Interferon-α Improves Phosphoantigen-Induced Vγ9Vδ2 T-Cells Interferon-γ Production during Chronic HCV Infection

In chronic HCV infection, treatment failure and defective host immune response highly demand improved therapy strategies. Vγ9Vδ2 T-cells may inhibit HCV replication in vitro through IFN-γ release after Phosphoantigen (PhAg) stimulation. The aim of our work was to analyze Vγ9Vδ2 T-cell functionality during chronic HCV infection, studying the role of IFN-α on their function capability. IFN-γ production by Vγ9Vδ2 T-cells was analyzed in vitro in 24 HCV-infected patients and 35 healthy donors (HD) after PhAg stimulation with or without IFN-α. The effect of in vivo PhAg/IFN-α administration on plasma IFN-γ levels was analyzed in M. fascicularis monkeys. A quantitative analysis of IFN-γ mRNA level and stability in Vγ9Vδ2 T-cells was also evaluated. During chronic HCV infection, Vγ9Vδ2 T-cells showed an effector/activated phenotype and were significantly impaired in IFN-γ production. Interestingly, IFN-α was able to improve their IFN-γ response to PhAg both in vitro in HD and HCV-infected patients, and in vivo in Macaca fascicularis primates. Finally, IFN-α increased IFN-γ-mRNA transcription and stability in PhAg-activated Vγ9Vδ2 T-cells. Altogether our results show a functional impairment of Vγ9Vδ2 T-cells during chronic HCV infection that can be partially restored by using IFN-α. A study aimed to evaluate the antiviral impact of PhAg/IFN-α combination may provide new insight in designing possible combined strategies to improve HCV infection treatment outcome

Microbial successions during wastewater treatment start-up using microalgae

International audienc

Importance of ecological interactions during wastewater treatment using High Rate Algal Ponds under different temperate climates

International audienceSeveral studies focused on wastewater treatment in High Rate Algal Ponds (HRAP) suggest that highly variable climatic conditions cause large variations of microalgal biomass productivity. In the present study, we show that similar carbon, nitrogen and phosphorus removal efficiencies were reached in different HRAPs treating urban wastewaters located in two different temperate (Mediterranean and oceanic) climates. Furthermore, similar ecological successions were observed in these HRAPs. During the start-up phase, the consumption of organic matter by detritivores, already present in the wastewater, appears to be necessary for the microalgae to grow within two weeks in spring. The growth of the rapid-growing species, Chlorella sp., followed by the grazing-resilient species, Scenedesmus sp., combined with nitrifying and denitrifying bacterial activity, removed most the ammonia. The resulting exhaustion of ammonia would limit the complete removal of dissolved COD by bacteria and phosphate by microalgae in the HRAPs. This study shows that similar biological and environmental constraints were applied on the HRAPs, making the process efficiency highly reproducible under different temperate latitudes

IFN-α improves PhAg-induced IFN-γ production by Vγ9Vδ2 T-cells in HD and in non-human primates.

<p>(<b>A</b>) A quantitative analysis of IFN-γ production was performed <i>in vitro</i> by stimulating purified Vγ9Vδ2 T-cells from 6 HD by ELISA after medium (white boxes), IFN-α (grey boxes), PhAg (hatched boxes) and PhAg/IFN-α (dark grey boxes) stimulation. Statistical analysis was performed by Mann-Whitney test, **p<0.01 ***p<0.0001. (<b>B</b>) Plasma IFN-γ levels from <i>in vivo</i> PhAg (white dots, n = 4) and PhAg/IFN-α (black dots, n = 4) treated monkeys was quantified by ELISA test.</p

IFN-α improves <i>in vitro</i> PhAg-induced IFN-γ production of Vγ9Vδ2 T-cells in HCV patients.

<p>(<b>A,B</b>) A quantitative analysis of IFN-γ production was performed in HD (n = 35, Panel A) and in HCV (n = 24, Panel B) by ELISA after medium (white boxes), IFN-α (grey boxes), PhAg (hatched boxes) and PhAg/IFN-α (dark grey boxes) stimulation. Statistical analysis was performed by Mann-Whitney test, **p<0.01 ***p<0.0001. (<b>C</b>) The percentage of increase in IFN-γ production after combined PhAg/IFN-α respect to single PhAg stimulation was compared between HD (white bar) and HCV patients (grey bar). Statistical analysis was performed by Mann-Whitney test, **p<0.01.</p

Chronic HCV infection induces an increase in activated/effectors Vγ9Vδ2 T-cells. (A)

<p>Representative flow cytometry panels on Vγ9Vδ2 T-cells frequency and differentiation profile are shown for one healthy donor and one HCV-infected patient. Differentiation was analyzed by monitoring CD27 and CD45RA expression. Naïve: CD45RA+CD27+; Central Memory: CD45RA-CD27+; Effector Memory: CD45RA-CD27-; Effectors: CD45RA+CD27-. (<b>B</b>) Statistical analysis of Vγ9Vδ2 T-cell differentiation profile from HD (white boxes, n = 35) and HCV (grey boxes n = 24) was performed by Mann-Whitney test. *p<0.05. (<b>C</b>) Representative flow cytometry panels on CD25 and CD69 expression on Vγ9Vδ2 T-cells are shown for one healthy donor and one HCV-infected patient. (<b>D</b>) Statistical analysis of CD25 and CD69 expression on Vγ9Vδ2 T-cells from HD (white boxes, n = 35) and HCV (grey boxes n = 24) was performed by Mann-Whitney test. *p<0.05.</p

Chronic HCV infection induces a strong impairment in IFN-γ production. (A)

<p>A quantitative analysis of IFN-γ produced by unstimulated and PhAg-stimulated Vγ9Vδ2 T-cells from HD (n = 20, white boxes) and HCV (n = 24, grey boxes) was performed by ELISA assay. (<b>B</b>) The frequency of IFN-γ-producing Vγ9Vδ2 T-cells after PhAg stimulation was analyzed by intracellular staining and flow cytometry. Statistical analysis was performed by Mann-Whitney test, *p<0.05; ***p<0.0001. (<b>C</b>) Representative flow cytometry histograms of IFN-γ MFI (Median Fluorescence Intensity) produced by Vγ9Vδ2 T-cells after PhAg stimulation are shown for one healthy donor and one HCV-infected patient.</p

Main clinical features of Healthy Donors (HDs) and HCV patients.

<p>n.t.: not tested.</p