title: Role of CD4+ Foxp3+ Regulatory T Cells in Protection Induced by a Live Attenuated, Replicating Type I Vaccine Strain of Toxoplasma gondii.
abstract: Vaccination with the live attenuated Toxoplasma gondii Mic1.3KO strain induced long-lasting immunity against challenge with Toxoplasma gondii type I and type II strains. The involvement of regulatory T cells (Tregs) in the protection mechanism was investigated. Intraperitoneal injection of Mic1.3KO induced a weak and transient influx of CD4(+) Foxp3(+) T regulatory cells followed by recruitment/expansion of CD4(+) Foxp3(-) CD25(+) effector cells and control of the parasite at the site of infection. The local and systemic cytokine responses associated with this recruitment of Tregs were of the TH1/Treg-like type. In contrast, injection of RH, the wild-type strain from which the vaccinal strain is derived, induced a low CD4(+) Foxp3(+) cell influx and uncontrolled multiplication of the parasites at this local site, followed by death of the mice. The associated local and systemic cytokine responses were of the TH1/TH17-like type. In addition, in vivo Treg induction in RH-infected mice with interleukin-2 (IL-2)/anti-IL-2 complexes induced control of the parasite and a TH1/Treg cytokine response similar to the response after Mic1.3KO vaccination. These results suggest that Tregs may contribute to the protective response after vaccination with Mic1.3KO.
authors.affiliation: Université de Tours, UMR1282 Infectiologie et Santé Publique, Tours, France, and INRA, UMR1282 Infectiologie et Santé Publique, Nouzilly, France.
authors.forename: Haroon
authors.initials: H
authors.lastname: Akbar
authors.affiliation: Université de Tours, UMR1282 Infectiologie et Santé Publique, Tours, France, and INRA, UMR1282 Infectiologie et Santé Publique, Nouzilly, France.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Dimier-Poisson
authors.affiliation: Université de Tours, UMR1282 Infectiologie et Santé Publique, Tours, France, and INRA, UMR1282 Infectiologie et Santé Publique, Nouzilly, France nathalie.moire@univ-tours.fr.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Moiré
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D005260:Female; D051379:Mice; D008810:Mice, Inbred C57BL; D016052:Protozoan Vaccines / Q000276:immunology*; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*; D014122:Toxoplasma / Q000276:immunology; D014123:Toxoplasmosis / Q000276:immunology*
chemical_list: D016052:Protozoan Vaccines