title: Regulatory T-cell depletion does not prevent emergence of new CD25+ FOXP3+ lymphocytes after antigen stimulation in culture.
abstract: BACKGROUND
  The removal of human regulatory T (T(reg)) cells from a cellular product prior to the induction of a T-cell response has the potential to boost the total yield of antigen (Ag)-specific CD4(+) and CD8(+) T cells.
  
  
  METHODS
  We examined the effect of this manipulation on the generation of human anti-cytomegalovirus (CMV) T-cell responses. Furthermore, we examined the clonotypic composition of Ag-specific CD4(+)FOXP3(+) and CD4(+)FOXP3(-) T cells.
  
  
  RESULTS
  We found that the immunomagnetic depletion of CD25(+) cells had an unpredictable effect on outcome, with total yields of CMV-specific T cells either increasing or decreasing after the removal of these cells. The depletion of CD25(+) cells both removed a proportion of Ag-specific T cells and failed to eliminate a substantial population of T(reg) cells. Furthermore, using a novel T-cell receptor clonotyping technique, we found that Ag recognition induces the expression of FOXP3 in a proportion of specific T cells; these FOXP3-expressing Ag-specific CD4(+) and CD8(+) T cells were no longer capable of producing inflammatory cytokines.
  
  
  CONCLUSIONS
  The depletion of CD25(+) cells from the starting population has a variable effect on the total yield of Ag-specific T cells, a proportion of which invariably acquire FOXP3 expression and lose effector function.
authors: Hematology Branch, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892-1202, USA. melenhoj@nhlbi.nih.gov
authors: J J
authors: JJ
authors: Melenhorst
authors: P
authors: P
authors: Scheinberg
authors: J
authors: J
authors: Lu
authors: D R
authors: DR
authors: Ambrozak
authors: E
authors: E
authors: Sosa
authors: L
authors: L
authors: Zhao
authors: N F
authors: NF
authors: Hensel
authors: B N
authors: BN
authors: Savani
authors: D C
authors: DC
authors: Douek
authors: D A
authors: DA
authors: Price
authors: A J
authors: AJ
authors: Barrett
mesh_terms: D000941:Antigens / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000187:drug effects / Q000276:immunology; D002478:Cells, Cultured; D002999:Clone Cells; D000939:Epitopes; D051858:Forkhead Transcription Factors / Q000378:metabolism*; D006801:Humans; D016130:Immunophenotyping; D007371:Interferon-gamma / Q000276:immunology; D053645:Interleukin-2 Receptor alpha Subunit / Q000378:metabolism*; D008213:Lymphocyte Activation; D008212:Lymphocyte Depletion; D008934:Mitogens / Q000494:pharmacology; D010750:Phosphoproteins / Q000378:metabolism; D050378:T-Lymphocytes, Regulatory / Q000276:immunology* / Q000378:metabolism*; D014763:Viral Matrix Proteins / Q000378:metabolism
chemical_list: D000941:Antigens; D000939:Epitopes; C418974:FOXP3 protein, human; D051858:Forkhead Transcription Factors; D053645:Interleukin-2 Receptor alpha Subunit; D008934:Mitogens; D010750:Phosphoproteins; D014763:Viral Matrix Proteins; C065418:cytomegalovirus matrix protein 65kDa; D007371:Interferon-gamma