New hepatitis B virus immunology research from Erasmus University discussed
February 23rd, 2009
2009 FEB 23 -- Research findings, 'Hepatitis B virus surface antigen impairs myeloid dendritic cell function: a possible immune escape mechanism of hepatitis B virus,' are discussed in a new report. According to recent research published in the journal Immunology, "Chronic hepatitis B virus (HBV) infection is the result of an inadequate immune response towards the virus. Myeloid dendritic cells (mDC) of patients with chronic HBV are impaired in their maturation and function, resulting in more tolerogenic rather than immunogenic responses, which may contribute to viral persistence."
"The mechanism responsible for altered mDC function remains unclear. The HBV-infected patients display large amounts of HBV particles and viral proteins in their circulation, especially the surface antigen HBsAg, which allows multiple interactions between the virus, its viral proteins and DC. To assess whether HBV directly influences mDC function, the effects of HBV and HBsAg on human mDC maturation and function were investigated in vitro. As already described for internalization of HBV by DC, the present study shows that peripheral blood-derived mDC of healthy controls also actively take up HBsAg in a time-dependent manner. Cytokine-induced maturation in the presence of HBV or HBsAg resulted in a significantly more tolerogenic mDC phenotype as demonstrated by a diminished up-regulation of costimulatory molecules and a decreased T-cell stimulatory capacity, as assessed by T-cell proliferation and interferon-gamma production. In addition, the presence of HBV significantly reduced interleukin-12 production by mDC. These results show that both HBV particles and purified HBsAg have an immune modulatory capacity and may directly contribute to the dysfunction of mDC in patients with chronic HBV," wrote den Brouw M.L. Op and colleagues, Erasmus University.
The researchers concluded: "The direct immune regulatory effect of HBV and circulating HBsAg particles on the function of DC can be considered as part of the mechanism by which HBV escapes immunity."
Op and colleagues published their study in Immunology (Hepatitis B virus surface antigen impairs myeloid dendritic cell function: a possible immune escape mechanism of hepatitis B virus. Immunology, 2009;126(2):280-9).
For additional information, contact M.L. Op den Brouw, Erasmus MC, Dept. of Gastroenterology and Hepatology, Rotterdam, Netherlands.
The publisher's contact information for the journal Immunology is: Blackwell Publishing Inc., 350 Main St., Malden, MA 02148, USA.
Keywords: Netherlands, Rotterdam, Hepatitis B Virus Immunology, Antigens, Gastroenterology, HBV, Hepatitis B Virus, Hepatology, Immunology, Infectious Disease, Viral, Virology.
This article was prepared by Hepatitis Weekly editors from staff and other reports. Copyright 2009, Hepatitis Weekly via NewsRx.com.
