Premium
Induction of immune tolerance through an IL‐10 dependent mechanism allows Entamoeba histolytica successful cololization in the colon
Author(s) -
Rybicka Joanna Malgorzata,
Chadee Kris
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.320.8
Subject(s) - entamoeba histolytica , immune system , antigen , biology , apoptosis , population , immune tolerance , immunology , microbiology and biotechnology , medicine , biochemistry , environmental health
Entamoeba histolytica infects 10% of the world's population, which can lead to amoebic dysentery and/or liver abscess. The majority of infected individuals are completely asymptomatic. We hypothesized that E. histolytica is capable of inducing immune tolerance in antigen presenting cells thus promoting parasite survival in the colon in the absence of an overt inflammatory or immune response. In support of this, we show that dendritic cells (DC's) and macrophages (mφ) exposed to amoeba secreted proteins can induce a significantly up‐regulation of IL‐10 mRNA expression and increase phosphorylation of ILT2. Furthermore, low concentrations (10μg/mL) of amoebic proteins caused rapid 3–8‐fold up‐regulation of ILT2 inhibitory receptor on CD4 + T cells in the presence of mφ or DCs 36 h following exposure. However, there was no significant up‐regulation of ILT2 if T cells were deficient in IL‐10. Moreover, amoebic proteins caused a significantly increased in apoptosis in IL‐10 deficient T cells after 48 or 72 hr as compared to wild type controls. We conclude that E. histolytica is capable of inducing IL‐10 production in antigen presenting cells, which is required for up‐regulating ILT2 on CD4 + T cells and inhibition of T cells apoptosis. This work was supported by NSERC. JMR is a recepient of the QE II Graduate Scholarship from the Province of Alberta and CAG/CIHR studentship.