title: IRX-2, a novel immunotherapeutic, enhances and protects NK-cell functions in cancer patients.
abstract: BACKGROUND
  IRX-2 is a primary biologic which has been used for the therapy of head and neck squamous cell cancer (HNSCC) with promising clinical results. Since NK-cell function is compromised in HNSCC patients, we tested the effects of IRX-2 on the restoration of human NK-cell functions in vitro.
  
  
  METHODS
  Peripheral blood mononuclear cells (PBMC) were isolated from 23 HNSCC patients and 10 normal controls (NC). The NK-cell phenotype and functions were compared before and after culture ± IRX-2 or ± 50 IU/ml rhIL-2. Flow cytometry was used to study the NK-cell phenotype, cytotoxic activity and cytokine expression.
  
  
  RESULTS
  Impaired NK-cell cytotoxicity in HNSCC patients was related to lower expression of NKG2D, NKp30 and NKp46 receptors (P < 0.05) and not to a decreased frequency of NK cells. Incubation of patients' NK cells with IRX-2 up-regulated the percentage of receptor-positive NK cells (P < 0.05). It also up-regulated cytotoxicity of patients' NK cells (P < 0.01) more effectively than rhIL-2 (P < 0.01). IRX-2, but not rhIL-2, protected NK cells from suppression mediated by TGF-β, and it restored (P < 0.05) expression of activating NK-cell receptors and NK-cell cytotoxicity suppressed by TGF-β. Expression of pSMAD was decreased in NK cells treated with IRX-2 but not in those treated with rhIL-2.
  
  
  CONCLUSIONS
  IRX-2 was more effective than IL-2 in enhancing NK-cell cytotoxicity and protecting NK-cell function of HNSCC patients in vitro, emphasizing the potential advantage of IRX-2 as a component of future therapies for HNSCC.
authors.affiliation: Department of Pathology, University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: B
authors.initials: B
authors.lastname: Schilling
authors.forename: E S
authors.initials: ES
authors.lastname: Halstead
authors.forename: P
authors.initials: P
authors.lastname: Schuler
authors.forename: M
authors.initials: M
authors.lastname: Harasymczuk
authors.forename: J E
authors.initials: JE
authors.lastname: Egan
authors.forename: T L
authors.initials: TL
authors.lastname: Whiteside
mesh_terms: D002294:Carcinoma, Squamous Cell / Q000097:blood / Q000276:immunology* / Q000628:therapy; D016207:Cytokines / Q000276:immunology / Q000494:pharmacology*; D003602:Cytotoxicity, Immunologic / Q000187:drug effects / Q000276:immunology; D005434:Flow Cytometry; D006258:Head and Neck Neoplasms / Q000097:blood / Q000276:immunology* / Q000628:therapy; D006801:Humans; D007167:Immunotherapy; D007376:Interleukin-2 / Q000276:immunology / Q000494:pharmacology; D020014:K562 Cells; D007694:Killer Cells, Natural / Q000187:drug effects* / Q000276:immunology*; D007963:Leukocytes, Mononuclear / Q000187:drug effects / Q000276:immunology; D055655:NK Cell Lectin-Like Receptor Subfamily K / Q000096:biosynthesis / Q000276:immunology; D055627:Natural Cytotoxicity Triggering Receptor 1 / Q000096:biosynthesis / Q000276:immunology; D055628:Natural Cytotoxicity Triggering Receptor 3 / Q000096:biosynthesis / Q000276:immunology; D010766:Phosphorylation / Q000187:drug effects; D051785:Smad Proteins / Q000096:biosynthesis / Q000276:immunology; D053773:Transforming Growth Factor beta1 / Q000276:immunology / Q000494:pharmacology; D015854:Up-Regulation / Q000187:drug effects / Q000276:immunology
chemical_list: D016207:Cytokines; C114857:IRX 2; D007376:Interleukin-2; C527085:KLRK1 protein, human; C112260:NCR1 protein, human; C431710:NCR3 protein, human; D055655:NK Cell Lectin-Like Receptor Subfamily K; D055627:Natural Cytotoxicity Triggering Receptor 1; D055628:Natural Cytotoxicity Triggering Receptor 3; D051785:Smad Proteins; D053773:Transforming Growth Factor beta1