Elimination of immune tolerance to hepatitis virus in an animal model

Four-day old ducklings were infected with duck hepatitis B virus to simulate perinatal transmission of hepatitis B virus. Immune tolerance was characterized as persistent viremia, antigenemia, without detection of anti-DHBs or anti-DHBc. A synthetic peptide, P125-146, mimicking one of the epitopes of the native DHBV Pre-S protein was used to cross-link to tetanus toxoid or phytohemagglutinin. These 'novel' antigens were used to immunize immune tolerant ducks, aimed at bypassing T cell tolerance. After 5 injections, though no anti-DHBV Pre-S was detected, around 50% of the immunized ducks showed seroconversion to DHBV DNA negative.