Horizon 1 1 17 ACL : Articles dans des revues avec comité de lecture répertoriées par l'AERES Parasitology 109-119 Trypanosoma cruzi genotype immunopathology virulence mouse 2005 fdi:010041532 ENG Parasitology 0031-1820 ISI:000231004500012 Part 1 10.1017/S003118200400722X https://www.documentation.ird.fr/hor/fdi:010041532 131 Horizon (IRD) Immunopathology of Chagas' disease in Balb/c mice infected with 2 Trypanosoma cruzi clones, belonging to the T. cruzi I lineage and presenting different in vitro virulence (P/209 ell > SO34 c14) was compared. In the acute phase, evading mechanisms such as parasite-induced lymphocyte polyclonal activation and T cell immunosuppression were higher in mice infected with the clone giving a higher parasitaemia (P/209 c11). A similar increase of non-specific isotypes was observed in both infections with IgG2a prevalence. Interestingly, CD8+ cell hypercellularity and lymphocyte immunosuppression were observed during the chronic phase (245 days post-infection) in mice infected by the most virulent clone. In the same way, the parasite-specific antibody response was more intense in P/209 c11-infected mice over the acute phase. During the chronic phase this response remarkably dropped down in SO34 c14-infected mice exclusively. Finally, P/209 ell-infected mice presented a more severe inflammation and tissue damage in heart and quadriceps than SO34 c14-infected mice. This comparative study showed differences between the two clones: a higher virulence in vivo being clearly associated with a greater ability to induce evasion mechanisms and severe tissue damage. 052