title: Efficient generation of gene-modified human natural killer cells via alpharetroviral vectors.
abstract: Natural killer (NK) cells play an important role in tumor immunotherapy with their unique capability of killing transformed cells without the need for prior sensitization and without major histocompatibility complex (MHC)/peptide restriction. However, tumor cells can escape NK cell cytotoxicity by various tumor immune escape mechanisms. To overcome these escape mechanisms, NK cells can be modified to express chimeric antigen receptors (CARs), enhancing their tumor-specific cytotoxicity. To determine the most efficacious method to modify human NK cells, we compared different retroviral vector systems, retroviral pseudotypes, and transduction protocols. Using optimized transduction conditions, the highest transduction levels (up to 60%) were achieved with alpharetroviral vectors. Alpharetroviral-modified primary human NK cells exhibited no alteration in receptor expression and had similar degranulation activity as untransduced NK cells, thus demonstrating that alpharetroviral modification did not negatively affect NK cell cytotoxicity. Transduction of NK cells with an alpharetroviral vector containing a CD19 CAR expression cassette selectively enhanced NK cell cytotoxicity towards CD19-expressing leukemia cells, achieving nearly complete elimination of leukemia cells after 48 h. Taken together, alpharetroviral vectors are promising tools for NK cell-mediated cancer immunotherapy applications.
  
  
  CONCLUSIONS
  Efficient modification of human NK cells using alpharetroviral vectors. Anti-CD19-CAR-NK cells exhibited improved cytotoxicity towards CD19(+) leukemia cells. Alpharetroviral vectors are promising tools for immunotherapy applications using NK cells.
authors: Institute of Experimental Hematology, Hannover Medical School, 30625, Hannover, Germany.
authors: Julia D
authors: JD
authors: Suerth
authors: Institute of Experimental Hematology, Hannover Medical School, 30625, Hannover, Germany.
authors: Michael A
authors: MA
authors: Morgan
authors: Institute of Cellular Therapeutics, IFB-Tx, Hannover Medical School, 30625, Hannover, Germany.
authors: Stephan
authors: S
authors: Kloess
authors: Institute of Experimental Hematology, Hannover Medical School, 30625, Hannover, Germany.
authors: Dirk
authors: D
authors: Heckl
authors: Institute of Transplant Immunology, IFB-Tx, Hannover Medical School, 30625, Hannover, Germany.
authors: Christine
authors: C
authors: Neudörfl
authors: Institute of Transplant Immunology, IFB-Tx, Hannover Medical School, 30625, Hannover, Germany.
authors: Christine S
authors: CS
authors: Falk
authors: Institute of Cellular Therapeutics, IFB-Tx, Hannover Medical School, 30625, Hannover, Germany.
authors: Ulrike
authors: U
authors: Koehl
authors: Institute of Experimental Hematology, Hannover Medical School, 30625, Hannover, Germany. schambach.axel@mh-hannover.de.|Division of Hematology/Oncology, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA. schambach.axel@mh-hannover.de.
authors: Axel
authors: A
authors: Schambach
mesh_terms: D001355:Alpharetrovirus / Q000235:genetics*; D018941:Antigens, CD19 / Q000235:genetics*; D045744:Cell Line, Tumor; D003602:Cytotoxicity, Immunologic / Q000235:genetics* / Q000276:immunology; D015316:Genetic Therapy / Q000379:methods; D005822:Genetic Vectors / Q000235:genetics*; D049452:Green Fluorescent Proteins / Q000235:genetics; D006801:Humans; D016219:Immunotherapy, Adoptive / Q000379:methods; D007694:Killer Cells, Natural / Q000166:cytology / Q000276:immunology*; D007938:Leukemia / Q000276:immunology / Q000628:therapy*; D011946:Receptors, Antigen / Q000096:biosynthesis / Q000235:genetics* / Q000276:immunology; D014161:Transduction, Genetic / Q000379:methods; D019139:Tumor Escape / Q000276:immunology
chemical_list: D018941:Antigens, CD19; D011946:Receptors, Antigen; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins
keywords: Alpharetrovirus; Chimeric antigen receptor; Gene therapy; Immunotherapy; Leukemia; Natural killer cells