Vaccination against hepatitis delta virus infection: Studies in the woodchuck (Marmota monax) model

Hepatitis delta virus (HDV) superinfection of hepatitis B virus carriers ca uses severe liver disease and results in a high rate of chronicity. So far, neither sufficient therapy nor vaccines to prevent HBV carriers from super infection are available. A good model to test vaccine candidates is the woo dchuck chronically infected with the woodchuck hepatitis virus (WHV); the w oodchuck can be superinfected with HDV and shows a course of infection simi lar to that of patients. Different strategies have been investigated to est ablish a protective vaccine against HDV superinfection. Both proteins of HD V (HDAg p24 and p27), which differ only in the C-terminal amino acid sequen ce, have been used as vaccine candidates. Synthetic peptides derived from B cell epitopes of HDAg and HDAg p24 expressed in Escherichia coli, yeast, o r baculovirus have been used to immunize woodchucks. The protein immunizati on induced a specific antibody response, however, no protection from HDV su perinfection was achieved. Vaccinations with vaccinia virus expressing HDAg p24 or p27 and DNA immunization with vectors expressing p24 were also not able to induce a protective immune response, but seemed to modulate the cou rse of HDV superinfection. Thus, new strategies to develop a vaccine to pre vent HDV superinfection are needed. Copyright (C) 2001 S. Karger AG, Basel.