title: Depletion of alloreactive T cells via CD69: implications on antiviral, antileukemic and immunoregulatory T lymphocytes.
abstract: Selective depletion of alloreactive T cells from stem-cell allografts should abrogate graft-versus-host disease while preserving beneficial T cell specificities to facilitate engraftment and immune reconstitution. We therefore explored a refined immunomagnetic separation strategy to effectively deplete alloreactive donor lymphocytes expressing the activation antigen CD69 upon stimulation, and examined the retainment of antiviral, antileukemic, and immunoregulatory T cells. In addition to the CD69high T cell fraction, our studies retrieved two T cell subsets based on residual CD69 expression. Whereas, truly CD69(neg) cells were devoid of detectable alloresponses to original stimulators, CD69-low (CD69low)-expressing T cells elicited significant residual alloreactivity upon restimulation. In interferon-gamma enzyme linked immunospot assays, anti-cytomegalovirus and anti-Epstein-Barr virus responses were preserved at significant numbers among CD69neg T lymphocytes. Accordingly, T cells recognizing the leukemia-associated Wilm's tumor-1 antigen were still detectable in the CD69neg subset. However, antiviral and antileukemic specificities were also consistently found within CD69low T cells, suggesting that memory-type donor T cells were partially captured due to residual CD69 expression. Finally, CD4+CD25+ Foxp3+ immunoregulatory T cells did not upregulate CD69 upon allogeneic stimulation. Our data suggest that CD69-mediated removal of alloreactivity can result in efficient allodepletion, but may partially affect the persistence of antiviral and antileukemic donor memory specificities captured among CD69low-expressing lymphocytes.
authors.affiliation: Department of Medicine III--Hematology and Oncology, Johannes Gutenberg-University School of Medicine, Mainz, Germany. uhartwig@mail.uni-mainz.de
authors.forename: U F
authors.initials: UF
authors.lastname: Hartwig
authors.forename: M
authors.initials: M
authors.lastname: Nonn
authors.forename: S
authors.initials: S
authors.lastname: Khan
authors.forename: R G
authors.initials: RG
authors.lastname: Meyer
authors.forename: C
authors.initials: C
authors.lastname: Huber
authors.forename: W
authors.initials: W
authors.lastname: Herr
mesh_terms: D015703:Antigens, CD / Q000276:immunology*; D000945:Antigens, Differentiation, T-Lymphocyte / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D002352:Carrier Proteins / Q000276:immunology; D018797:Cell Cycle Proteins; D002460:Cell Line; D003587:Cytomegalovirus / Q000276:immunology*; D003586:Cytomegalovirus Infections / Q000209:etiology / Q000276:immunology; D004268:DNA-Binding Proteins / Q000276:immunology; D020031:Epstein-Barr Virus Infections / Q000209:etiology / Q000276:immunology; D051858:Forkhead Transcription Factors / Q000276:immunology; D006086:Graft vs Host Disease / Q000150:complications / Q000276:immunology; D018380:Hematopoietic Stem Cell Transplantation; D004854:Herpesvirus 4, Human / Q000276:immunology*; D006801:Humans; D007156:Immunologic Memory / Q000276:immunology; D037181:Lectins, C-Type; D008213:Lymphocyte Activation / Q000276:immunology; D008212:Lymphocyte Depletion / Q000379:methods; D009687:Nuclear Proteins / Q000276:immunology; D000072260:RNA Splicing Factors; D015375:Receptors, Interleukin-2 / Q000276:immunology; D014184:Transplantation, Homologous; D000099192:CD69 Antigens
chemical_list: D015703:Antigens, CD; D000945:Antigens, Differentiation, T-Lymphocyte; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D051858:Forkhead Transcription Factors; D037181:Lectins, C-Type; D009687:Nuclear Proteins; D000072260:RNA Splicing Factors; D015375:Receptors, Interleukin-2; D000099192:CD69 Antigens; C418974:FOXP3 protein, human; C419554:WTAP protein, human