001;166:6477–82.

    Article  CAS  PubMed  Google Scholar 

  3. Caligiuri MA. Human natural killer cells. Blood. 2008;112:461–9.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  4. Strowig T, Brilot F, Munz C. Noncytotoxic functions of NK cells: direct pathogen restriction and assistance to adaptive immunity. J Immunol. 2008;180:7785–91.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  5. De Maria A, Bozzano F, Cantoni C, Moretta L. Revisiting human natural killer cell subset function revealed cytolytic CD56(dim)CD16+ NK cells as rapid producers of abundant IFN-gamma on activation. Proc Natl Acad Sci U S A. 2011;108:728–32.

    Article  PubMed  Google Scholar 

  6. Walzer T, Dalod M, Robbins SH, Zitvogel L, Vivier E. Natural-killer cells and dendritic cells: "l'union fait la force". Blood. 2005;106:2252–8.

    Article  CAS  PubMed  Google Scholar 

  7. Orange JS. Formation and function of the lytic NK-cell immunological synapse. Nat Rev Immunol. 2008;8:713–25.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  8. Chowdhury D, Lieberman J. Death by a thousand cuts: granzyme pathways of programmed cell death. Annu Rev Immunol. 2008;26:389–420.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  9. Lieberman J. Mechanisms of granule-mediated cytotoxicity. Curr Opin Immunol. 2003;15:513–5.

    Article  CAS  Google Scholar 

  10. Chavez-Galan L, Arenas-Del Angel MC, Zenteno E, Chavez R, Lascurain R. Cell death mechanisms induced by cytotoxic lymphocytes. Cell Mol Immunol. 2009;6:15–25.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  11. Strasser A, Jost PJ, Nagata S. The many roles of FAS receptor signaling in the immune system. Immunity. 2009;30:180–92.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  12. Brandt CS, Baratin M, Yi EC, et al. The B7 family member B7-H6 is a tumor cell ligand for the activating natural killer cell receptor NKp30 in humans. J Exp Med. 2009;206:1495–503.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  13. Semeraro M, Rusakiewicz S, Minard-Colin V, et al. Clinical impact of the NKp30/B7-H6 axis in high-risk neuroblastoma patients. Sci Transl Med. 2015;7:283ra255.

    Article  CAS  Google Scholar 

  14. Glasner A, Ghadially H, Gur C, et al. Recognition and prevention of tumor metastasis by the NK receptor NKp46/NCR1. J Immunol. 2012;188:2509–15.

    Article  CAS  PubMed  Google Scholar 

  15. Horton NC, Mathew PA. NKp44 and natural cytotoxicity receptors as damage-associated molecular pattern recognition receptors. Front Immunol. 2015;6:31.

    Article  PubMed  PubMed Central  CAS  Google Scholar 

  16. Castriconi R, Dondero A, Corrias MV, et al. Natural killer cell-mediated killing of freshly isolated neuroblastoma cells: critical role of DNAX accessory molecule-1-poliovirus receptor interaction. Cancer Res. 2004;64:9180–4.

    Article  CAS  PubMed  Google Scholar 

  17. Gilfillan S, Chan CJ, Cella M, et al. DNAM-1 promotes activation of cytotoxic lymphocytes by nonprofessional antigen-presenting cells and tumors. J Exp Med. 2008;205:2965–73.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  18. Lakshmikanth T, Burke S, Ali TH, et al. NCRs and DNAM-1 mediate NK cell recognition and lysis of human and mouse melanoma cell lines in vitro and in vivo. J Clin Invest. 2009;119:1251–63.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  19. Cooley S, Trachtenberg E, Bergemann TL, et al. Donors with group B KIR haplotypes improve relapse-free survival after unrelated hematopoietic cell transplantation for acute myelogenous leukemia. Blood. 2009;113:726–32.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  20. Pende D, Marcenaro S, Falco M, et al. Anti-leukemia activity of alloreactive NK cells in KIR ligand-mismatched haploidentical HSCT for pediatric patients: evaluation of the functional role of activating KIR and redefinition of inhibitory KIR specificity. Blood. 2009;113:3119–29.

    Article  CAS  PubMed  Google Scholar 

  21. Venstrom JM, Pittari G, Gooley TA, et al. HLA-C-dependent prevention of leukemia relapse by donor activating KIR2DS1. N Engl J Med. 2012;367:805–16.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  22. Chitadze G, Bhat J, Lettau M, Janssen O, Kabelitz D. Generation of soluble NKG2D ligands: proteolytic cleavage, exosome secretion and functional implications. Scand J Immunol. 2013;78:120–9.

    Article  CAS  PubMed  Google Scholar 

  23. Kim S, Poursine-Laurent J, Truscott SM, et al. Licensing of natural killer cells by host major histocompatibility complex class I molecules. Nature. 2005;436:709–13.

    Article  CAS  PubMed  Google Scholar 

  24. Orr MT, Lanier LL. Natural killer cell education and tolerance. Cell. 2010;142:847–56.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  25. Berghuis D, de Hooge AS, Santos SJ, et al. Reduced human leukocyte antigen expression in advanced-stage Ewing sarcoma: implications for immune recognition. J Pathol. 2009;218:222–31.

    Article  CAS  PubMed  Google Scholar 

  26. Borowski A, van Valen F, Ulbrecht M, et al. Monomorphic HLA class I-(non-A, non-B) expression on Ewing's tumor cell lines, modulation by TNF-alpha and IFN-gamma. Immunobiology. 1999;200:1–20.

    Article  CAS  PubMed  Google Scholar 

  27. Mechtersheimer G, Staudter M, Majdic O, Dorken B, Moldenhauer G, Moller P. Expression of HLA-A,B,C, beta 2-microglobulin (beta 2m), HLA-DR, -DP, -DQ and of HLA-D-associated invariant chain (Ii) in soft-tissue tumors. Int J Cancer. 1990;46:813–23.

    Article  CAS  PubMed  Google Scholar 

  28. Peters HL, Yan Y, Solheim JC. APLP2 regulates the expression of MHC class I molecules on irradiated Ewing’s sarcoma cells. Oncoimmunology. 2013;2:e26293.

    Article  PubMed  PubMed Central  Google Scholar 

  29. Ruggeri L, Capanni M, Urbani E, et al. Effectiveness of donor natural killer cell alloreactivity in mismatched hematopoietic transplants. Science. 2002;295:2097–100.

    Article  CAS  PubMed  Google Scholar 

  30. Leung W, Iyengar R, Turner V, et al. Determinants of antileukemia effects of allogeneic NK cells. J Immunol. 2004;172:644–50.

    Article  CAS  PubMed  Google Scholar 

  31. Cooley S, Weisdorf DJ, Guethlein LA, et al. Donor killer cell Ig-like receptor B haplotypes, recipient HLA-C1, and HLA-C mismatch enhance the clinical benefit of unrelated transplantation for acute myelogenous leukemia. J Immunol. 2014;192:4592–600.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  32. Giebel S, Locatelli F, Lamparelli T, et al. Survival advantage with KIR ligand incompatibility in hematopoietic stem cell transplantation from unrelated donors. Blood. 2003;102:814–9.

    Article  CAS  PubMed  Google Scholar 

  33. Hsu KC, Keever-Taylor CA, Wilton A, et al. Improved outcome in HLA-identical sibling hematopoietic stem-cell transplantation for acute myelogenous leukemia predicted by KIR and HLA genotypes. Blood. 2005;105:4878–84.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  34. Symons HJ, Leffell MS, Rossiter ND, Zahurak M, Jones RJ, Fuchs EJ. Improved survival with inhibitory killer immunoglobulin receptor (KIR) gene mismatches and KIR haplotype B donors after nonmyeloablative, HLA-haploidentical bone marrow transplantation. Biol Blood Marrow Transplant. 2010;16:533–42.

    Article  PubMed  Google Scholar 

  35. Venstrom JM, Zheng J, Noor N, et al. KIR and HLA genotypes are associated with disease progression and survival following autologous hematopoietic stem cell transplantation for high-risk neuroblastoma. Clin Cancer Res. 2009;15:7330–4.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  36. Delgado DC, Hank JA, Kolesar J, et al. Genotypes of NK cell KIR receptors, their ligands, and Fcgamma receptors in the response of neuroblastoma patients to Hu14.18-IL2 immunotherapy. Cancer Res. 2010;70:9554–61.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  37. Berg M, Lundqvist A, McCoy P Jr, et al. Clinical-grade ex vivo-expanded human natural killer cells up-regulate activating receptors and death receptor ligands and have enhanced cytolytic activity against tumor cells. Cytotherapy. 2009;11:341–55.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  38. Denman CJ, Senyukov VV, Somanchi SS, et al. Membrane-bound IL-21 promotes sustained ex vivo proliferation of human natural killer cells. PLoS One. 2012;7:e30264.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  39. Fujisaki H, Kakuda H, Shimasaki N, et al. Expansion of highly cytotoxic human natural killer cells for cancer cell therapy. Cancer Res. 2009;69:4010–7.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  40. Iliopoulou EG, Kountourakis P, Karamouzis MV, et al. A phase I trial of adoptive transfer of allogeneic natural killer cells in patients with advanced non-small cell lung cancer. Cancer Immunol Immunother. 2010;59:1781–9.

    Article  PubMed  Google Scholar 

  41. Koehl U, Brehm C, Huenecke S, et al. Clinical grade purification and expansion of NK cell products for an optimized manufacturing protocol. Front Oncol. 2013;3:118.

    Article  PubMed  PubMed Central  Google Scholar 

  42. Lim SA, Kim TJ, Lee JE, et al. Ex vivo expansion of highly cytotoxic human NK cells by cocultivation with irradiated tumor cells for adoptive immunotherapy. Cancer Res. 2013;73:2598–607.

    Article  CAS  PubMed  Google Scholar 

  43. Somanchi SS, Senyukov VV, Denman CJ, Lee DA. Expansion, purification, and functional assessment of human peripheral blood NK cells. J Vis Exp. 2011;48:2540.

    Google Scholar 

  44. Granzin M, Soltenborn S, Muller S, et al. Fully automated expansion and activation of clinical-grade natural killer cells for adoptive immunotherapy. Cytotherapy. 2015;17:621–32.

    Article  CAS  PubMed  Google Scholar 

  45. Garg TK, Szmania SM, Khan JA, et al. Highly activated and expanded natural killer cells for multiple myeloma immunotherapy. Haematologica. 2012;97:1348–56.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  46. Rujkijyanont P, Chan WK, Eldridge PW, et al. Ex vivo activation of CD56+ immune cells that eradicate neuroblastoma. Cancer Res. 2013;73:2608–18.

    Article  CAS  PubMed  Google Scholar 

  47. Zhang H, Cui Y, Voong N, et al. Activating signals dominate inhibitory signals in CD137L/IL-15 activated natural killer cells. J Immunother. 2011;34:187–95.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  48. Cho D, Shook DR, Shimasaki N, Chang YH, Fujisaki H, Campana D. Cytotoxicity of activated natural killer cells against pediatric solid tumors. Clin Cancer Res. 2010;16:3901–9.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  49. Voskens CJ, Watanabe R, Rollins S, Campana D, Hasumi K, Mann DL. Ex-vivo expanded human NK cells express activating receptors that mediate cytotoxicity of allogeneic and autologous cancer cell lines by direct recognition and antibody directed cellular cytotoxicity. J Exp Clin Cancer Res. 2010;29:134.

    Article  PubMed  PubMed Central  CAS  Google Scholar 

  50. Spanholtz J, Tordoir M, Eissens D, et al. High log-scale expansion of functional human natural killer cells from umbilical cord blood CD34-positive cells for adoptive cancer immunotherapy. PLoS One. 2010;5:e9221.

    Article  PubMed  PubMed Central  CAS  Google Scholar 

  51. Grzywacz B, Kataria N, Sikora M, et al. Coordinated acquisition of inhibitory and activating receptors and functional properties by developing human natural killer cells. Blood. 2006;108:3824–33.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  52. Woll PS, Grzywacz B, Tian X, et al. Human embryonic stem cells differentiate into a homogeneous population of natural killer cells with potent in vivo antitumor activity. Blood. 2009;113:6094–101.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  53. Knorr DA, Ni Z, Hermanson D, et al. Clinical-scale derivation of natural killer cells from human pluripotent stem cells for cancer therapy. Stem Cells Transl Med. 2013;2:274–83.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  54. Rezvani K, Rouce RH. The application of natural killer cell immunotherapy for the treatment of cancer. Front Immunol. 2015;6:578.

    Article  PubMed  PubMed Central  CAS  Google Scholar 

  55. Gong JH, Maki G, Klingemann HG. Characterization of a human cell line (NK-92) with phenotypical and functional characteristics of activated natural killer cells. Leukemia. 1994;8:652–8.

    CAS  PubMed  Google Scholar 

  56. Tam YK, Miyagawa B, Ho VC, Klingemann HG. Immunotherapy of malignant melanoma in a SCID mouse model using the highly cytotoxic natural killer cell line NK-92. J Hematother. 1999;8:281–90.

    Article  CAS  PubMed  Google Scholar 

  57. Yan Y, Steinherz P, Klingemann HG, et al. Antileukemia activity of a natural killer cell line against human leukemias. Clin Cancer Res. 1998;4:2859–68.

    CAS  PubMed  Google Scholar 

  58. Maki G, Klingemann HG, Martinson JA, Tam YK. Factors regulating the cytotoxic activity of the human natural killer cell line, NK-92. J Hematother Stem Cell Res. 2001;10:369–83.

    Article  CAS  PubMed  Google Scholar 

  59. Tam YK, Martinson JA, Doligosa K, Klingemann HG. Ex vivo expansion of the highly cytotoxic human natural killer-92 cell-line under current good manufacturing practice conditions for clinical adoptive cellular immunotherapy. Cytotherapy. 2003;5:259–72.

    Article  CAS  PubMed  Google Scholar 

  60. Becknell B, Caligiuri MA. Interleukin-2, interleukin-15, and their roles in human natural killer cells. Adv Immunol. 2005;86:209–39.

    Article  CAS  PubMed  Google Scholar 

  61. Ferlazzo G, Pack M, Thomas D, et al. Distinct roles of IL-12 and IL-15 in human natural killer cell activation by dendritic cells from secondary lymphoid organs. Proc Natl Acad Sci U S A. 2004;101:16606–11.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  62. Konjevic G, Mirjacic Martinovic K, Vuletic A, Babovic N. In-vitro IL-2 or IFN-alpha-induced NKG2D and CD161 NK cell receptor expression indicates novel aspects of NK cell activation in metastatic melanoma patients. Melanoma Res. 2010;20:459–67.

    Article  CAS  PubMed  Google Scholar 

  63. Hromadnikova I, Pirkova P, Sedlackova L. Influence of in vitro IL-2 or IL-15 alone or in combination with Hsp-70-derived 14-mer peptide (TKD) on the expression of NK cell activatory and inhibitory receptors. Mediat Inflamm. 2013;2013:405295.

    Google Scholar 

  64. Vitale M, Bottino C, Sivori S, et al. NKp44, a novel triggering surface molecule specifically expressed by activated natural killer cells, is involved in non-major histocompatibility complex-restricted tumor cell lysis. J Exp Med. 1998;187:2065–72.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  65. Yakes FM, Chinratanalab W, Ritter CA, King W, Seelig S, Arteaga CL. Herceptin-induced inhibition of phosphatidylinositol-3 kinase and Akt Is required for antibody-mediated effects on p 27, cyclin D1, and antitumor action. Cancer Res. 2002;62:4132–41.

    CAS  PubMed  Google Scholar 

  66. Skak K, Frederiksen KS, Lundsgaard D. Interleukin-21 activates human natural killer cells and modulates their surface receptor expression. Immunology. 2008;123:575–83.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  67. Trotta R, Ciarlariello D, Dal Col J, et al. The PP2A inhibitor SET regulates granzyme B expression in human natural killer cells. Blood. 2011;117:2378–84.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  68. Handa K, Suzuki R, Matsui H, Shimizu Y, Kumagai K. Natural killer (NK) cells as a responder to interleukin 2 (IL 2). II. IL 2-induced interferon gamma production. J Immunol. 1983;130:988–92.

    CAS  PubMed  Google Scholar 

  69. Hank JA, Kohler PC, Weil-Hillman G, et al. In vivo induction of the lymphokine-activated killer phenomenon: interleukin 2-dependent human non-major histocompatibility complex-restricted cytotoxicity generated in vivo during administration of human recombinant interleukin 2. Cancer Res. 1988;48:1965–71.

    CAS  PubMed  Google Scholar 

  70. He XS, Draghi M, Mahmood K, et al. T cell-dependent production of IFN-gamma by NK cells in response to influenza A virus. J Clin Invest. 2004;114:1812–9.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  71. Meropol NJ, Porter M, Blumenson LE, et al. Daily subcutaneous injection of low-dose interleukin 2 expands natural killer cells in vivo without significant toxicity. Clin Cancer Res. 1996;2:669–77.

    CAS  PubMed  Google Scholar 

  72. Miller JS, Tessmer-Tuck J, Pierson BA, et al. Low dose subcutaneous interleukin-2 after autologous transplantation generates sustained in vivo natural killer cell activity. Biol Blood Marrow Transplant. 1997;3:34–44.

    CAS  PubMed  Google Scholar 

  73. Siegel JP, Sharon M, Smith PL, Leonard WJ. The IL-2 receptor beta chain (p 70): role in mediating signals for LAK, NK, and proliferative activities. Science. 1987;238:75–8.

    Article  CAS  PubMed  Google Scholar 

  74. Sondel PM, Kohler PC, Hank JA, et al. Clinical and immunological effects of recombinant interleukin 2 given by repetitive weekly cycles to patients with cancer. Cancer Res. 1988;48:2561–7.

    CAS  PubMed  Google Scholar 

  75. Trinchieri G, Matsumoto-Kobayashi M, Clark SC, Seehra J, London L, Perussia B. Response of resting human peripheral blood natural killer cells to interleukin 2. J Exp Med. 1984;160:1147–69.

    Article  CAS  PubMed  Google Scholar 

  76. Weil-Hillman G, Fisch P, Prieve AF, Sosman JA, Hank JA, Sondel PM. Lymphokine-activated killer activity induced by in vivo interleukin 2 therapy: predominant role for lymphocytes with increased expression of CD2 and leu 19 antigens but negative expression of CD16 antigens. Cancer Res. 1989;49:3680–8.

    CAS  PubMed  Google Scholar 

  77. Rosenberg SA, Lotze MT, Muul LM, et al. Observations on the systemic administration of autologous lymphokine-activated killer cells and recombinant interleukin-2 to patients with metastatic cancer. N Engl J Med. 1985;313:1485–92.

    Article  CAS  PubMed  Google Scholar 

  78. Bauer M, Reaman GH, Hank JA, et al. A phase II trial of human recombinant interleukin-2 administered as a 4-day continuous infusion for children with refractory neuroblastoma, non-Hodgkin's lymphoma, sarcoma, renal cell carcinoma, and malignant melanoma. A childrens cancer group study. Cancer. 1995;75:2959–65.

    Article  CAS  PubMed  Google Scholar 

  79. Lange BJ, Yang RK, Gan J, et al. Soluble interleukin-2 receptor alpha activation in a Children’s Oncology Group randomized trial of interleukin-2 therapy for pediatric acute myeloid leukemia. Pediatr Blood Cancer. 2011;57:398–405.

    Article  PubMed  PubMed Central  Google Scholar 

  80. Roper M, Smith MA, Sondel PM, et al. A phase I study of interleukin-2 in children with cancer. Am J Pediatr Hematol Oncol. 1992;14:305–11.

    Article  CAS  PubMed  Google Scholar 

  81. Ladenstein R, Potschger U, Siabalis D, et al. Dose finding study for the use of subcutaneous recombinant interleukin-2 to augment natural killer cell numbers in an outpatient setting for stage 4 neuroblastoma after megatherapy and autologous stem-cell reinfusion. J Clin Oncol. 2011;29:441–8.

    Article  CAS  PubMed  Google Scholar 

  82. Fujii S, Shimizu K, Kronenberg M, Steinman RM. Prolonged IFN-gamma-producing NKT response induced with alpha-galactosylceramide-loaded DCs. Nat Immunol. 2002;3:867–74.

    Article  CAS  PubMed  Google Scholar 

  83. Wang J, Sun ZM, Cao LL, Li Q. Biological characteristics of cord blood natural killer cells induced and amplified with IL-2 and IL-15. Zhongguo Shi Yan Xue Ye Xue Za Zhi. 2012;20:731–5.

    PubMed  Google Scholar 

  84. Zamai L, Del Zotto G, Buccella F, et al. Cytotoxic functions and susceptibility to apoptosis of human CD56(bright) NK cells differentiated in vitro from CD34(+) hematopoietic progenitors. Cytometry A. 2012;81:294–302.

    Article  PubMed  CAS  Google Scholar 

  85. Rubnitz JE, Inaba H, Ribeiro RC, et al. NKAML: a pilot study to determine the safety and feasibility of haploidentical natural killer cell transplantation in childhood acute myeloid leukemia. J Clin Oncol. 2010;28:955–9.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  86. Gamero AM, Ussery D, Reintgen DS, Puleo CA, Djeu JY. Interleukin 15 induction of lymphokine-activated killer cell function against autologous tumor cells in melanoma patient lymphocytes by a CD18-dependent, perforin-related mechanism. Cancer Res. 1995;55:4988–94.

    CAS  PubMed  Google Scholar 

  87. Wren L, Parsons MS, Isitman G, et al. Influence of cytokines on HIV-specific antibody-dependent cellular cytotoxicity activation profile of natural killer cells. PLoS One. 2012;7:e38580.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  88. Carson WE, Giri JG, Lindemann MJ, et al. Interleukin (IL) 15 is a novel cytokine that activates human natural killer cells via components of the IL-2 receptor. J Exp Med. 1994;180:1395–403.

    Article  CAS  PubMed  Google Scholar 

  89. Choi SS, Chhabra VS, Nguyen QH, Ank BJ, Stiehm ER, Roberts RL. Interleukin-15 enhances cytotoxicity, receptor expression, and expansion of neonatal natural killer cells in long-term culture. Clin Diagn Lab Immunol. 2004;11:879–88.

    CAS  PubMed  PubMed Central  Google Scholar 

  90. Miller JS, Soignier Y, Panoskaltsis-Mortari A, et al. Successful adoptive transfer and in vivo expansion of human haploidentical NK cells in patients with cancer. Blood. 2005;105:3051–7.

    Article  CAS  PubMed  Google Scholar 

  91. Moga E, Alvarez E, Canto E, et al. NK cells stimulated with IL-15 or CpG ODN enhance rituximab-dependent cellular cytotoxicity against B-cell lymphoma. Exp Hematol. 2008;36:69–77.

    Article  CAS  PubMed  Google Scholar 

  92. Moga E, Canto E, Vidal S, Juarez C, Sierra J, Briones J. Interleukin-15 enhances rituximab-dependent cytotoxicity against chronic lymphocytic leukemia cells and overcomes transforming growth factor beta-mediated immunosuppression. Exp Hematol. 2011;39:1064–71.

    Article  CAS  PubMed  Google Scholar 

  93. Roberti MP, Barrio MM, Bravo AI, et al. IL-15 and IL-2 increase Cetuximab-mediated cellular cytotoxicity against triple negative breast cancer cell lines expressing EGFR. Breast Cancer Res Treat. 2011;130:465–75.

    Article  CAS  PubMed  Google Scholar 

  94. Bachanova V, Cooley S, Defor TE, et al. Clearance of acute myeloid leukemia by haploidentical natural killer cells is improved using IL-2 diphtheria toxin fusion protein. Blood. 2014;123:3855–63.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  95. Conlon KC, Lugli E, Welles HC, et al. Redistribution, hyperproliferation, activation of natural killer cells and CD8 T cells, and cytokine production during first-in-human clinical trial of recombinant human interleukin-15 in patients with cancer. J Clin Oncol. 2015;33:74–82.

    Article  CAS  PubMed  Google Scholar 

  96. Schmidt H, Brown J, Mouritzen U, et al. Safety and clinical effect of subcutaneous human interleukin-21 in patients with metastatic melanoma or renal cell carcinoma: a phase I trial. Clin Cancer Res. 2010;16:5312–9.

    Article  CAS  PubMed  Google Scholar 

  97. Reddy N, Hernandez-Ilizaliturri FJ, Deeb G, et al. Immunomodulatory drugs stimulate natural killer-cell function, alter cytokine production by dendritic cells, and inhibit angiogenesis enhancing the anti-tumour activity of rituximab in vivo. Br J Haematol. 2008;140:36–45.

    CAS  PubMed  Google Scholar 

  98. Wu L, Adams M, Carter T, et al. lenalidomide enhances natural killer cell and monocyte-mediated antibody-dependent cellular cytotoxicity of rituximab-treated CD20+ tumor cells. Clin Cancer Res. 2008;14:4650–7.

    Article  CAS  PubMed  Google Scholar 

  99. Berg SL, Cairo MS, Russell H, et al. Safety, pharmacokinetics, and immunomodulatory effects of lenalidomide in children and adolescents with relapsed/refractory solid tumors or myelodysplastic syndrome: a Children’s Oncology Group Phase I Consortium report. J Clin Oncol. 2011;29:316–23.

    Article  CAS  PubMed  Google Scholar 

  100. Lundqvist A, Abrams SI, Schrump DS, et al. Bortezomib and depsipeptide sensitize tumors to tumor necrosis factor-related apoptosis-inducing ligand: a novel method to potentiate natural killer cell tumor cytotoxicity. Cancer Res. 2006;66:7317–25.

    Article  CAS  PubMed  Google Scholar 

  101. Lundqvist A, Berg M, Smith A, Childs RW. Bortezomib treatment to potentiate the anti-tumor immunity of ex-vivo expanded adoptively infused autologous natural killer cells. J Cancer. 2011;2:383–5.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  102. Piperdi B, Ling YH, Liebes L, Muggia F, Perez-Soler R. Bortezomib: understanding the mechanism of action. Mol Cancer Ther. 2011;10:2029–30.

    Article  CAS  PubMed  Google Scholar 

  103. Blaney SM, Bernstein M, Neville K, et al. Phase I study of the proteasome inhibitor bortezomib in pediatric patients with refractory solid tumors: a Children’s Oncology Group study (ADVL0015). J Clin Oncol. 2004;22:4804–9.

    Article  CAS  PubMed  Google Scholar 

  104. Horton TM, Pati D, Plon SE, et al. A phase 1 study of the proteasome inhibitor bortezomib in pediatric patients with refractory leukemia: a Children's Oncology Group study. Clin Cancer Res. 2007;13:1516–22.

    Article  CAS  PubMed  Google Scholar 

  105. Messinger Y, Gaynon P, Raetz E, et al. Phase I study of bortezomib combined with chemotherapy in children with relapsed childhood acute lymphoblastic leukemia (ALL): a report from the therapeutic advances in childhood leukemia (TACL) consortium. Pediatr Blood Cancer. 2010;55:254–9.

    Article  PubMed  Google Scholar 

  106. Muscal JA, Thompson PA, Horton TM, et al. A phase I trial of vorinostat and bortezomib in children with refractory or recurrent solid tumors: a Children’s Oncology Group phase I consortium study (ADVL0916). Pediatr Blood Cancer. 2013;60:390–5.

    Article  CAS  PubMed  Google Scholar 

  107. Horton TM, Drachtman RA, Chen L, et al. A phase 2 study of bortezomib in combination with ifosfamide/vinorelbine in paediatric patients and young adults with refractory/recurrent Hodgkin lymphoma: a Children’s Oncology Group study. Br J Haematol. 2015;170:118–22.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  108. Armeanu S, Bitzer M, Lauer UM, et al. Natural killer cell-mediated lysis of hepatoma cells via specific induction of NKG2D ligands by the histone deacetylase inhibitor sodium valproate. Cancer Res. 2005;65:6321–9.

    Article  CAS  PubMed  Google Scholar 

  109. Skov S, Pedersen MT, Andresen L, Straten PT, Woetmann A, Odum N. Cancer cells become susceptible to natural killer cell killing after exposure to histone deacetylase inhibitors due to glycogen synthase kinase-3-dependent expression of MHC class I-related chain A and B. Cancer Res. 2005;65:11136–45.

    Article  CAS  PubMed  Google Scholar 

  110. Son CH, Keum JH, Yang K, et al. Synergistic enhancement of NK cell-mediated cytotoxicity by combination of histone deacetylase inhibitor and ionizing radiation. Radiat Oncol. 2014;9:49.

    Article  PubMed  PubMed Central  CAS  Google Scholar 

  111. Su JM, Li XN, Thompson P, et al. Phase 1 study of valproic acid in pediatric patients with refractory solid or CNS tumors: a children’s oncology group report. Clin Cancer Res. 2011;17:589–97.

    Article  CAS  PubMed  Google Scholar 

  112. Fouladi M, Furman WL, et al. Phase I study of depsipeptide in pediatric patients with refractory solid tumors: a Children’s Oncology Group report. J Clin Oncol. 2006;24:3678–85.

    Article  CAS  PubMed  Google Scholar 

  113. Gupta P, Han SY, Holgado-Madruga M, et al. Development of an EGFRvIII specific recombinant antibody. BMC Biotechnol. 2010;10:72.

    Article  PubMed  PubMed Central  CAS  Google Scholar 

  114. Baragano Raneros A, Martin-Palanco V, Fernandez AF, et al. Methylation of NKG2D ligands contributes to immune system evasion in acute myeloid leukemia. Genes Immun. 2015;16:71–82.

    Article  CAS  PubMed  Google Scholar 

  115. Pfeiffer MM, Burow H, Schleicher S, Handgretinger R, Lang P. Influence of histone deacetylase inhibitors and DNA-methyltransferase inhibitors on the NK cell-mediated lysis of pediatric B-lineage leukemia. Front Oncol. 2013;3:99.

    Article  PubMed  PubMed Central  Google Scholar 

  116. Phillips CL, Davies SM, McMasters R, et al. Low dose decitabine in very high risk relapsed or refractory acute myeloid leukaemia in children and young adults. Br J Haematol. 2013;161:406–10.

    Article  CAS  PubMed  Google Scholar 

  117. Weng WK, Levy R. Two immunoglobulin G fragment C receptor polymorphisms independently predict response to rituximab in patients with follicular lymphoma. J Clin Oncol. 2003;21:3940–7.

    Article  CAS  PubMed  Google Scholar 

  118. Goldman S, Smith L, Galardy P, et al. Rituximab with chemotherapy in children and adolescents with central nervous system and/or bone marrow-positive Burkitt lymphoma/leukaemia: a Children’s Oncology Group Report. Br J Haematol. 2014;167:394–401.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  119. Yu AL, Gilman AL, Ozkaynak MF, et al. Anti-GD2 antibody with GM-CSF, interleukin-2, and isotretinoin for neuroblastoma. N Engl J Med. 2010;363:1324–34.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  120. Cheung NK, Cheung IY, Kushner BH, et al. Murine anti-GD2 monoclonal antibody 3F8 combined with granulocyte-macrophage colony-stimulating factor and 13-cis-retinoic acid in high-risk patients with stage 4 neuroblastoma in first remission. J Clin Oncol. 2012;30:3264–70.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  121. Benson DM Jr, Bakan CE, Mishra A, et al. The PD-1/PD-L1 axis modulates the natural killer cell versus multiple myeloma effect: a therapeutic target for CT-011, a novel monoclonal anti-PD-1 antibody. Blood. 2010;116:2286–94.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  122. Contardi E, Palmisano GL, Tazzari PL, et al. CTLA-4 is constitutively expressed on tumor cells and can trigger apoptosis upon ligand interaction. Int J Cancer. 2005;117:538–50.

    Article  CAS  PubMed  Google Scholar 

  123. Pistillo MP, Tazzari PL, Palmisano GL, et al. CTLA-4 is not restricted to the lymphoid cell lineage and can function as a target molecule for apoptosis induction of leukemic cells. Blood. 2003;101:202–9.

    Article  CAS  PubMed  Google Scholar 

  124. Jie HB, Schuler PJ, Lee SC, et al. CTLA-4(+) regulatory T cells increased in cetuximab-treated head and neck cancer patients suppress NK cell cytotoxicity and correlate with poor prognosis. Cancer Res. 2015;75:2200–10.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  125. Romano E, Kusio-Kobialka M, Foukas PG, et al. Ipilimumab-dependent cell-mediated cytotoxicity of regulatory T cells ex vivo by nonclassical monocytes in melanoma patients. Proc Natl Acad Sci U S A. 2015;112:6140–5.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  126. Simpson TR, Li F, Montalvo-Ortiz W, et al. Fc-dependent depletion of tumor-infiltrating regulatory T cells co-defines the efficacy of anti-CTLA-4 therapy against melanoma. J Exp Med. 2013;210:1695–710.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  127. Laurent S, Queirolo P, Boero S, et al. The engagement of CTLA-4 on primary melanoma cell lines induces antibody-dependent cellular cytotoxicity and TNF-alpha production. J Transl Med. 2013;11:108.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  128. Merchant MS, Wright M, Baird K, et al. Phase I clinical trial of ipilimumab in pediatric patients with advanced solid tumors. Clin Cancer Res. 2016;22:1364–70.

    Article  CAS  PubMed  Google Scholar 

  129. Ferrara C, Grau S, Jager C, et al. Unique carbohydrate-carbohydrate interactions are required for high affinity binding between FcgammaRIII and antibodies lacking core fucose. Proc Natl Acad Sci U S A. 2011;108:12669–74.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  130. Forthal DN, Gach JS, Landucci G, et al. Fc-glycosylation influences Fcgamma receptor binding and cell-mediated anti-HIV activity of monoclonal antibody 2G12. J Immunol. 2010;185:6876–82.

    Article  CAS  PubMed  Google Scholar 

  131. Ayello J, Berg S, Krailo M, van de Ven C, Ingle A, Lewis D, Harrison L, Blaney S, Adamson P, Cairo M. Lenalidomide significantly enhances circulating serum levels of IL-2 and IL-15 levels, NK expansion and activation and NK and LAK cytotoxicity in children with refractory/recurrent solid tumors: a Children’s Oncology Group phase I consoritium report. Blood. 2008;122:3068.

    Google Scholar 

  132. Lazar GA, Dang W, Karki S, et al. Engineered antibody Fc variants with enhanced effector function. Proc Natl Acad Sci U S A. 2006;103:4005–10.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  133. Loo D, Alderson RF, Chen FZ, et al. Development of an Fc-enhanced anti-B7-H3 monoclonal antibody with potent antitumor activity. Clin Cancer Res. 2012;18:3834–45.

    Article  CAS  PubMed  Google Scholar 

  134. Casorati G, de Lalla C, Dellabona P. Invariant natural killer T cells reconstitution and the control of leukemia relapse in pediatric haploidentical hematopoietic stem cell transplantation. Oncoimmunology. 2012;1:355–7.

    Article  PubMed  PubMed Central  Google Scholar 

  135. Gumperz JE, Miyake S, Yamamura T, Brenner MB. Functionally distinct subsets of CD1d-restricted natural killer T cells revealed by CD1d tetramer staining. J Exp Med. 2002;195:625–36.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  136. Wilcox RA, Tamada K, Strome SE, Chen L. Signaling through NK cell-associated CD137 promotes both helper function for CD8+ cytolytic T cells and responsiveness to IL-2 but not cytolytic activity. J Immunol. 2002;169:4230–6.

    Article  CAS  PubMed  Google Scholar 

  137. Melero I, Shuford WW, Newby SA, et al. Monoclonal antibodies against the 4-1BB T-cell activation molecule eradicate established tumors. Nat Med. 1997;3:682–5.

    Article  CAS  PubMed  Google Scholar 

  138. Melero I, Johnston JV, Shufford WW, Mittler RS, Chen L. NK1.1 cells express 4-1BB (CDw137) costimulatory molecule and are required for tumor immunity elicited by anti-4-1BB monoclonal antibodies. Cell Immunol. 1998;190:167–72.

    Article  CAS  PubMed  Google Scholar 

  139. Kohrt HE, Houot R, Goldstein MJ, et al. CD137 stimulation enhances the antilymphoma activity of anti-CD20 antibodies. Blood. 2011;117:2423–32.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  140. Kohrt HE, Houot R, Weiskopf K, et al. Stimulation of natural killer cells with a CD137-specific antibody enhances trastuzumab efficacy in xenotransplant models of breast cancer. J Clin Invest. 2012;122:1066–75.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  141. Kohrt HE, Colevas AD, Houot R, et al. Targeting CD137 enhances the efficacy of cetuximab. J Clin Invest. 2014;124:2668–82.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  142. Benson DM Jr, Bakan CE, Zhang S, et al. IPH2101, a novel anti-inhibitory KIR antibody, and lenalidomide combine to enhance the natural killer cell versus multiple myeloma effect. Blood. 2011;118:6387–91.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  143. Romagne F, Andre P, Spee P, et al. Preclinical characterization of 1-7F9, a novel human anti-KIR receptor therapeutic antibody that augments natural killer-mediated killing of tumor cells. Blood. 2009;114:2667–77.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  144. Sola C, Andre P, Lemmers C, et al. Genetic and antibody-mediated reprogramming of natural killer cell missing-self recognition in vivo. Proc Natl Acad Sci U S A. 2009;106:12879–84.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  145. Binyamin L, Alpaugh RK, Hughes TL, Lutz CT, Campbell KS, Weiner LM. Blocking NK cell inhibitory self-recognition promotes antibody-dependent cellular cytotoxicity in a model of anti-lymphoma therapy. J Immunol. 2008;180:6392–401.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  146. Sola C, Chanuc F, Thielens A, Fuseri N, Morel Y, Blery M, Andre P, Vivier E, Graziano R, Romagne F, Bonnafous C. Anti-tumoral efficacy of therapeutic human anti-KIR antibody (Lirilumab/BMS-986015/IPH2102) in a preclinical xenograft tumor model. J Immunother. Cancer. 2013;1(Suppl 1):P40.

    Article  PubMed Central  Google Scholar 

  147. Vey N, Bourhis JH, Boissel N, et al. A phase 1 trial of the anti-inhibitory KIR mAb IPH2101 for AML in complete remission. Blood. 2012;120:4317–23.

    Article  CAS  PubMed  Google Scholar 

  148. Germain C, Larbouret C, Cesson V, et al. MHC class I-related chain A conjugated to antitumor antibodies can sensitize tumor cells to specific lysis by natural killer cells. Clin Cancer Res. 2005;11:7516–22.

    Article  CAS  PubMed  Google Scholar 

  149. von Strandmann EP, Hansen HP, Reiners KS, et al. A novel bispecific protein (ULBP2-BB4) targeting the NKG2D receptor on natural killer (NK) cells and CD138 activates NK cells and has potent antitumor activity against human multiple myeloma in vitro and in vivo. Blood. 2006;107:1955–62.

    Article  CAS  Google Scholar 

  150. Buhtoiarov IN, Neal ZC, Gan J, et al. Differential internalization of hu14.18-IL2 immunocytokine by NK and tumor cell: impact on conjugation, cytotoxicity, and targeting. J Leukoc Biol. 2011;89:625–38.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  151. Lode HN, Xiang R, Dreier T, Varki NM, Gillies SD, Reisfeld RA. Natural killer cell-mediated eradication of neuroblastoma metastases to bone marrow by targeted interleukin-2 therapy. Blood. 1998;91:1706–15.

    CAS  PubMed  Google Scholar 

  152. Osenga KL, Hank JA, Albertini MR, et al. A phase I clinical trial of the hu14.18-IL2 (EMD 273063) as a treatment for children with refractory or recurrent neuroblastoma and melanoma: a study of the Children’s Oncology Group. Clin Cancer Res. 2006;12:1750–9.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  153. Shusterman S, London WB, Gillies SD, et al. Antitumor activity of hu14.18-IL2 in patients with relapsed/refractory neuroblastoma: a Children’s Oncology Group (COG) phase II study. J Clin Oncol. 2010;28:4969–75.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  154. Shusterman S, London WB, Hank JA, Parisi MT, Shulkin BL, Servases S, Naranjo A, Shimada H, Gan J, Gillies SD, Maris JM, Park JR, Sondel PM. A feasibility and phase II study of the hu14.18-IL2 immunocytokine in combination with GM-CSF and isotretinoin in patients with recurrent or refractory neuroblastoma: a Children’s Oncology Group Study. Pediatric Oncol. 2015;33(15):10017.

    Google Scholar 

  155. Gleason MK, Verneris MR, Todhunter DA, et al. Bispecific and trispecific killer cell engagers directly activate human NK cells through CD16 signaling and induce cytotoxicity and cytokine production. Mol Cancer Ther. 2012;11:2674–84.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  156. Miller JS, Felice M, McElmurry R, McCullar V, Zhou X, Tolar J, Schmohl J, Panoskaltsis-Mortari A, Zhang B, Taras E, Verneris M, Cooley S, Weisdorf D, Blazar B, Vallera D. Trispecific Killer Engagers (TriKEs) that contain IL-15 to make NK cells antigen specific and to sustain their persistence and expansion. Blood. 2015;22:83158.

    Google Scholar 

  157. Curti A, Ruggeri L, D'Addio A, et al. Successful transfer of alloreactive haploidentical KIR ligand-mismatched natural killer cells after infusion in elderly high risk acute myeloid leukemia patients. Blood. 2011;118:3273–9.

    Article  CAS  PubMed  Google Scholar 

  158. Geller MA, Cooley S, Judson PL, et al. A phase II study of allogeneic natural killer cell therapy to treat patients with recurrent ovarian and breast cancer. Cytotherapy. 2011;13:98–107.

    Article  CAS  PubMed  Google Scholar 

  159. Brehm C, Huenecke S, Quaiser A, et al. IL-2 stimulated but not unstimulated NK cells induce selective disappearance of peripheral blood cells: concomitant results to a phase I/II study. PLoS One. 2011;6:e27351.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  160. Passweg JR, Tichelli A, Meyer-Monard S, et al. Purified donor NK-lymphocyte infusion to consolidate engraftment after haploidentical stem cell transplantation. Leukemia. 2004;18:1835–8.

    Article  CAS  PubMed  Google Scholar 

  161. Rizzieri DA, Dev P, Long GD, et al. Response and toxicity of donor lymphocyte infusions following T-cell depleted non-myeloablative allogeneic hematopoietic SCT from 3-6/6 HLA matched donors. Bone Marrow Transplant. 2009;43:327–33.

    Article  CAS  PubMed  Google Scholar 

  162. Shaffer BC, Le Luduec JB, Forlenza C, et al. Phase II study of haploidentical natural killer cell infusion for treatment of relapsed or persistent myeloid malignancies following allogeneic hematopoietic cell transplantation. Biol Blood Marrow Transplant. 2016;22:705–9.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  163. Stern M, Passweg JR, Meyer-Monard S, et al. Pre-emptive immunotherapy with purified natural killer cells after haploidentical SCT: a prospective phase II study in two centers. Bone Marrow Transplant. 2013;48:433–8.

    Article  CAS  PubMed  Google Scholar 

  164. Yoon SR, Lee YS, Yang SH, et al. Generation of donor natural killer cells from CD34(+) progenitor cells and subsequent infusion after HLA-mismatched allogeneic hematopoietic cell transplantation: a feasibility study. Bone Marrow Transplant. 2010;45:1038–46.

    Article  CAS  PubMed  Google Scholar 

  165. Choi I, Yoon SR, Park SY, et al. Donor-derived natural killer cells infused after human leukocyte antigen-haploidentical hematopoietic cell transplantation: a dose-escalation study. Biol Blood Marrow Transplant. 2014;20:696–704.

    Article  CAS  PubMed  Google Scholar 

  166. Shah NN, Baird K, Delbrook CP, et al. Acute GVHD in patients receiving IL-15/4-1BBL activated NK cells following T-cell-depleted stem cell transplantation. Blood. 2015;125:784–92.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  167. Arai S, Meagher R, Swearingen M, et al. Infusion of the allogeneic cell line NK-92 in patients with advanced renal cell cancer or melanoma: a phase I trial. Cytotherapy. 2008;10:625–32.

    Article  CAS  PubMed  Google Scholar 

  168. Altvater B, Landmeier S, Pscherer S, et al. 2B4 (CD244) signaling by recombinant antigen-specific chimeric receptors costimulates natural killer cell activation to leukemia and neuroblastoma cells. Clin Cancer Res. 2009;15:4857–66.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  169. Tonn T, Schwabe D, Klingemann HG, et al. Treatment of patients with advanced cancer with the natural killer cell line NK-92. Cytotherapy. 2013;15:1563–158.

    Article  CAS  PubMed  Google Scholar 

  170. Alsamah W, Romia Y. Modification of natural killer cells to target tumors. Int J Pharm Clin Res. 2014;6:97–100.

    Google Scholar 

  171. Chang YH, Connolly J, Shimasaki N, Mimura K, Kono K, Campana D. A chimeric receptor with NKG2D specificity enhances natural killer cell activation and killing of tumor cells. Cancer Res. 2013;73:1777–86.

    Article  CAS  PubMed  Google Scholar 

  172. Chu Y, Ayello J, Lo L, Katz J, Yahr A, et al Expanded natural killer (NK) cells transfected with anti-CD20 chimeric antigen receptor (CAR) mRNA have significant cytotoxicity against poor risk B-Cell (CD20+) leukemia/lymphoma (B-L/L). Blood. 2012;120:abstr. 3007.

    Google Scholar 

  173. Imai C, Iwamoto S, Campana D. Genetic modification of primary natural killer cells overcomes inhibitory signals and induces specific killing of leukemic cells. Blood. 2005;106:376–83.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  174. Kruschinski A, Moosmann A, Poschke I, et al. Engineering antigen-specific primary human NK cells against HER-2 positive carcinomas. Proc Natl Acad Sci U S A. 2008;105:17481–6.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  175. Li L, Liu LN, Feller S, et al. Expression of chimeric antigen receptors in natural killer cells with a regulatory-compliant non-viral method. Cancer Gene Ther. 2010;17:147–54.

    Article  CAS  PubMed  Google Scholar 

  176. Ni Z, Knorr DA, Bendzick L, Allred J, Kaufman DS. Expression of chimeric receptor CD4zeta by natural killer cells derived from human pluripotent stem cells improves in vitro activity but does not enhance suppression of HIV infection in vivo. Stem Cells. 2014;32:1021–31.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  177. Boissel L, Betancur M, Lu W, et al. Comparison of mRNA and lentiviral based transfection of natural killer cells with chimeric antigen receptors recognizing lymphoid antigens. Leuk Lymphoma. 2012;53:958–65.

    Article  CAS  PubMed  Google Scholar 

  178. Boissel L, Betancur M, Wels WS, Tuncer H, Klingemann H. Transfection with mRNA for CD19 specific chimeric antigen receptor restores NK cell mediated killing of CLL cells. Leuk Res. 2009;33:1255–9.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  179. Boissel L, Betancur-Boissel M, Lu W, et al. Retargeting NK-92 cells by means of CD19- and CD20-specific chimeric antigen receptors compares favorably with antibody-dependent cellular cytotoxicity. Oncoimmunology. 2013;2:e26527.

    Article  PubMed  PubMed Central  Google Scholar 

  180. Chu J, Deng Y, Benson DM, et al. CS1-specific chimeric antigen receptor (CAR)-engineered natural killer cells enhance in vitro and in vivo antitumor activity against human multiple myeloma. Leukemia. 2014;28:917–27.

    Article  CAS  PubMed  Google Scholar 

  181. Esser R, Muller T, Stefes D, et al. NK cells engineered to express a GD2 -specific antigen receptor display built-in ADCC-like activity against tumour cells of neuroectodermal origin. J Cell Mol Med. 2012;16:569–81.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  182. Jiang H, Zhang W, Shang P, et al. Transfection of chimeric anti-CD138 gene enhances natural killer cell activation and killing of multiple myeloma cells. Mol Oncol. 2014;8:297–310.

    Article  CAS  PubMed  Google Scholar 

  183. Liu H, Yang B, Sun T, et al. Specific growth inhibition of ErbB2expressing human breast cancer cells by genetically modified NK92 cells. Oncol Rep. 2015;33:95–102.

    CAS  PubMed  Google Scholar 

  184. Muller T, Uherek C, Maki G, et al. Expression of a CD20-specific chimeric antigen receptor enhances cytotoxic activity of NK cells and overcomes NK-resistance of lymphoma and leukemia cells. Cancer Immunol Immunother. 2008;57:411–23.

    Article  PubMed  CAS  Google Scholar 

  185. Sahm C, Schonfeld K, Wels WS. Expression of IL-15 in NK cells results in rapid enrichment and selective cytotoxicity of gene-modified effectors that carry a tumor-specific antigen receptor. Cancer Immunol Immunother. 2012;61:1451–61.

    Article  CAS  PubMed  Google Scholar 

  186. Schonfeld K, Sahm C, Zhang C, et al. Selective inhibition of tumor growth by clonal NK cells expressing an ErbB2/HER2-specific chimeric antigen receptor. Mol Ther. 2015;23:330–8.

    Article  PubMed  CAS  Google Scholar 

  187. Tassev DV, Cheng M, Cheung NK. Retargeting NK92 cells using an HLA-A2-restricted, EBNA3C-specific chimeric antigen receptor. Cancer Gene Ther. 2012;19:84–100.

    Article  CAS  PubMed  Google Scholar 

  188. Topfer K, Cartellieri M, Michen S, et al. DAP12-based activating chimeric antigen receptor for NK cell tumor immunotherapy. J Immunol. 2015;194:3201–12.

    Article  PubMed  CAS  Google Scholar 

  189. Uherek C, Tonn T, Uherek B, et al. Retargeting of natural killer-cell cytolytic activity to ErbB2-expressing cancer cells results in efficient and selective tumor cell destruction. Blood. 2002;100:1265–73.

    CAS  PubMed  Google Scholar 

  190. Zhang G, Liu R, Zhu X, et al. Retargeting NK-92 for anti-melanoma activity by a TCR-like single-domain antibody. Immunol Cell Biol. 2013;91:615–24.

    Article  CAS  PubMed  Google Scholar 

  191. Konstantinidis KV, Alici E, Aints A, Christensson B, Ljunggren HG, Dilber MS. Targeting IL-2 to the endoplasmic reticulum confines autocrine growth stimulation to NK-92 cells. Exp Hematol. 2005;33:159–64.

    Article  CAS  PubMed  Google Scholar 

  192. Nagashima S, Mailliard R, Kashii Y, et al. Stable transduction of the interleukin-2 gene into human natural killer cell lines and their phenotypic and functional characterization in vitro and in vivo. Blood. 1998;91:3850–61.

    CAS  PubMed  Google Scholar 

  193. Imamura M, Shook D, Kamiya T, et al. Autonomous growth and increased cytotoxicity of natural killer cells expressing membrane-bound interleukin-15. Blood. 2014;124:1081–8.

    Article  CAS  PubMed  Google Scholar 

  194. Carlsten M, Li L, Su S, Berg M, Reger R, Peshwa M, Childs R. Clinical-grade mRNA electroporation of NK cells: a novel and highly efficient method to genetically reprogram human NK cells for cancer immunotherapy. Blood. 2014;124:2153.

    Google Scholar 

  195. Furutani E, Su S, Smith A, Berg M, Childs R (2010). siRNA inactivation of the inhibitory receptor NKG2Azz augments the anti-tumor effects of adoptively transferred NK cells in tumor-bearing hosts. ASH Annual Meeting Abstracts: Orlando.

    Google Scholar 

  196. Figueiredo C, Seltsam A, Blasczyk R. Permanent silencing of NKG2A expression for cell-based therapeutics. J Mol Med (Berl). 2009;87:199–210.

    Article  CAS  Google Scholar 

  197. Kawano T, Nakayama T, Kamada N, et al. Antitumor cytotoxicity mediated by ligand-activated human V alpha24 NKT cells. Cancer Res. 1999;59:5102–5.

    CAS  PubMed  Google Scholar 

  198. Nieda M, Nicol A, Koezuka Y, et al. TRAIL expression by activated human CD4(+)V alpha 24NKT cells induces in vitro and in vivo apoptosis of human acute myeloid leukemia cells. Blood. 2001;97:2067–74.

    Article  CAS  PubMed  Google Scholar 

  199. Lee YJ, Holzapfel KL, Zhu J, Jameson SC, Hogquist KA. Steady-state production of IL-4 modulates immunity in mouse strains and is determined by lineage diversity of iNKT cells. Nat Immunol. 2013;14:1146–54.

    Article  CAS  PubMed  Google Scholar 

  200. Moreira-Teixeira L, Resende M, Devergne O, et al. Rapamycin combined with TGF-beta converts human invariant NKT cells into suppressive Foxp3+ regulatory cells. J Immunol. 2012;188:624–31.

    Article  CAS  PubMed  Google Scholar 

  201. Dhodapkar MV, Geller MD, Chang DH, et al. A reversible defect in natural killer T cell function characterizes the progression of premalignant to malignant multiple myeloma. J Exp Med. 2003;197:1667–76.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  202. Fais F, Morabito F, Stelitano C, et al. CD1d is expressed on B-chronic lymphocytic leukemia cells and mediates alpha-galactosylceramide presentation to natural killer T lymphocytes. Int J Cancer. 2004;109:402–11.

    Article  CAS  PubMed  Google Scholar 

  203. Fais F, Tenca C, Cimino G, et al. CD1d expression on B-precursor acute lymphoblastic leukemia subsets with poor prognosis. Leukemia. 2005;19:551–6.

    Article  CAS  PubMed  Google Scholar 

  204. Metelitsa LS, Weinberg KI, Emanuel PD, Seeger RC. Expression of CD1d by myelomonocytic leukemias provides a target for cytotoxic NKT cells. Leukemia. 2003;17:1068–77.

    Article  CAS  PubMed  Google Scholar 

  205. Renukaradhya GJ, Khan MA, Vieira M, Du W, Gervay-Hague J, Brutkiewicz RR. Type I NKT cells protect (and type II NKT cells suppress) the host’s innate antitumor immune response to a B-cell lymphoma. Blood. 2008;111:5637–45.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  206. Xu C, de Vries R, Visser L, et al. Expression of CD1d and presence of invariant NKT cells in classical Hodgkin lymphoma. Am J Hematol. 2010;85:539–41.

    Article  PubMed  Google Scholar 

  207. Chong TW, Goh FY, Sim MY, et al. CD1d expression in renal cell carcinoma is associated with higher relapse rates, poorer cancer-specific and overall survival. J Clin Pathol. 2015;68:200–5.

    Article  PubMed  Google Scholar 

  208. Hix LM, Shi YH, Brutkiewicz RR, Stein PL, Wang CR, Zhang M. CD1d-expressing breast cancer cells modulate NKT cell-mediated antitumor immunity in a murine model of breast cancer metastasis. PLoS One. 2011;6:e20702.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  209. Nowak M, Arredouani MS, Tun-Kyi A, et al. Defective NKT cell activation by CD1d+ TRAMP prostate tumor cells is corrected by interleukin-12 with alpha-galactosylceramide. PLoS One. 2010;5:e11311.

    Article  PubMed  PubMed Central  CAS  Google Scholar 

  210. Tahir SM, Cheng O, Shaulov A, et al. Loss of IFN-gamma production by invariant NK T cells in advanced cancer. J Immunol. 2001;167:4046–50.

    Article  CAS  PubMed  Google Scholar 

  211. Fallarini S, Paoletti T, Orsi Battaglini N, Lombardi G. Invariant NKT cells increase drug-induced osteosarcoma cell death. Br J Pharmacol. 2012;167:1533–49.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  212. Metelitsa LS. Anti-tumor potential of type-I NKT cells against CD1d-positive and CD1d-negative tumors in humans. Clin Immunol. 2011;140:119–29.

    Article  CAS  PubMed  Google Scholar 

  213. Song L, Asgharzadeh S, Salo J, et al. Valpha24-invariant NKT cells mediate antitumor activity via killing of tumor-associated macrophages. J Clin Invest. 2009;119:1524–36.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  214. Chen YH, Chiu NM, Mandal M, Wang N, Wang CR. Impaired NK1+ T cell development and early IL-4 production in CD1-deficient mice. Immunity. 1997;6:459–67.

    Article  CAS  PubMed  Google Scholar 

  215. Giaccone G, Punt CJ, Ando Y, et al. A phase I study of the natural killer T-cell ligand alpha-galactosylceramide (KRN7000) in patients with solid tumors. Clin Cancer Res. 2002;8:3702–9.

    CAS  PubMed  Google Scholar 

  216. Molling JW, Kolgen W, van der Vliet HJ, et al. Peripheral blood IFN-gamma-secreting Valpha24+Vbeta11+ NKT cell numbers are decreased in cancer patients independent of tumor type or tumor load. Int J Cancer. 2005;116:87–93.

    Article  CAS  PubMed  Google Scholar 

  217. Molling JW, Langius JA, Langendijk JA, et al. Low levels of circulating invariant natural killer T cells predict poor clinical outcome in patients with head and neck squamous cell carcinoma. J Clin Oncol. 2007;25:862–8.

    Article  PubMed  Google Scholar 

  218. Najera Chuc AE, Cervantes LA, Retiguin FP, Ojeda JV, Maldonado ER. Low number of invariant NKT cells is associated with poor survival in acute myeloid leukemia. J Cancer Res Clin Oncol. 2012;138:1427–32.

    Article  CAS  PubMed  Google Scholar 

  219. Tachibana T, Onodera H, Tsuruyama T, et al. Increased intratumor Valpha24-positive natural killer T cells: a prognostic factor for primary colorectal carcinomas. Clin Cancer Res. 2005;11:7322–7.

    Article  CAS  PubMed  Google Scholar 

  220. de Lalla C, Rinaldi A, Montagna D, et al. Invariant NKT cell reconstitution in pediatric leukemia patients given HLA-haploidentical stem cell transplantation defines distinct CD4+ and CD4- subset dynamics and correlates with remission state. J Immunol. 2011;186:4490–9.

    Article  PubMed  CAS  Google Scholar 

  221. Lee PT, Benlagha K, Teyton L, Bendelac A. Distinct functional lineages of human V(alpha)24 natural killer T cells. J Exp Med. 2002;195:637–41.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  222. Montoya CJ, Pollard D, Martinson J, et al. Characterization of human invariant natural killer T subsets in health and disease using a novel invariant natural killer T cell-clonotypic monoclonal antibody, 6B11. Immunology. 2007;122:1–14.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  223. Swann JB, Uldrich AP, van Dommelen S, et al. Type I natural killer T cells suppress tumors caused by p53 loss in mice. Blood. 2009;113:6382–5.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  224. Crowe NY, Smyth MJ, Godfrey DI. A critical role for natural killer T cells in immunosurveillance of methylcholanthrene-induced sarcomas. J Exp Med. 2002;196:119–27.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  225. Ambrosino E, Terabe M, Halder RC, et al. Cross-regulation between type I and type II NKT cells in regulating tumor immunity: a new immunoregulatory axis. J Immunol. 2007;179:5126–36.

    Article  CAS  PubMed  Google Scholar 

  226. Hayakawa Y, Rovero S, Forni G, Smyth MJ. Alpha-galactosylceramide (KRN7000) suppression of chemical- and oncogene-dependent carcinogenesis. Proc Natl Acad Sci U S A. 2003;100:9464–9.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  227. Kawano T, Cui J, Koezuka Y, et al. Natural killer-like nonspecific tumor cell lysis mediated by specific ligand-activated Valpha14 NKT cells. Proc Natl Acad Sci U S A. 1998;95:5690–3.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  228. Kobayashi E, Motoki K, Uchida T, Fukushima H, Koezuka Y. KRN7000, a novel immunomodulator, and its antitumor activities. Oncol Res. 1995;7:529–34.

    CAS  PubMed  Google Scholar 

  229. Morita M, Motoki K, Akimoto K, et al. Structure-activity relationship of alpha-galactosylceramides against B16-bearing mice. J Med Chem. 1995;38:2176–87.

    Article  CAS  PubMed  Google Scholar 

  230. Parekh VV, Wilson MT, Olivares-Villagomez D, et al. Glycolipid antigen induces long-term natural killer T cell anergy in mice. J Clin Invest. 2005;115:2572–83.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  231. Swann JB, Coquet JM, Smyth MJ, Godfrey DI. CD1-restricted T cells and tumor immunity. Curr Top Microbiol Immunol. 2007;314:293–323.

    CAS  PubMed  Google Scholar 

  232. Hayakawa Y, Takeda K, Yagita H, et al. Critical contribution of IFN-gamma and NK cells, but not perforin-mediated cytotoxicity, to anti-metastatic effect of alpha-galactosylceramide. Eur J Immunol. 2001;31:1720–7.

    Article  CAS  PubMed  Google Scholar 

  233. Nakagawa R, Nagafune I, Tazunoki Y, et al. Mechanisms of the antimetastatic effect in the liver and of the hepatocyte injury induced by alpha-galactosylceramide in mice. J Immunol. 2001;166:6578–84.

    Article  CAS  PubMed  Google Scholar 

  234. Smyth MJ, Crowe NY, Pellicci DG, et al. Sequential production of interferon-gamma by NK1.1(+) T cells and natural killer cells is essential for the antimetastatic effect of alpha-galactosylceramide. Blood. 2002;99:1259–66.

    Article  CAS  PubMed  Google Scholar 

  235. Shimizu K, Goto A, Fukui M, Taniguchi M, Fujii S. Tumor cells loaded with alpha-galactosylceramide induce innate NKT and NK cell-dependent resistance to tumor implantation in mice. J Immunol. 2007;178:2853–61.

    Article  CAS  PubMed  Google Scholar 

  236. Chang YJ, Huang JR, Tsai YC, et al. Potent immune-modulating and anticancer effects of NKT cell stimulatory glycolipids. Proc Natl Acad Sci U S A. 2007;104:10299–304.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  237. Huang JR, Tsai YC, Chang YJ, et al. alpha-Galactosylceramide but not phenyl-glycolipids induced NKT cell anergy and IL-33-mediated myeloid-derived suppressor cell accumulation via upregulation of egr2/3. J Immunol. 2014;192:1972–81.

    Article  CAS  PubMed  Google Scholar 

  238. O'Konek JJ, Illarionov P, Khursigara DS, et al. Mouse and human iNKT cell agonist beta-mannosylceramide reveals a distinct mechanism of tumor immunity. J Clin Invest. 2011;121:683–94.

    Article  PubMed  PubMed Central  CAS  Google Scholar 

  239. Aspeslagh S, Li Y, Yu ED, et al. Galactose-modified iNKT cell agonists stabilized by an induced fit of CD1d prevent tumour metastasis. EMBO J. 2011;30:2294–305.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  240. Carreno LJ, Saavedra-Avila NA, Porcelli SA. Synthetic glycolipid activators of natural killer T cells as immunotherapeutic agents. Clin Transl Immunology. 2016;5:e69.

    Article  PubMed  PubMed Central  CAS  Google Scholar 

  241. Schmieg J, Yang G, Franck RW, Tsuji M. Superior protection against malaria and melanoma metastases by a C-glycoside analogue of the natural killer T cell ligand alpha-Galactosylceramide. J Exp Med. 2003;198:1631–41.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  242. Wu TN, Lin KH, Chang YJ, et al. Avidity of CD1d-ligand-receptor ternary complex contributes to T-helper 1 (Th1) polarization and anticancer efficacy. Proc Natl Acad Sci U S A. 2011;108:17275–80.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  243. Schneiders FL, Scheper RJ, von Blomberg BM, et al. Clinical experience with alpha-galactosylceramide (KRN7000) in patients with advanced cancer and chronic hepatitis B/C infection. Clin Immunol. 2011;140:130–41.

    Article  CAS  PubMed  Google Scholar 

  244. Ishikawa A, Motohashi S, Ishikawa E, et al. A phase I study of alpha-galactosylceramide (KRN7000)-pulsed dendritic cells in patients with advanced and recurrent non-small cell lung cancer. Clin Cancer Res. 2005;11:1910–7.

    Article  CAS  PubMed  Google Scholar 

  245. Parekh VV, Lalani S, Kim S, et al. PD-1/PD-L blockade prevents anergy induction and enhances the anti-tumor activities of glycolipid-activated invariant NKT cells. J Immunol. 2009;182:2816–26.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  246. Uldrich AP, Crowe NY, Kyparissoudis K, et al. NKT cell stimulation with glycolipid antigen in vivo: costimulation-dependent expansion, Bim-dependent contraction, and hyporesponsiveness to further antigenic challenge. J Immunol. 2005;175:3092–101.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  247. Chang DH, Osman K, Connolly J, et al. Sustained expansion of NKT cells and antigen-specific T cells after injection of alpha-galactosyl-ceramide loaded mature dendritic cells in cancer patients. J Exp Med. 2005;201:1503–17.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  248. Nieda M, Okai M, Tazbirkova A, et al. Therapeutic activation of Valpha24+Vbeta11+ NKT cells in human subjects results in highly coordinated secondary activation of acquired and innate immunity. Blood. 2004;103:383–9.

    Article  CAS  PubMed  Google Scholar 

  249. Motohashi S, Ishikawa A, Ishikawa E, et al. A phase I study of in vitro expanded natural killer T cells in patients with advanced and recurrent non-small cell lung cancer. Clin Cancer Res. 2006;12:6079–86.

    Article  CAS  PubMed  Google Scholar 

  250. Heczey A, Liu D, Tian G, et al. Invariant NKT cells with chimeric antigen receptor provide a novel platform for safe and effective cancer immunotherapy. Blood. 2014;124:2824–33.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

Download references

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Kenneth DeSantes M.D. .

Editor information

Editors and Affiliations

Rights and permissions

Reprints and permissions

Copyright information

© 2018 Springer International Publishing Switzerland

About this chapter

Check for updates. Verify currency and authenticity via CrossMark

Cite this chapter

DeSantes, K., McDowell, K. (2018). NK Cell and NKT Cell Immunotherapy. In: Gray, J., Marabelle, A. (eds) Immunotherapy for Pediatric Malignancies. Springer, Cham. https://doi.org/10.1007/978-3-319-43486-5_9

Download citation

  • DOI: https://doi.org/10.1007/978-3-319-43486-5_9

  • Published:

  • Publisher Name: Springer, Cham

  • Print ISBN: 978-3-319-43484-1

  • Online ISBN: 978-3-319-43486-5

  • eBook Packages: MedicineMedicine (R0)

Publish with us

Policies and ethics