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Early interferon-gamma ( IFN-γ) release by innate cells is critical to direct type 1 immune response able to control intracellular pathogens like Trypanosoma cruzi. Although CD56bright natural killer ( NK) cells are reported to be potent early IFN-γ producers, other CD56+ cells like CD56dim NK cells and NK-like T cells have recently been shown to also release IFN-γ. We have here studied the contribution of each CD56+ lymphocyte populations in early IFN-γ production in both adults and neonates. On this purpose, we analysed the kinetics of IFN-γ production by RT- PCR, ELISA and flow cytometry from 2 h onwards after T. cruzi and IL-15 stimulation and sought for the responding CD56+ cells. CD56bright and CD56dim CD16− NK cells were the more potent IFN-γ early producers in response to IL-15 and parasites in adults and neonates. In both age groups, the majority of IFN-γ producing cells were NK cells. However, on the contrary to neonates, CD3+ CD56+ NK-like T cells and CD3+ CD56− 'classical' T cells also contributed to early IFN-γ production in adults. Altogether, our results support that whereas NK cells responded almost similarly in neonates and adults, cord blood innate CD56+ and CD56− T cells displayed major quantitative and qualitative defects that could contribute to the well-known neonatal immune immaturity. [ABSTRACT FROM AUTHOR]

We examined the effects of IL-10 on tumour necrosis factor-alpha (TNF-α) and NO production by LPS-activated macrophages and on the ability of these cells to control Trypanosoma cruzi infection. We first observed that the addition of rIL-10 to macrophages of the J774 cell line decreased their synthesis of TNF-α but increased their release of NO in a dose-dependent manner. In parallel, treatment of J774 cells with rIL-10 resulted in a better control of T. cruzi infection involving up-regulation of NO synthesis, as it was not observed in presence of N-nitro-L-arginine methyl ester (L-NAME), a competitive inhibitor of NO synthase. The enhancing effect of rIL-10 on NO production was not observed on peritoneal macrophages from wild-type C57Bl/6 mice, but well on macrophages from IL-10 knock-out mice. The control of NO production by endogenous IL-10 was confirmed by the demonstration that neutralization of IL-10 secreted by LPS-activated macrophages from wild-type mice inhibited their production of NO and, in parallel, their ability to control T. cruzi infection. Taken together, these data demonstrate that both exogenous and endogenous IL-10 up-regulate the production of NO by LPS-activated macrophages and improve thereby their ability to clear T. cruzi infection. [ABSTRACT FROM AUTHOR]

Aim: To model in vitro the contact between adult dental pulp stem cells (DPSCs) and lipoteichoic acid (LTA), a cell wall component expressed at the surface of most Gram‐positive bacteria. Methodology: Human DPSCs obtained from impacted third molars were cultured and exposed to various concentrations of S. aureus LTA (0.1, 1.0 and 10 µg mL−1). The effects of LTA on DPSCs proliferation and apoptosis were investigated by MTT assay and flow cytometry. Mineralization of DPSCs was evaluated by alizarin red staining assay. Migration was investigated by microphotographs of wound‐healing and Transwell migration assays. Reverse transcription polymerase chain reaction was used to examine the effects of LTA on p65 NF‐κB translocation and TLR1, TLR2 or TLR6 regulation. Enzyme‐linked immunosorbent assay was used to investigate LTA‐stimulated DPSCs cytokine production. One‐way or two‐way ANOVA and Tukey post hoc multiple comparison were used for statistical analysis. Results: DPSCs expressed TLR1, TLR2 and TLR6 involved in the recognition of various forms of LTA or lipoproteins. Exposure to LTA did not up‐ or down‐regulate the mRNAs of TLR1, TLR2 or TLR6 whilst LPS acted as a potent inducer of them [TLR1 (P ≤ 0.05), TLR2 (P ≤ 0.001) and TLR6 (P ≤ 0.001)]. Translocation of p65 NF‐κB to the nucleus was detected in LTA‐stimulated cells, but to a lesser extent than LPS‐stimulated DPSCs (P ≤ 0.001). The viability of cells exposed to LTA was greater than unstimulated cells, which was attributed to an increased proliferation and not to less cell death [LTA 1 μg mL−1 (P ≤ 0.001) and 10 μg mL−1 (P ≤ 0.01)]. For specific doses of LTA (1.0 µg mL−1), adhesion of DPSCs to collagen matrix was disturbed (P ≤ 0.05) and cells enhanced their horizontal mobility (P ≤ 0.001). LTA‐stimulated DPSCs released IL‐6 and IL‐8 in a dose‐dependent manner (P ≤ 0.0001). At all concentrations investigated, LTA did not influence osteogenic/odontoblastic differentiation. Conclusions: Human DPSCs were able to sense the wall components of Gram‐positive bacteria likely through TLR2 signalling. Consequently, cells modestly proliferated, increased their migratory behaviour and contributed significantly to the local inflammatory response through cytokine release. [ABSTRACT FROM AUTHOR]

We have developed an experimental model of vaccination against the infection with the protozoa Trypanosoma cruzi, the agent of Chagas disease in Latin America. Vaccination was performed with Trypanosoma rangeli, a non-pathogenic protozoa sharing many antigens with T. cruzi. It strongly protected BALB/c mice, sharply reducing parasitaemia and mortality rate of the acute T. cruzi infection. The aim of the present work was to complete our previous study on the production of IFN-γ and IL-10 in this vaccination model by investigating the production of IL-12p35 and p40, IL-18, TNF, TNF soluble receptors (sTNFR), and nitric oxide (NO), factors known to play a key role in the outcome of T. cruzi infection. We show that the protection obtained against the acute T. cruzi infection was surprisingly associated with reduced circulating levels of IL-18 and NO, whereas the release of IL-12p40 was enhanced in comparison to non-vaccinated infected animals. IL-12p35 remained undetectable in infected animals, vaccinated or not. The balance between sTNFR and TNF suggested a decrease of TNF bioactivity in vaccinated mice. These results show that the protection induced by the vaccination with T. rangeli against a challenging infection with T. cruzi is not associated with the strong type 1 immune response usually involved in the control of intracellular pathogens, particularly questioning the protective role of NO during the acute phase of T. cruzi infection. [Copyright &y& Elsevier]

PROBLEM: To determine if interleukin-16 (IL-16), IL-17, and IL-18 are present at the murine fetomaternal interface during pregnancy as a first step towards investigating their roles in fetomaternal relationship. METHODS: Expression of IL-16, IL-17, and IL-18, was assessed by immunohistochemistry (IHC) in the BALB/c x BALB/k (H2[supd] x H2[supk]), and the CBA/J x BALB/c non-abortion prone, and CBA/J x DBA/2 abortion prone matings. Enzyme-linked immunosorbent assay (ELISA) were performed for the two latter cytokines to compare local production in the abortion prone CBA/J x DBA/2 versus the nonabortion prone CBA/J x BALB/c matings. RESULTS: Expression of IL-17 was borderline. The anti-IL-16 staining specifically localized in the uterine stroma and glandular epithelium and was rather low in the placenta. IL-18 staining started in the peri-implantation uterus in the basal proliferative stroma, and was also traced, although weaker, in the glandular epithelium. In the immediate post-implantation period, a weak stromal staining persisted but there was a strong labeling of the ectoplacental cone. Interestingly, when the ectoplacental cone differentiates into placenta having a major histocompatibility complex (MHC) class I + spongiotrophoblast and a (MHC class I) labyrinth, a very strong transient labeling of uterine natural killer (u-NK) cells was found. Later in gestation, IL-18 was also produced by giant cell and spongiotrophoblast. Finally, we compared by ELISA the production of IL-17/-18 in CBA/J x DBA/2 and CBA/J x BALB/c matings. We detected significantly more IL-18 in the non-abortion prone combination decidua or placenta. CONCLUSION: The... [ABSTRACT FROM AUTHOR]