Phenotype and function of monocyte-derived dendritic cells in neonates born to Hepatitis B virus-positive mothers

Hepatitis B Virus (HBV) infection in infancy or early childhood leads to high rate of persistent infection (25-90%). The immunological basis of high rate of viral persistence in vertically acquired HBV infections is not completely understood. Dendritic cells (DCs) are one of the most potent antigen-presenting cells (APC) and play pivotal roles in the enhancement or regulation of antiviral immune reactions. Aim of the present study was to investigate whether an HBV-infected maternal environment might influence the infants’ DC phenotype and function. Monocyte-derived DC (MoDC) of neonates born to HBsAg-positive mothers were studied phenotypically by Flow Cytometry (FCM) and functionally by mixed lymphocyte reaction (MLR) and enzyme-linked immunosorbent assay (ELISA). An electron microscope was used to analyze the morphological changes of MoDC. MoDC from neonates whose maternal HBV DNA was>5×107 copies/ml showed a reduced surface expression of CD80, CD86, and HLA-DR as compared to that in neonates whose maternal HBV DNA was negative (CD80: t=3.238, P=0.002; CD86: t=3.543, P=0.001; HLA-DR: t=2.785, P=0.008). T-cell proliferation assays also showed an impaired allostimulatory capacity in comparison to that in neonates whose maternal HBV DNA was negative, especially in the cultures at a DC: T cell ratios of 1:5 and 1:10 (t=-5.442, P