title: Suppressive activity of regulatory T cells correlates with high CD4(+) T-cell counts and low T-cell activation during chronic simian immunodeficiency virus infection.
abstract: OBJECTIVE
  HIV/simian immunodeficiency virus (SIV) infection is characterized by progressive CD4(+) T-cell depletion and immune exhaustion. CD25(+)FoxP3(+) regulatory T cells were evidenced in HIV/SIV infection and disease. They could be positive by suppressing immune activation during chronic infection and/or damper T-cell immunity. Here we evaluated the correlation between regulatory T-cell function and disease progression in pathogenic SIV infection.
  
  
  METHODS
  We compared the in-vitro suppressive capacity of CD25(+) cells from peripheral blood and peripheral lymph nodes of 18 SIVmac251-infected cynomolgus macaques to look for correlates with biological markers of progression to disease.
  
  
  METHODS
  The in-vitro suppressive capacity of CD25(+) cells was evaluated in a proliferation assay. Ex-vivo T-cell activation was determined by phenotypic labeling followed by flow cytometry.
  
  
  RESULTS
  In chronic infection, CD25(+) regulatory T-cell activity correlated to preserved CD4 T-cell counts and lower T-cell activation.
  
  
  CONCLUSIONS
  This study suggests that regulatory T-cell function is lost during disease progression and may have a positive impact on HIV/SIV disease.
authors.affiliation: CEA, Division of Immuno-Virology, Institute of Emerging Diseases and Innovative Therapies, Fontenay-aux-Roses, France.
authors.forename: Ingrid
authors.initials: I
authors.lastname: Karlsson
authors.forename: Benoît
authors.initials: B
authors.lastname: Malleret
authors.forename: Patricia
authors.initials: P
authors.lastname: Brochard
authors.forename: Benoît
authors.initials: B
authors.lastname: Delache
authors.forename: Julien
authors.initials: J
authors.lastname: Calvo
authors.forename: Roger
authors.initials: R
authors.lastname: Le Grand
authors.forename: Bruno
authors.initials: B
authors.lastname: Vaslin
mesh_terms: D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D018450:Disease Progression; D008213:Lymphocyte Activation / Q000276:immunology*; D008252:Macaca fascicularis; D008297:Male; D016097:Simian Acquired Immunodeficiency Syndrome / Q000276:immunology* / Q000821:virology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*; D019562:Viral Load