Early life humoral response of ducks to DNA immunization against hepadnavirus large envelope protein

DNA vaccination may represent an interesting strategy for early life immuni zation. However, in some cases, this approach has been shown to induce a to lerance rather than immunity. We have compared the efficiency of neonatal D NA or protein immunization against hepadnavirus envelope protein using the duck hepatitis B virus (DHBV) model. Three-day-old ducklings were immunized with either a plasmid encoding the DHBV pre-S/S large envelope protein (L) , or a recombinant preS protein, followed by sequential DNA or protein boos ts at weeks 4 and 15. Our results showed that genetic immunization of duck neonates induced specific humoral response to DHBV L protein. Interestingly , an enhanced antibody response was elicited when animals received DNA prim ing-DNA boosting as compared to DNA priming-protein boosting. (C) 2000 Else vier Science Ltd. All rights reserved.