title: Activated regulatory T cells suppress effector NK cell responses by an IL-2-mediated mechanism during an acute retroviral infection.
abstract: BACKGROUND
  It is well established that effector T cell responses are crucial for the control of most virus infections, but they are often tightly controlled by regulatory T cells (Treg) to minimize immunopathology. NK cells also contribute to virus control but it is not known if their antiviral effect is influenced by virus-induced Tregs as well. We therefore analyzed whether antiretroviral NK cell functions are inhibited by Tregs during an acute Friend retrovirus infection of mice.
  
  
  RESULTS
  Selective depletion of Tregs by using the transgenic DEREG mouse model resulted in improved NK cell proliferation, maturation and effector cell differentiation. Suppression of NK cell functions depended on IL-2 consumption by Tregs, which could be overcome by specific NK cell stimulation with an IL-2/anti-IL-2 mAb complex.
  
  
  CONCLUSIONS
  The current study demonstrates that virus-induced Tregs indeed inhibit antiviral NK cell responses and describes a targeted immunotherapy that can abrogate the suppression of NK cells by Tregs.
authors.affiliation: Institute of Virology of the University Hospital in Essen, University of Duisburg-Essen, Essen, Germany. elisabeth.littwitz@uni-due.de.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Littwitz-Salomon
authors.affiliation: Institute of Virology of the University Hospital in Essen, University of Duisburg-Essen, Essen, Germany. ilseyar.akhmetzyanova@uni-due.de.
authors.forename: Ilseyar
authors.initials: I
authors.lastname: Akhmetzyanova
authors.affiliation: Institute of Virology of the University Hospital in Essen, University of Duisburg-Essen, Essen, Germany. ceciliavallet@yahoo.de.
authors.forename: Cecilia
authors.initials: C
authors.lastname: Vallet
authors.affiliation: Institute of Virology of the University Hospital in Essen, University of Duisburg-Essen, Essen, Germany. sandra.francois@uk-essen.de.
authors.forename: Sandra
authors.initials: S
authors.lastname: Francois
authors.affiliation: Institute of Virology of the University Hospital in Essen, University of Duisburg-Essen, Essen, Germany. ulf.dittmer@uni-due.de.
authors.forename: Ulf
authors.initials: U
authors.lastname: Dittmer
authors.affiliation: Institute of Virology of the University Hospital in Essen, University of Duisburg-Essen, Essen, Germany. Kathrin.gibbert@uni-due.de.
authors.forename: Kathrin
authors.initials: K
authors.lastname: Gibbert
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D007376:Interleukin-2 / Q000276:immunology* / Q000494:pharmacology; D007694:Killer Cells, Natural / Q000187:drug effects / Q000276:immunology*; D008213:Lymphocyte Activation; D051379:Mice; D008810:Mice, Inbred C57BL; D012190:Retroviridae / Q000276:immunology; D012192:Retroviridae Infections / Q000276:immunology* / Q000821:virology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*
chemical_list: D007376:Interleukin-2