Leishmania (Leishmania) amazonensis Infection in Mice Treated With FTY720

Lopes, Camila Takáo; Paula, Daisy Maria Bentes de; Cury, Patrí­cia Maluf; Valero-Lapchik, Valderez Bastos; Bueno, Valquíria

doi:10.1016/j.transproceed.2010.01.026

Cited by 2 publications

(1 citation statement)

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“…infections [34][35][36]. The precise reasons for these divergent responses are not clear but probably reflect differences in the priming sites as well as, the immunopathologies caused by the different infectious agents.…”

Section: Discussionmentioning

confidence: 99%

Re-circulation of lymphocytes mediated by sphingosine-1-phosphate receptor-1 contributes to resistance against experimental infection with the protozoan parasite Trypanosoma cruzi

Dominguez

Ersching

Lemos

et al. 2012

Vaccine

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T-cell mediated immune responses are critical for acquired immunity against infection by the intracellular protozoan parasite Trypanosoma cruzi. Despite its importance, it is currently unknown where protective T cells are primed and whether they need to re-circulate in order to exert their anti-parasitic effector functions. Here, we show that after subcutaneous challenge, CD11c(+)-dependent specific CD8(+) T-cell immune response to immunodominant parasite epitopes arises almost simultaneously in the draining lymph node (LN) and the spleen. However, until day 10 after infection, we observed a clear upregulation of activation markers only on the surface of CD11C(+)PDCA1(+) cells present in the LN and not in the spleen. Therefore, we hypothesized that CD8(+) T cells re-circulated rapidly from the LN to the spleen. We investigated this phenomenon by administering FTY720 to T. cruzi-infected mice to prevent egress of T cells from the LN by interfering specifically with signalling through sphingosine-1-phosphate receptor-1. In T. cruzi-infected mice receiving FTY720, CD8 T-cell immune responses were higher in the draining LN and significantly reduced in their spleen. Most importantly, FTY720 increased susceptibility to infection, as indicated by elevated parasitemia and accelerated mortality. Similarly, administration of FTY720 to mice genetically vaccinated with an immunodominant parasite antigen significantly reduced their protective immunity, as observed by the parasitemia and survival of vaccinated mice. We concluded that re-circulation of lymphocytes mediated by sphingosine-1-phosphate receptor-1 greatly contributes to acquired and vaccine-induced protective immunity against experimental infection with a human protozoan parasite.

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Section: Discussionmentioning

confidence: 99%