Similarly, when myeloid DCs were stimulated with CD40L in the presence of HCV core, p9 enhanced IL-12 production by inhibiting HCV core-induced as well as CD40L-induced IL-10. Moreover, in vitro, p13 potentiated the effect of maturation stimuli on human and murine DC, increasing their IL-12 production and stimulatory activity, which resulted in enhanced proliferation and IFN-γ production

by responding T-cells. Finally, immunization with p13-treated murine DC induced stronger anti-HCV T-cell responses not only in wildtype mice but also in HCV transgenic mice and in mice transiently expressing HCV core in the liver. Conclusion: These results suggest that IL-10 inhibiting peptides may have important applications to enhance anti-HCV XL765 concentration immune responses by restoring the immunostimulatory capabilities of DC. (HEPATOLOGY 2011.) Chronic infection caused by hepatitis C virus (HCV) is characterized by low or nil antiviral T-cell responses, whereas viral clearance is associated with strong and multispecific T-cell responses.1 Among other mechanisms, production of immunosuppressive

cytokines such as interleukin 10 (IL-10)2, 3 has been postulated as responsible for this lack of efficient immunity. IL-10 is a pleiotropic cytokine traditionally considered as immunosuppressive and antiinflammatory, produced by many cell types (reviewed4), which exerts its effects by inhibiting www.selleckchem.com/products/Sunitinib-Malate-(Sutent).html macrophage and dendritic cell this website (DC) functions. In chronic HCV infection, patients have high serum levels of IL-10,5, 6 associated with incomplete responses to interferon IFN therapy.7 Interestingly,

these levels decline after successful treatment.6 IL-10 is produced in these patients by antigen-stimulated CD4 and CD8 T-cells, regulatory T-cells,3, 8, 9 and DC10-12 which in turn activate IL-10-producing T-cells.13In vitro experiments have demonstrated that some HCV proteins interacting with monocytes induce the production of IL-10.14, 15 Due to its antiinflammatory properties, IL-10 has been used therapeutically in HCV patients with liver fibrosis.16 Although administration of IL-10 decreased hepatic inflammation and fibrosis, HCV RNA levels increased, and antiviral CD4 and CD8 T-cells shifted from a Th1 to a Th2 cytokine profile. All these data suggest that overexpression of IL-10 in chronic HCV infection may contribute to the lack of efficient antiviral T-cell responses. Indeed, IL-10 is a key factor in determining viral clearance versus chronic infection in the LCMV murine model, and its inhibition converted a chronic into an acute infection, which could be controlled by the immune response.17, 18 Thus, for chronic HCV infection, inhibition of IL-10 would potentially enhance the efficacy of antiviral responses and, ultimately, lead to viral clearance.