title: Depleting anti-CD4 monoclonal antibody (GK1.5) treatment: influence on regulatory CD4+CD25+Foxp3+ T cells in mice.
abstract: BACKGROUND
  CD4(+)CD25(+) regulatory T (Treg) cells are often essential for the maintenance of immunologic self-tolerance and transplant tolerance in some cases. The effects of depleting anti-CD4 monoclonal antibody (GK1.5), which was used in transplant tolerance induction, on CD4(+)CD25(+) Treg cells have not been investigated.
  
  
  METHODS
  Three weeks after BALB/c mice were injected with GK1.5 or phosphate-buffered saline, the levels, phenotype and immunosuppressive function of CD4(+)CD25(+) Treg cells in these mice were detected.
  
  
  RESULTS
  The numbers of CD4 and CD4(+)CD25(+) Treg cells in the periphery were markedly decreased in GK1.5-treated mice. However, GK1.5 treatment significantly enhanced the ratios of CD4(+)CD25(+) T cells or CD4(+)CD25(+)Foxp3 T cells to CD4(+) T cells in the periphery (P<0.01). Compared with the control mice, more CD4(+)CD25(+) T cells in GK1.5-treated mice showed CD45RB and CD62L phenotype. Furthermore, enriched CD4(+)CD25(+) Treg cells in GK1.5-treated mice show immunosuppressive ability on the immune response of T effector cells to alloantigens or mitogen as efficiently as those from the control mice in vitro.
  
  
  CONCLUSIONS
  GK1.5 could significantly enhance the percentage of CD4(+)CD25(+)Foxp3(+) Treg cells in the periphery while keeping these cells functional, indicating that GK1.5 might affect the potential induction of immune tolerance by different influences on CD4(+)CD25(+)Treg cells and CD4(+)CD25(-) T cells in periphery.
authors.affiliation: Institute of Zoology, Chinese Academy of Sciences, Beijing, China.
authors.forename: Huanfa
authors.initials: H
authors.lastname: Yi
authors.forename: Yu
authors.initials: Y
authors.lastname: Zhen
authors.forename: Chun
authors.initials: C
authors.lastname: Zeng
authors.forename: Lianjun
authors.initials: L
authors.lastname: Zhang
authors.forename: Yong
authors.initials: Y
authors.lastname: Zhao
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology*; D005260:Female; D051858:Forkhead Transcription Factors / Q000032:analysis / Q000502:physiology*; D016130:Immunophenotyping; D019041:L-Selectin / Q000032:analysis; D017493:Leukocyte Common Antigens / Q000032:analysis; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D050378:T-Lymphocytes, Regulatory / Q000276:immunology / Q000502:physiology*
chemical_list: D000911:Antibodies, Monoclonal; D051858:Forkhead Transcription Factors; C498833:Foxp3 protein, mouse; C106577:monoclonal antibody GK1.5; D019041:L-Selectin; D017493:Leukocyte Common Antigens