Role of CD4+Foxp3+ regulatory T cells in protection induced by a live, attenuated, replicating Type-I vaccine strain of Toxoplasma

Infect Immun. 2015 Jun 29. pii: IAI.00217-15. [Epub ahead of print]

 

Akbar H¹, Dimier-Poisson I¹, Moiré N².

 

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 T regulatory (Treg) cells 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 Treg were of 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 TH1/TH17-like type.In addition, in vivo Treg induction in the RH-infected mice with IL2/anti-IL2 complexes induced control of the parasite and a TH1/Treg cytokine response similar to the response after Mic1.3KO vaccination. These results suggest that Treg cells may contribute to the protective response after vaccination with Mic1.3KO.
Copyright © 2015, American Society for Microbiology. All Rights Reserved.

PMID:

26123802

[PubMed - as supplied by publisher]