Hepatitis C virus NS4 uses subversive tactics to thwart Th1 response.

2004 FEB 11 - (NewsRx.com & NewsRx.net) -- Hepatitis C virus NS4 uses subversive tactics to thwart Th1 response.

According to recent research published in the European Journal of Immunology, "the majority of hepatitis C virus (HCV) infections become chronic, despite the presence of HCV-specific cellular and humoral immune responses. We have previously suggested that interleukin (IL)-10-secreting antigen-specific regulatory T cells may contribute to viral persistence, and demonstrate here that peripheral blood mononuclear cells (PBMC) from chronically HCV-infected patients secrete IL-10, but not IFN-gamma, in response to HCV nonstructural protein 4 (NS4). A neutralizing anti-IL-10 antibody restored this defective antigen-specific interferon (IFN)-gamma production in vitro."

"Furthermore, PBMC from normal individuals secreted IL-10 in response to NS4, suggesting that cells of the innate immune system, in addition to T cells, produced IL-10 in the HCV-infected patients," wrote M.T. Brady and colleagues, Trinity College, Dublin, Immune Regulation Research Group.

"Cell separation experiments revealed that the innate IL-10 was produced by blood monocytes, but not dendritic cells (DC). In addition, NS4 inhibited IL-12 production by PBMC in response to lipopolysaccharide (LPS) and IFN-gamma, and Th1 responses to recall ...