title: IFN-γ plays a unique role in protection against low virulent Trypanosoma cruzi strain.
abstract: BACKGROUND
  T. cruzi strains have been divided into six discrete typing units (DTUs) according to their genetic background. These groups are designated T. cruzi I to VI. In this context, amastigotes from G strain (T. cruzi I) are highly infective in vitro and show no parasitemia in vivo. Here we aimed to understand why amastigotes from G strain are highly infective in vitro and do not contribute for a patent in vivo infection.
  
  
  RESULTS
  Our in vitro studies demonstrated the first evidence that IFN-γ would be associated to the low virulence of G strain in vivo. After intraperitoneal amastigotes inoculation in wild-type and knockout mice for TNF-α, Nod2, Myd88, iNOS, IL-12p40, IL-18, CD4, CD8 and IFN-γ we found that the latter is crucial for controlling infection by G strain amastigotes.
  
  
  CONCLUSIONS
  Our results showed that amastigotes from G strain are highly infective in vitro but did not contribute for a patent infection in vivo due to its susceptibility to IFN-γ production by host immune cells. These data are useful to understand the mechanisms underlying the contrasting behavior of different T. cruzi groups for in vitro and in vivo infection.
authors.affiliation: Instituto de Ciências Biomédicas, Universidade Federal de Uberlândia, Uberlândia, Minas Gerais, Brazil.
authors.forename: Adele A
authors.initials: AA
authors.lastname: Rodrigues
authors.forename: Jasson S S
authors.initials: JS
authors.lastname: Saosa
authors.forename: Grace K
authors.initials: GK
authors.lastname: da Silva
authors.forename: Flávia A
authors.initials: FA
authors.lastname: Martins
authors.forename: Aline A
authors.initials: AA
authors.lastname: da Silva
authors.forename: Cecílio P da Silva
authors.initials: CP
authors.lastname: Souza Neto
authors.forename: Catarina V
authors.initials: CV
authors.lastname: Horta
authors.forename: Dario S
authors.initials: DS
authors.lastname: Zamboni
authors.forename: João S
authors.initials: JS
authors.lastname: da Silva
authors.forename: Eloisa A V
authors.initials: EA
authors.lastname: Ferro
authors.forename: Claudio V
authors.initials: CV
authors.lastname: da Silva
mesh_terms: D000818:Animals; D014355:Chagas Disease / Q000276:immunology*; D005260:Female; D007371:Interferon-gamma / Q000276:immunology*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D018512:Parasitemia / Q000276:immunology / Q000517:prevention & control; D014349:Trypanosoma cruzi / Q000276:immunology* / Q000472:pathogenicity
chemical_list: D007371:Interferon-gamma