Abstract
Inactivated subunit vaccine of Newcatle disease virus (NDV) was prepared from NDV fusion protein in Bombyx mori pupae by gene transfer using a hybrid baculovirus vector, and its potency was evaluated. The subunit vaccine was very effective against challenge by virulent NDV. Neutralization antibody was produced in vaccinated chickens with the extremelydiluted vaccine, whereas hemagglutinatinginhibition (HI) antibody was not detected in vaccinated chickens even with the mildlydiluted or nondiluted vaccines. HI titers were elevated markedly in resisted chickens against the challenge. The potency of the vaccine was very high and stable after refrigeration storage for 9 months. The antigen prodduced in Bombyx mori pupae by the hybrid baculovirus recombinant was also stable, even if serial passage was done five times in Spodoptera frugiperda cells.
