Regulatory T Cells in Autoimmune and Viral Chronic Hepatitis

Figure 2

Role of CD4⁺ Tregs in chronic viral hepatitis. Based on data from chronically HCV-infected patients and experimental models, we propose the following role for CD4⁺ Tregs in chronic viral hepatitis. When liver cells are exposed to viral particles within the context of minimal innate immune responses and inflammatory signals, antigen presentation of virus-derived peptides by hepatocytes could occur with minimal costimulation and within the tolerogenic environment of the hepatic sinusoid (IL-10 and TGF-β) leading to the conversion of virus-specific naïve CD4⁺ T cells into Tregs (left). Antigen presentation by liver sinusoidal endothelial cells (LSEC) could also occur through the release of viral antigens by hepatocyte turnover leading to the conversion of virus-specific naïve CD4⁺ T cells into CD4⁺ Tregs. These virus-specific CD4⁺ Tregs could then inhibit the activation of virus-specific effector T cells and efficient antigen presentation by APCs through IL-10 secretion.