title: Cytokine-induced killer cells for cell therapy of acute myeloid leukemia: improvement of their immune activity by expression of CD33-specific chimeric receptors.
abstract: BACKGROUND
  Cytokine-induced killer cells are ex vivo-expanded cells with potent antitumor activity. The infusion of cytokine-induced killer cells in patients with acute myeloid leukemia relapsing after allogeneic hematopoietic stem cell transplant is well tolerated, but limited clinical responses have been observed. To improve their effector functions against acute myeloid leukemia, we genetically modified cytokine-induced killer cells with chimeric receptors specific for the CD33 myeloid antigen.
  
  
  METHODS
  SFG-retroviral vectors coding for anti-CD33-ζ and anti-CD33-CD28-OX40-ζ chimeric receptors were used to transduce cytokine-induced killer cells. Transduced cells were characterized in vitro for their ability to lyse leukemic targets (4-hour (51)chromium-release and 6-day co-cultures assays on human stromal mesenchymal cells), to proliferate ((3)H-thymidine-incorporation assay) and to secrete cytokines (flow cytomix assay) after contact with acute myeloid leukemia cells. Their activity against normal CD34(+) hematopoietic progenitor cells was evaluated by analyzing the colony-forming unit capacity after co-incubation.
  
  
  RESULTS
  Cytokine-induced killer cells were efficiently transduced with the anti-CD33 chimeric receptors, maintaining their native phenotype and functions and acquiring potent cytotoxicity (up to 80% lysis after 4-hour incubation) against different acute myeloid leukemia targets, as also confirmed in long-term killing experiments. Moreover, introduction of the anti-CD33 chimeric receptors was accompanied by prominent CD33-specific proliferative activity, with the release of high levels of immunostimulatory cytokines. The presence of CD28-OX40 in chimeric receptor endodomain was associated with a significant amelioration of the anti-leukemic activity of cytokine-induced killer cells. Importantly, even though the cytokine-induced killer cells transduced with anti-CD33 chimeric receptors showed toxicity against normal hematopoietic CD34(+) progenitor cells, residual clonogenic activity was preserved.
  
  
  CONCLUSIONS
  Our results indicate that anti-CD33 chimeric receptors strongly enhance anti-leukemic cytokine-induced killer cell functions, suggesting that cytokine-induced killer cells transduced with these molecules might represent a promising optimized tool for acute myeloid leukemia immunotherapy.
authors: Centro Ricerca M. Tettamanti, Clinica Pediatrica Università Milano-Bicocca, Ospedale San Gerardo, Via Pergolesi 33, 20052 Monza (MI), Italy.
authors: Virna
authors: V
authors: Marin
authors: Irene
authors: I
authors: Pizzitola
authors: Valentina
authors: V
authors: Agostoni
authors: Greta Maria Paola Giordano
authors: GM
authors: Attianese
authors: Helene
authors: H
authors: Finney
authors: Alastair
authors: A
authors: Lawson
authors: Martin
authors: M
authors: Pule
authors: Raphael
authors: R
authors: Rousseau
authors: Andrea
authors: A
authors: Biondi
authors: Ettore
authors: E
authors: Biagi
mesh_terms: D000208:Acute Disease; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D064987:Cell- and Tissue-Based Therapy / Q000379:methods*; D002478:Cells, Cultured; D002648:Child; D018920:Coculture Techniques; D055612:Cytokine-Induced Killer Cells / Q000166:cytology / Q000276:immunology* / Q000378:metabolism; D003602:Cytotoxicity, Immunologic / Q000276:immunology; D005434:Flow Cytometry; D057809:HEK293 Cells; D018922:HL-60 Cells; D006801:Humans; D007951:Leukemia, Myeloid / Q000276:immunology / Q000473:pathology / Q000628:therapy*; D018160:Receptors, Cytoplasmic and Nuclear / Q000235:genetics / Q000276:immunology; D011993:Recombinant Fusion Proteins / Q000276:immunology; D063268:Sialic Acid Binding Ig-like Lectin 3 / Q000276:immunology; D013997:Time Factors
chemical_list: D018160:Receptors, Cytoplasmic and Nuclear; D011993:Recombinant Fusion Proteins; D063268:Sialic Acid Binding Ig-like Lectin 3