To determine whether DNA based immunization could protect newborn chim
panzees against a challenge infection with hepatitis B virus, two chim
panzees were immunized on the day of birth with a plasmid coding for h
epatitis B surface antigen, and boosted at 6 and 24 weeks. Both animal
s produced transient antibody to the hepatitis B surface antigen. Foll
owing challenge with hepatitis B virus at 33 weeks the two immunized a
nimals developed anamnestic antibody responses, however, neither devel
oped detectable hepatitis B surface antigen or antibody to the core pr
otein, the conventional markers of hepatitis B infection. Both of thes
e markers appeared in an unimmunized control animal. We conclude that
DNA based immunization can induce protective immunity in newborn chimp
anzees. (C) 1997 Elsevier Science Ltd.