Expression of hepatitis B virus surface antigen gene in insect baculovirus vector systems.

The gene coding for the hepatitis B virus surface antigen (HBsAg) under the control of Autographa californicanuclear polyhedrosis virus polyhedrin promoter was successfully inserted into the genome of the Trichoplusia ni nuclear polyhdrosis virus. Infection of Spodoptera frugiperda cells with this recombinant virus produced a significant amount of HBsAg protein and secreted 22 nm particles containing the HBsAg. The expression of HBsAg gene was also obtained both in Trichoplusia ni larvae and in Philosamia cynthia ricini prepupae when infected with the recombinant virus. The HBsAg proteins expressed by baculovirus vector systems have morphological and antigenic properties identical to the 22 nm particles secreted by human cells.