title: Modifying interleukin-2 concentrations during culture improves function of T cells for adoptive immunotherapy.
abstract: BACKGROUND
  Adoptive immunotherapy with cytotoxic T cells has shown promising clinical results in patients with metastatic melanoma and post-transplant-associated viral infections. Cell transfer therapies often require the ex vivo expansion of large numbers of reactive lymphocytes. Therefore interleukin-2 (IL-2), a potent T-cell mitogenic cytokine that critically affects the features and effectiveness of T cells, is frequently added to cell culture media.
  
  
  METHODS
  We examined the influence of various IL-2 concentrations on cell growth, cytotoxicity, cytokine release and surface marker expression of tumor-infiltrating lymphocytes (TIL) during a standard 14-day rapid expansion phase. The study was conducted under good manufacturing practice (GMP) conditions, using approved reagents in a class 10000 laboratory.
  
  
  RESULTS
  T-cell cultures grown in very high IL-2 concentrations (600-6000 IU/mL) expanded massively and maximally secreted interferon (IFN)-gamma in response to antigenic stimulation, but exhibited only low direct cytotoxicity. On the other hand, TIL cultures grown in low concentrations of IL-2 throughout the rapid expansion phase expanded to a lower extent and barely secreted IFN-gamma but displayed high cytotoxic activity. A combined approach of starting with 10-120 IU/mL IL-2 during the first week, followed by increasing the IL-2 concentration to 6000 IU/mL during the second week, results in T cells that expand well, maximally produce IFN-gamma and are highly cytotoxic against tumor cells.
  
  
  CONCLUSIONS
  Fine tuning of the IL-2 concentration during ex vivo expansion of T cells can yield high numbers of T cells with optimal features for clinical use.
authors.affiliation: Ella Institute of Melanoma, Sheba Medical Center, Tel-Hashomer, Israel. michal.besser@sheba.health.gov.il
authors.forename: M J
authors.initials: MJ
authors.lastname: Besser
authors.forename: E
authors.initials: E
authors.lastname: Schallmach
authors.forename: K
authors.initials: K
authors.lastname: Oved
authors.forename: A J
authors.initials: AJ
authors.lastname: Treves
authors.forename: G
authors.initials: G
authors.lastname: Markel
authors.forename: Y
authors.initials: Y
authors.lastname: Reiter
authors.forename: J
authors.initials: J
authors.lastname: Schachter
mesh_terms: D000943:Antigens, Differentiation / Q000096:biosynthesis; D000951:Antigens, Neoplasm / Q000378:metabolism; D049109:Cell Proliferation; D018920:Coculture Techniques; D003470:Culture Media; D003602:Cytotoxicity, Immunologic; D006801:Humans; D016219:Immunotherapy, Adoptive; D007371:Interferon-gamma / Q000378:metabolism; D007376:Interleukin-2 / Q000276:immunology / Q000378:metabolism*; D008213:Lymphocyte Activation; D016246:Lymphocytes, Tumor-Infiltrating / Q000276:immunology / Q000378:metabolism / Q000473:pathology*; D008545:Melanoma / Q000276:immunology / Q000378:metabolism / Q000473:pathology*; D009362:Neoplasm Metastasis; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology / Q000378:metabolism / Q000473:pathology*
chemical_list: D000943:Antigens, Differentiation; D000951:Antigens, Neoplasm; D003470:Culture Media; D007376:Interleukin-2; D007371:Interferon-gamma