Modulation of host responses is an important strategy by which parasites ensure successful establishment and persistence. Host counteraction against this modulation may be required for the host to develop resistance to infection. In this pilot study, experimental infection of dogs with Echinococcus granulosus induced a strong polarization of the cytokine response towards a Th2 phenotype. Consecutive rounds of infection and cure induced resistance to infection resulting in a dramatically lower parasite burden. Repeatedly-infected resistant dogs also lost immune polarization and developed a balanced Th1/Th2 response. No major differences were observed in the production of regulatory cytokines (IL-10, TGF-β) between dogs with high parasite load and dogs with only few intestinal parasites. These results suggest that E. granulosus-driven immunomodulation contributes to successful infection in the definitive host. This information might be relevant for the development of more effective vaccines against this stage of the parasite.
Bibliographical noteFunding Information:
This work was supported by a project grant from C.S.I.C., Uruguay and the NIAID NIH TMRC grant P01 AI51976, Peru, and FIC Training grant TW001140. AR was supported by a fellowship from PEDECIBA, Facultad de Ciencias, Uruguay. HG is now a Wellcome Trust Senior International Research Fellow. We thank Dr. Seth O’Neal for his help in editing this manuscript.
- Echinococcus granulosus