| Abstract: | BACKGROUND/AIMS: The magnitude of antigen-specific immunity was assessed in a murine model of nonalcoholic fatty liver diseases (NAFLD). Because antigen-specific immunity was diminished in NAFLD mice, the underlying mechanisms were evaluated through analysis of the functions of antigen-presenting dendritic cells (DC) and other immunocytes. METHODS: For 12 weeks, NAFLD mice received a high-fat (60%) and high-calorie (520 kcal/100 g) diet. C57BL/6 mice (controls) received a standard diet. NAFLD mice and control mice were immunized with hepatitis B vaccine containing hepatitis B surface antigen (HBsAg) and hepatitis B core antigen (HBcAg). Antibody to HBsAg (anti-HBs), HBsAg and HBcAg-specific cellular immune response and functions of whole spleen cells, T lymphocytes, B lymphocytes and spleen DCs of NAFLD and control mice were assessed in vitro. RESULTS: Levels of anti-HBs and the magnitude of proliferation of HBsAg and HBcAg-specific lymphocytes were significantly lower in NAFLD mice than control mice (P < 0.05). The spleen cells of NAFLD mice produced significantly higher levels of inflammatory cytokines (P < 0.05) and exhibited significantly increased T cell proliferation compared with control mice (P < 0.05). However, the antigen processing and presenting capacities of spleen DCs were significantly decreased in NAFLD mice compared with control mice (P < 0.05). Palmitic acid, a saturated fatty acid, caused diminished antigen processing and presenting capacity of both murine and human DCs. CONCLUSIONS: Nonalcoholic fatty liver disease mice exhibit decreased magnitudes of antigen-specific humoral and cellular immune responses. This effect is mainly, if not solely, due to impaired antigen processing and presentation capacities of DC. |
