Active immunization against transforming growth factor beta1 prevents hepatic fibrosis in a rat model of liver disease

Abstract

Transforming growth factor beta1 (TGF-β1) plays an important role in hepatic fibrogenesis. In this study, we documented the effects of active immunization against TGF-β1 on hepatic fibrosis in an animal model of chronic liver disease. BALB/c mice were immunized against 3 different peptides of TGF-β1 ligated into hepatitis B virus core protein (HBVc). Titers of TGF-β1 antibodies were documented by enzyme linked immunoassays and antibody activity by cell membrane receptor binding and proliferation assays. The most immunogenic recombinant HBVc + TGF-β1 peptide (HBVc + C) then served as a vaccine in Sprague-Dawley rats with dimethylnitrosamine-induced chronic liver disease. Hepatic fibrosis was documented by serum hyaluronic acid levels, liver histology, and reverse transcriptase polymerase chain reaction for hepatic collagen I (α1) and smooth muscle alpha actin mRNA expression. Relative to control rats vaccinated with HBVc alone, recombinant HBVc + C vaccinated animals had significantly lower serum hyaluronic acid levels, less histologic evidence of hepatic fibrosis, and reduced expression of collagen I (α1) and smooth muscle alpha actin mRNA in the liver. The results of this proof-of-concept study suggest that active immunization against TGF-β1 is a worthwhile strategy to pursue in efforts to prevent hepatic fibrosis associated with chronic liver disease.