title: Streptamer-based selection of WT1-specific CD8+ T cells for specific donor lymphocyte infusions.
abstract: OBJECTIVE
  Donor lymphocyte infusions may generate a desirable graft-versus-leukemia effect, but also elicit a noxious graft-versus-host disease. A positive selection of leukemia (antigen)-specific T cells would be highly desirable. In this study, we focused on the immunogenic leukemia antigen Wilms' Tumor gene 1 (WT1).
  
  
  METHODS
  We employed the technology of streptamers available at good manufacturing practice level to first determine the frequency of human leukocyte antigen-A2 restricted WT1-specific CD8(+) T cells. Then, specific cells were labeled with streptamers and selected by magnetic cell separation. Purity and immunophenotype of selected cells were analyzed.
  
  
  RESULTS
  Twenty-one of 40 healthy donors had naïve WT1-specific CD8(+) T-cell frequencies of >0.5%, and 8 of 40 even >1.0% of all CD8(+) T cells. In 7 of 10 acute myeloid leukemia patients, the frequencies were 0.5% to 3.65%. After positive selection by magnetic cell separation, a 60-fold increase with a purity of up to 17.79% in the lymphocyte gate and 86.18% in the CD8(+) T-cell gate could be achieved for CD8(+)WT1 streptamer(+)CD28(+/-)CD45RA(+)CCR7(-) effector T cells.
  
  
  CONCLUSIONS
  Streptamer technology allows selection of pure WT1-specific effector T cells. This is a prerequisite for clinical applications targeting tumor-specific antigens, such as adoptive T-cell transfer.
authors.affiliation: Department of Internal Medicine III, University of Rostock, Rostock, Germany.
authors.forename: Xinchao
authors.initials: X
authors.lastname: Wang
authors.forename: Anita
authors.initials: A
authors.lastname: Schmitt
authors.forename: Baoan
authors.initials: B
authors.lastname: Chen
authors.forename: Xun
authors.initials: X
authors.lastname: Xu
authors.forename: Jiju
authors.initials: J
authors.lastname: Mani
authors.forename: Michael
authors.initials: M
authors.lastname: Linnebacher
authors.forename: Mathias
authors.initials: M
authors.lastname: Freund
authors.forename: Michael
authors.initials: M
authors.lastname: Schmitt
mesh_terms: D000208:Acute Disease; D019264:Adoptive Transfer / Q000379:methods; D001782:Blood Donors; D018106:CD28 Antigens / Q000276:immunology / Q000378:metabolism; D018414:CD8-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology* / Q000378:metabolism; D002469:Cell Separation / Q000379:methods; D005434:Flow Cytometry; D015789:HLA-A2 Antigen / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D006801:Humans; D016130:Immunophenotyping; D007951:Leukemia, Myeloid / Q000097:blood; D017493:Leukocyte Common Antigens / Q000276:immunology / Q000378:metabolism; D008280:Magnetics; D054400:Receptors, CCR7 / Q000276:immunology / Q000378:metabolism; D025721:WT1 Proteins / Q000235:genetics / Q000276:immunology*
chemical_list: C515370:CCR7 protein, human; D018106:CD28 Antigens; D015789:HLA-A2 Antigen; D054400:Receptors, CCR7; D025721:WT1 Proteins; D017493:Leukocyte Common Antigens